Engine stumble folowup

OK..

By "feel" there is a little looseness in the throttle valve
bushings in the carb.. we gona look further.

Thanks to all for some great thoughts/solutions.

Can anybody suggest some tests to confirm an intake system
leak that allows excess low DA air to lean the mix when the throttle
valve closes rapidly at high engine RPM?

What clearance should there be in the Throttle Valve bushings?
(if any)

Dave

Arrrrughhh!

Flew today, -5C as opposed to -8C...

Could not get it to stumble on throt retard.. Rich, lean, VERY lean,
Rt tank,Lt tank, Pump on/off.

I don't know whether to be disappointed or elated.

Looks like I gotta fly it some more...

Dave

On Sat, 10 Dec 2005 13:26:29 -0400, Dave
wrote:

OK..

By "feel" