Solo 2350D won't start

[BillT]

Our Duo's turbo has suddenly stopped working. It spins up ok at 55Kt when decompressed & continues windmilling when the decompression is released. The engine starts after 2 - 3 seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it starts again & the sequence is repeated. It's as if the rpm cut out is operating (which happens if the revs exceed 6500) but I'm certain that's not happening & have been careful to ensure the speed doesn't exceed 60Kt. Any advice will be appreciated. Thanks, Bill

[[email protected]]

On Friday, March 20, 2020 at 6:42:42 PM UTC-4, BillT wrote:
> Our Duo's turbo has suddenly stopped working. It spins up ok at 55Kt when decompressed & continues windmilling when the decompression is released. The engine starts after 2 - 3 seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it starts again & the sequence is repeated. It's as if the rpm cut out is operating (which happens if the revs exceed 6500) but I'm certain that's not happening & have been careful to ensure the speed doesn't exceed 60Kt. Any advice will be appreciated. Thanks, Bill

Check for blocked or collapsed fuel lines.
UH

[Bruce Friesen]

On Friday, March 20, 2020 at 3:42:42 PM UTC-7, BillT wrote:
> Our Duo's turbo has suddenly stopped working. It spins up ok at 55Kt when decompressed & continues windmilling when the decompression is released. The engine starts after 2 - 3 seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it starts again & the sequence is repeated. It's as if the rpm cut out is operating (which happens if the revs exceed 6500) but I'm certain that's not happening & have been careful to ensure the speed doesn't exceed 60Kt. Any advice will be appreciated. Thanks, Bill

Check fuel pump for outlet pressure (not just confirming flow, actually measuring the pressure and compare to spec sheet).

[Nick Kennedy[_3_]]

Does sound like a intermittent fuel delivery problem.
How do you start a turbo on the ground?
Thought they were only windwill starts?
Don't know never have had one.

[Bob Gibbons[_2_]]

On Fri, 20 Mar 2020 15:42:39 -0700 (PDT), BillT
> wrote:

>Our Duo's turbo has suddenly stopped working. It spins up ok at 55Kt when decompressed
>& continues windmilling when the decompression is released. The engine starts after 2 - 3
>seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it starts again & the sequence >
>is repeated. It's as if the rpm cut out is operating (which happens if the revs exceed 6500)
>but I'm certain that's not happening & have been careful to ensure the speed doesn't exceed
>60Kt. Any advice will be appreciated. Thanks, Bill

About 10 years ago I had a similar issue with my Ventus cT (same
engine, but direct drive). Problem turned out to be the impulse fuel
pump diaphragm that had gotten stiff with age. A simple job to replace
(provided you can get the parts). 10 years ago parts were not an
issue, now, I am unsure. I so have photos of the replacement procedure
if interested.

Bob

[AS]

On Friday, March 20, 2020 at 6:42:42 PM UTC-4, BillT wrote:
> Our Duo's turbo has suddenly stopped working. It spins up ok at 55Kt when decompressed & continues windmilling when the decompression is released. The engine starts after 2 - 3 seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it starts again & the sequence is repeated. It's as if the rpm cut out is operating (which happens if the revs exceed 6500) but I'm certain that's not happening & have been careful to ensure the speed doesn't exceed 60Kt. Any advice will be appreciated. Thanks, Bill

Is the fuel tank vented properly?

Uli
'AS'

[Jonathon May]

At 01:50 21 March 2020, Bob Gibbons wrote:
>On Fri, 20 Mar 2020 15:42:39 -0700 (PDT), BillT
> wrote:
>
>>Our Duo's turbo has suddenly stopped working. It spins up ok at
55Kt when
>decompressed
>>& continues windmilling when the decompression is released. The
engine
>starts after 2 - 3
>>seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it
starts
>again & the sequence >
>>is repeated. It's as if the rpm cut out is operating (which happens
if the
>revs exceed 6500)
>>but I'm certain that's not happening & have been careful to
ensure the
>speed doesn't exceed
>>60Kt. Any advice will be appreciated. Thanks, Bill
>
>About 10 years ago I had a similar issue with my Ventus cT (same
>engine, but direct drive). Problem turned out to be the impulse fuel
>pump diaphragm that had gotten stiff with age. A simple job to
replace
>(provided you can get the parts). 10 years ago parts were not an
>issue, now, I am unsure. I so have photos of the replacement
procedure
>if interested.






>
>Bob
>


I think the 5 year check has a replacement for the diaphragm ,so
they are an obvious known fault.

[Nick Kennedy[_3_]]

How do you start a Turbo engine on the ground to work on it?
Can you?
Can you Hand Prop it?
It would be nice if they had a fitting to attach a 1/2" drill motor to turn it over.
I, obviously, know very little about these engines, just curious.

[john firth]

On Friday, March 20, 2020 at 6:42:42 PM UTC-4, BillT wrote:
> Our Duo's turbo has suddenly stopped working. It spins up ok at 55Kt when decompressed & continues windmilling when the decompression is released. The engine starts after 2 - 3 seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it starts again & the sequence is repeated. It's as if the rpm cut out is operating (which happens if the revs exceed 6500) but I'm certain that's not happening & have been careful to ensure the speed doesn't exceed 60Kt. Any advice will be appreciated. Thanks, Bill

I have made new diaphragms for a Mikuni pump from 5 mil mylar (artists supplies)
Use the cast plate as a template and melt the screw holes with a soldering iron.
JMF

[[email protected]]

John does the mylar resist the effects of the fuel or do you find you have replace that diafram frequently?
Dan

[john firth]

On Friday, March 20, 2020 at 6:42:42 PM UTC-4, BillT wrote:
> Our Duo's turbo has suddenly stopped working. It spins up ok at 55Kt when decompressed & continues windmilling when the decompression is released. The engine starts after 2 - 3 seconds, runs for 2 seconds then cuts out. After 1 - 2 seconds it starts again & the sequence is repeated. It's as if the rpm cut out is operating (which happens if the revs exceed 6500) but I'm certain that's not happening & have been careful to ensure the speed doesn't exceed 60Kt. Any advice will be appreciated. Thanks, Bill

first ones lasted 6-7 years but stretched enough that the fuel pressure
dropped.
JMF

[[email protected]]

I believe the SH gliders ship with a yellow strap that is wrapped around the propeller hub. Lak used a cord, but the process is basically the same.

Only to be attempted with the utmost care and always with the wings attached....

https://youtu.be/C0UJtqhZJMo

[BillT]

On Sunday, March 22, 2020 at 6:51:13 AM UTC+11, wrote:
> I believe the SH gliders ship with a yellow strap that is wrapped around the propeller hub. Lak used a cord, but the process is basically the same.
>
> Only to be attempted with the utmost care and always with the wings attached....
>
> https://youtu.be/C0UJtqhZJMo

Thanks to all who responded. For those not familiar with the Solo 2350D, the following should help. The engine is windmill started in flight. There is an adaptor on the prop hub to enable an electric drill to be used to start the engine – I assume this is for factory testing. Thanks for the video showing the strap method, but I’ve been advised not to try this. The Duo has two fuel pumps – a pilot activated electric Facet, located under the rear seat & a vacumn diaphragm on the pilon under the engine. There is no throttle – when it starts it runs at full power. Fuel used is premium unleaded (98) which has no ethanol. The engine has a cutout function which occurs if the revs exceed 6500rpm – it cuts back in once the revs drop below 6500. Keeping the airspeed at 50 – 55Kts prevents over revving.
What I’ve done so far. Checked the Facet for fuel flow & it’s ok. Pumped 10 L of fuel from the tank in 12 minutes, so tank venting is ok. When starting the engine the electric pump is used until the engine starts & then the diaphragm pump takes over. I haven’t checked the diaphragm pump but will try the syringe method. SH advise this pump is no longer manufactured & an overhaul kit is not available. These pumps were also used on outboard motors & there are aftermarket overhaul kits available eg.. https://www.westmarine.com/buy/sierra--fuel-pump-johnson-evinrude-replaces-438616--1764349 https://www.westmarine.com/buy/sierra--fuel-pump-repair-kit-for-omc-393103--210893
If any one has used one of these, please me know. SH are now supplying an alternate pump which I believe is a Mikuni. Also can anyone advise what the pump pressure should be?
I’ve also stripped & cleaned both carby’s – no sign of any problems, but I intend to order new gaskets & diaphragms. This problem arose soon after the annual inspection, during which both NGK spark plugs were replaced. I’ll fit two new plugs in case one is faulty. And I’ll pull the seat pan to ensure there are no kinks in the fuel line. Regards, Bill

[Charlie M. (UH & 002 owner/pilot)]

As a long term poster on car forums.....fantastic feedback....thanks (for someone that may ask, no known neurological issues other than flying without an engine....;-))...extra dots may be likened to a pause when actually speaking to someone...

I was thinking either a collapsing fuel line, tank cap that wasn't venting, possibly a bad diaphragm (wasn't sure if float or diaphragm).

Spark plugs....not a typical issue....very low on trouble shooting list. Sounds like fuel, but short duration.

Whenever you find the issue, PLEASE post back on resolution, too many forums someone posts an issue, many possible fixes, usually never feedback on resolution.
Help the next peep that actually searches.....

Thanks.

[2G]

On Saturday, March 21, 2020 at 4:32:59 PM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
> As a long term poster on car forums.....fantastic feedback....thanks (for someone that may ask, no known neurological issues other than flying without an engine....;-))...extra dots may be likened to a pause when actually speaking to someone...
>
> I was thinking either a collapsing fuel line, tank cap that wasn't venting, possibly a bad diaphragm (wasn't sure if float or diaphragm).
>
> Spark plugs....not a typical issue....very low on trouble shooting list. Sounds like fuel, but short duration.
>
> Whenever you find the issue, PLEASE post back on resolution, too many forums someone posts an issue, many possible fixes, usually never feedback on resolution.
> Help the next peep that actually searches.....
>
> Thanks.

One thing often overlooked with diaphragm carbs is the pop-off pressure of the needle valve. Incorrect pop-off pressure might account for this behavior. This pressure can usually be adjusted by either changing the spring or by bending the needle lever.

https://www.google.com/search?sxsrf=ALeKk007fCHWuhEPxpQiyvhLPQZ-WMZCmQ%3A1584835532804&source=hp&ei=zKt2XonHLtj4-wSDgrmoCA&q=carb+pop+off+tester&oq=carb+pop&gs_l=psy-ab.3.2.0l8j0i22i30l2.2146.4148..8689...2.0..0.132. 905.1j7......0....1..gws-wiz.....10..35i362i39j35i39j0i273j0i131j0i67j0i20i 263j0i131i67j0i10.f9GczK9WkxE

Tom

[BillT]

On Sunday, March 22, 2020 at 11:08:36 AM UTC+11, 2G wrote:
> On Saturday, March 21, 2020 at 4:32:59 PM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
> > As a long term poster on car forums.....fantastic feedback....thanks (for someone that may ask, no known neurological issues other than flying without an engine....;-))...extra dots may be likened to a pause when actually speaking to someone...
> >
> > I was thinking either a collapsing fuel line, tank cap that wasn't venting, possibly a bad diaphragm (wasn't sure if float or diaphragm).
> >
> > Spark plugs....not a typical issue....very low on trouble shooting list.. Sounds like fuel, but short duration.
> >
> > Whenever you find the issue, PLEASE post back on resolution, too many forums someone posts an issue, many possible fixes, usually never feedback on resolution.
> > Help the next peep that actually searches.....
> >
> > Thanks.
>
> One thing often overlooked with diaphragm carbs is the pop-off pressure of the needle valve. Incorrect pop-off pressure might account for this behavior. This pressure can usually be adjusted by either changing the spring or by bending the needle lever.
>
> https://www.google.com/search?sxsrf=ALeKk007fCHWuhEPxpQiyvhLPQZ-WMZCmQ%3A1584835532804&source=hp&ei=zKt2XonHLtj4-wSDgrmoCA&q=carb+pop+off+tester&oq=carb+pop&gs_l=psy-ab.3.2.0l8j0i22i30l2.2146.4148..8689...2.0..0..132 .905.1j7......0....1..gws-wiz.....10..35i362i39j35i39j0i273j0i131j0i67j0i20i 263j0i131i67j0i10.f9GczK9WkxE
>
> Tom

I'd never heard of the "pop off" pressure test. The 5 year inspection schedule for the original 2350 requires a pressure test of 0.4 bar (~ 6psi) allowed to decrease by 0.1 bar/min. https://aircraft.solo.global/img/cms/pdfs/Sonderkontrolle-2350_012015_Englisch.pdf
Both of the carbys on our 2350D met this requirement indicating the needle & seat are ok. I'll report the outcome of fault finding, but it could be a few weeks. Rgds, Bill

[Mike N.]

I am having a similar problem in my Ventus Ct. Mine will not start at all.

Is there any way to check for spark on the ground?
I pulled the plugs and hand propped while holding the plugs to the side of the engine case and could see no spark.

Is there a A&P familiar with the Solo motors in south east U.S., or better yet Florida?

Thanks for any help.
Mike

[Dan Marotta]

Can you do that manual spark test in a hangar?Â* In dim(mer) light you
should be able to see a spark, if there.Â* Or you could have your plugs
tested, or simply replace them.

On 3/24/2020 4:55 AM, Mike N. wrote:
> I am having a similar problem in my Ventus Ct. Mine will not start at all.
>
> Is there any way to check for spark on the ground?
> I pulled the plugs and hand propped while holding the plugs to the side of the engine case and could see no spark.
>
> Is there a A&P familiar with the Solo motors in south east U.S., or better yet Florida?
>
> Thanks for any help.
> Mike

--
Dan, 5J

[Dave Nadler]

On Tuesday, March 24, 2020 at 6:55:06 AM UTC-4, Mike N. wrote:
> I am having a similar problem in my Ventus Ct. Mine will not start at all.
>
> Is there any way to check for spark on the ground?
> I pulled the plugs and hand propped while holding the plugs to the side of the engine case and could see no spark.
>
> Is there a A&P familiar with the Solo motors in south east U.S., or better yet Florida?
>
> Thanks for any help.
> Mike

Not expert on this contraption, however:
- coil failures are not uncommon (vibration breaks of lead at coil), and
- IIRC mechanic at Seminole is familiar with Solo sustainers
Hope that helps,
Best Regards, Dave

PS: Sounds like you already did the coil test and saw no spark, right?

[Nick Kennedy[_3_]]

Nadler could be on to something here, intermittent coil failure. Especially if this is a know past fault point.
If you did a fuel flow test and rebuilt the carbs, It points to a intermittent electrical problem.
You need spark, fuel and compression.
What makes you certain the over rev cut out is not kicking in?
Can you disconnect it for testing purposes?
If the problem is intermittent I think the Plugs might be OK.
If not dropped plugs are pretty tough, simple and trouble free
but you never know.

[Ventus_a]

I am having a similar problem in my Ventus Ct. Mine will not start at all.

Is there any way to check for spark on the ground?
I pulled the plugs and hand propped while holding the plugs to the side of the engine case and could see no spark.

Is there a A&P familiar with the Solo motors in south east U.S., or better yet Florida?

Thanks for any help.
Mike

Hi Mike

Even if you were getting a spark it might not be that helpful in diagnosing the reason for not starting.

An acquaintance with a D2cT was having a similar problem. He was getting spark, testing as you did. He also had the coils bench tested as being ok but it eventually turned out they were breaking down under load so no joy. He is an experienced 2T & 4T mechanic who used to road race back in the day and he was stumped by it

New coils fixed his problem

:-/ Colin

[Dan Marotta]

Excellent point!

I recall my Harley cutting out on a road trip.Â* I reached down and
touched the coil and got a shock.Â* I replaced the coil and have had
another 100K trouble free miles (with more to go).

On 3/24/2020 10:00 AM, Dave Nadler wrote:
> On Tuesday, March 24, 2020 at 6:55:06 AM UTC-4, Mike N. wrote:
>> I am having a similar problem in my Ventus Ct. Mine will not start at all.
>>
>> Is there any way to check for spark on the ground?
>> I pulled the plugs and hand propped while holding the plugs to the side of the engine case and could see no spark.
>>
>> Is there a A&P familiar with the Solo motors in south east U.S., or better yet Florida?
>>
>> Thanks for any help.
>> Mike
> Not expert on this contraption, however:
> - coil failures are not uncommon (vibration breaks of lead at coil), and
> - IIRC mechanic at Seminole is familiar with Solo sustainers
> Hope that helps,
> Best Regards, Dave
>
> PS: Sounds like you already did the coil test and saw no spark, right?

--
Dan, 5J

[Mike N.]

I'll call Seminole tomorrow and see if they can troubleshoot.

I am also thinking about getting the pump rebuild lots mentioned earlier in the thread.

Thanks

[BillT]

On Wednesday, March 25, 2020 at 12:31:27 PM UTC+11, Mike N. wrote:
> I'll call Seminole tomorrow and see if they can troubleshoot.
>
> I am also thinking about getting the pump rebuild lots mentioned earlier in the thread.
>
> Thanks

I spent a couple of hours Saturday checking suggestions from this group & others. Electrical - a friend put a megga on the spark plugs & tells they're ok. Checked ignition module secondary for continuity - both ok, checked the terminal block on the engine bay firewall for loose connections - all good.
Fuel - removed the pulse line from the diaphragm pump & connected a syringe - it pumped ok. Checked carby inlets & exhaust for blockage (mud wasp nests) - all clear. I've ordered Carby diaphragms, gaskets & metering modules from SH so it may be a few weeks before these are installed. Next problem will be getting a launch to test fly - probably no operations due Cov 19. Rgds, Bill

[2G]

On Sunday, March 22, 2020 at 3:39:05 PM UTC-7, BillT wrote:
> On Sunday, March 22, 2020 at 11:08:36 AM UTC+11, 2G wrote:
> > On Saturday, March 21, 2020 at 4:32:59 PM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
> > > As a long term poster on car forums.....fantastic feedback....thanks (for someone that may ask, no known neurological issues other than flying without an engine....;-))...extra dots may be likened to a pause when actually speaking to someone...
> > >
> > > I was thinking either a collapsing fuel line, tank cap that wasn't venting, possibly a bad diaphragm (wasn't sure if float or diaphragm).
> > >
> > > Spark plugs....not a typical issue....very low on trouble shooting list. Sounds like fuel, but short duration.
> > >
> > > Whenever you find the issue, PLEASE post back on resolution, too many forums someone posts an issue, many possible fixes, usually never feedback on resolution.
> > > Help the next peep that actually searches.....
> > >
> > > Thanks.
> >
> > One thing often overlooked with diaphragm carbs is the pop-off pressure of the needle valve. Incorrect pop-off pressure might account for this behavior. This pressure can usually be adjusted by either changing the spring or by bending the needle lever.
> >
> > https://www.google.com/search?sxsrf=ALeKk007fCHWuhEPxpQiyvhLPQZ-WMZCmQ%3A1584835532804&source=hp&ei=zKt2XonHLtj4-wSDgrmoCA&q=carb+pop+off+tester&oq=carb+pop&gs_l=psy-ab.3.2.0l8j0i22i30l2.2146.4148..8689...2.0...0.132 .905.1j7......0....1..gws-wiz.....10..35i362i39j35i39j0i273j0i131j0i67j0i20i 263j0i131i67j0i10.f9GczK9WkxE
> >
> > Tom
>
> I'd never heard of the "pop off" pressure test. The 5 year inspection schedule for the original 2350 requires a pressure test of 0.4 bar (~ 6psi) allowed to decrease by 0.1 bar/min. https://aircraft.solo.global/img/cms/pdfs/Sonderkontrolle-2350_012015_Englisch.pdf
> Both of the carbys on our 2350D met this requirement indicating the needle & seat are ok. I'll report the outcome of fault finding, but it could be a few weeks. Rgds, Bill

This is the carb pop-off pressure test.

[Dan Marotta]

At only $3 or $4 each, I'd definitely change the spark plugs.

And, going back about 50 years or so when I was a radio technician in
the Air Force (before I got my EE degree), a megger or a mega-ohm meter
was, at the time, a hand cranked device used to measure very high
resistance in a circuit.Â* I never saw a reasonable use for one other
than charging up a very large capacitor and tossing it to a buddy,
hoping he'd catch it.

Spark plugs have an air gap, as you know, and I don't believe using a
megger is a worthwhile test to save $10 or so.Â* Buy new plugs.

On 3/29/2020 4:49 PM, BillT wrote:
> On Wednesday, March 25, 2020 at 12:31:27 PM UTC+11, Mike N. wrote:
>> I'll call Seminole tomorrow and see if they can troubleshoot.
>>
>> I am also thinking about getting the pump rebuild lots mentioned earlier in the thread.
>>
>> Thanks
> I spent a couple of hours Saturday checking suggestions from this group & others. Electrical - a friend put a megga on the spark plugs & tells they're ok. Checked ignition module secondary for continuity - both ok, checked the terminal block on the engine bay firewall for loose connections - all good.
> Fuel - removed the pulse line from the diaphragm pump & connected a syringe - it pumped ok. Checked carby inlets & exhaust for blockage (mud wasp nests) - all clear. I've ordered Carby diaphragms, gaskets & metering modules from SH so it may be a few weeks before these are installed. Next problem will be getting a launch to test fly - probably no operations due Cov 19. Rgds, Bill

--
Dan, 5J

[Charlie M. (UH & 002 owner/pilot)]

Plugs (I use NGK copper/V power) or wires/coils. A COP or extended plug wire into a well....look for carbon tracks from spark wire to ground....most noticeable at higher combustion loads (higher RPM's in NA, higher boosted in SC/turbo engines)....HV charge goes easiest path....higher combustion pressure sorta insulates spark going across plug gap....spark goes easy way....
Damp ignition can make misfires....so a damp day can make issues vs. a dry day....
Dielectric insulation of ambient air at seal level, standard pressure, is a lot lower than high compression/high load NA or "force fed"..
Physics son.....physics.....

[SoaringXCellence]

Just saw this on Reddit, looks like it might apply:

"Once I spent an entire weekend trouble-shooting an EX500 (twin cylinder Kawasaki) that would only run on one cylinder. The spark plugs, the float levels, the carb jets, the wiring harness, all connections, even checked the valve clearance and inspected all the valvegear.

Turns out an ant had crawled up a carb vent tube and wedged his tiny little body in just the right place in one little vent tube in one of the carbs. This mighty insect brought 600+ pounds of machine and man to a dead stop for an entire weekend. By weight, that would be like me stopping a cruise ship."

[BillT]

On Tuesday, March 31, 2020 at 9:08:25 AM UTC+11, SoaringXCellence wrote:
> Just saw this on Reddit, looks like it might apply:
>
> "Once I spent an entire weekend trouble-shooting an EX500 (twin cylinder Kawasaki) that would only run on one cylinder. The spark plugs, the float levels, the carb jets, the wiring harness, all connections, even checked the valve clearance and inspected all the valvegear.
>
> Turns out an ant had crawled up a carb vent tube and wedged his tiny little body in just the right place in one little vent tube in one of the carbs.. This mighty insect brought 600+ pounds of machine and man to a dead stop for an entire weekend. By weight, that would be like me stopping a cruise ship."

Thanks for the suggestions. I have bought new spark plugs (NGK B7HS) & will fit them for the next test flight. We tested the existing plugs (I won't call them old - they'd only run for 15') hoping we'd find one faulty - covering all possibilities. Rgds, Bill

[Dan Marotta]

Charlie reminds me:Â* I had a new Ford pickup back in the 80s and, while
still under warranty, it started running roughly.Â* The dealer was unable
to find a problem until they closed the roll up door on their garage and
then, in the reduced light, they could see one of the spark plug wires
arcing to the engine block.

Maybe replacing the spark plug wires is also a good idea.

On 3/30/2020 1:36 PM, Charlie M. (UH & 002 owner/pilot) wrote:
> Plugs (I use NGK copper/V power) or wires/coils. A COP or extended plug wire into a well....look for carbon tracks from spark wire to ground....most noticeable at higher combustion loads (higher RPM's in NA, higher boosted in SC/turbo engines)....HV charge goes easiest path....higher combustion pressure sorta insulates spark going across plug gap....spark goes easy way....
> Damp ignition can make misfires....so a damp day can make issues vs. a dry day....
> Dielectric insulation of ambient air at seal level, standard pressure, is a lot lower than high compression/high load NA or "force fed"..
> Physics son.....physics.....

--
Dan, 5J

[[email protected]]

On Monday, March 30, 2020 at 6:56:11 PM UTC-4, BillT wrote:
> On Tuesday, March 31, 2020 at 9:08:25 AM UTC+11, SoaringXCellence wrote:
> > Just saw this on Reddit, looks like it might apply:
> >
> > "Once I spent an entire weekend trouble-shooting an EX500 (twin cylinder Kawasaki) that would only run on one cylinder. The spark plugs, the float levels, the carb jets, the wiring harness, all connections, even checked the valve clearance and inspected all the valvegear.
> >
> > Turns out an ant had crawled up a carb vent tube and wedged his tiny little body in just the right place in one little vent tube in one of the carbs. This mighty insect brought 600+ pounds of machine and man to a dead stop for an entire weekend. By weight, that would be like me stopping a cruise ship."
>
> Thanks for the suggestions. I have bought new spark plugs (NGK B7HS) & will fit them for the next test flight. We tested the existing plugs (I won't call them old - they'd only run for 15') hoping we'd find one faulty - covering all possibilities. Rgds, Bill

If it is the pump I replaced mine on a Ventus CM (same engine block) with a Mikuni part no 14-2220 from Parker Yamaha in AZ for $18.42 in 2005 and it still works great 100+ engine hrs. later.

1MD

[BillT]

On Tuesday, March 31, 2020 at 1:09:31 PM UTC+11, wrote:
> On Monday, March 30, 2020 at 6:56:11 PM UTC-4, BillT wrote:
> > On Tuesday, March 31, 2020 at 9:08:25 AM UTC+11, SoaringXCellence wrote:
> > > Just saw this on Reddit, looks like it might apply:
> > >
> > > "Once I spent an entire weekend trouble-shooting an EX500 (twin cylinder Kawasaki) that would only run on one cylinder. The spark plugs, the float levels, the carb jets, the wiring harness, all connections, even checked the valve clearance and inspected all the valvegear.
> > >
> > > Turns out an ant had crawled up a carb vent tube and wedged his tiny little body in just the right place in one little vent tube in one of the carbs. This mighty insect brought 600+ pounds of machine and man to a dead stop for an entire weekend. By weight, that would be like me stopping a cruise ship."
> >
> > Thanks for the suggestions. I have bought new spark plugs (NGK B7HS) & will fit them for the next test flight. We tested the existing plugs (I won't call them old - they'd only run for 15') hoping we'd find one faulty - covering all possibilities. Rgds, Bill
>
> If it is the pump I replaced mine on a Ventus CM (same engine block) with a Mikuni part no 14-2220 from Parker Yamaha in AZ for $18.42 in 2005 and it still works great 100+ engine hrs. later.
>
> 1MD

Apologies for the delay in reporting progress on this (many delays due Covid). Fitting the Walbro carburettor parts, (consisting of the diaphragms, gaskets and metering modules) ordered from SH, resolved the problem. The engine is now starting immediately and producing full power.
There was one hiccup however – initially the engine would start, run for 5 – 6 seconds, cut and then immediately restart. This would occur 6 – 7 times before stabilizing and producing continuous full power. After much deliberation it was realised the drive belts were slipping, causing the engine to over speed and the rev limiter to cut the ignition. Re-tensioning the belts solved this. Regards, Bill

[2G]

On Saturday, July 4, 2020 at 11:53:07 PM UTC-7, BillT wrote:
> On Tuesday, March 31, 2020 at 1:09:31 PM UTC+11, wrote:
> > On Monday, March 30, 2020 at 6:56:11 PM UTC-4, BillT wrote:
> > > On Tuesday, March 31, 2020 at 9:08:25 AM UTC+11, SoaringXCellence wrote:
> > > > Just saw this on Reddit, looks like it might apply:
> > > >
> > > > "Once I spent an entire weekend trouble-shooting an EX500 (twin cylinder Kawasaki) that would only run on one cylinder. The spark plugs, the float levels, the carb jets, the wiring harness, all connections, even checked the valve clearance and inspected all the valvegear.
> > > >
> > > > Turns out an ant had crawled up a carb vent tube and wedged his tiny little body in just the right place in one little vent tube in one of the carbs. This mighty insect brought 600+ pounds of machine and man to a dead stop for an entire weekend. By weight, that would be like me stopping a cruise ship."
> > >
> > > Thanks for the suggestions. I have bought new spark plugs (NGK B7HS) & will fit them for the next test flight. We tested the existing plugs (I won't call them old - they'd only run for 15') hoping we'd find one faulty - covering all possibilities. Rgds, Bill
> >
> > If it is the pump I replaced mine on a Ventus CM (same engine block) with a Mikuni part no 14-2220 from Parker Yamaha in AZ for $18.42 in 2005 and it still works great 100+ engine hrs. later.
> >
> > 1MD
>
> Apologies for the delay in reporting progress on this (many delays due Covid). Fitting the Walbro carburettor parts, (consisting of the diaphragms, gaskets and metering modules) ordered from SH, resolved the problem. The engine is now starting immediately and producing full power.
> There was one hiccup however – initially the engine would start, run for 5 – 6 seconds, cut and then immediately restart. This would occur 6 – 7 times before stabilizing and producing continuous full power. After much deliberation it was realised the drive belts were slipping, causing the engine to over speed and the rev limiter to cut the ignition. Re-tensioning the belts solved this. Regards, Bill

Sounds like you have just passed your final for your AA degree in small engine repair. Congrats!

Tom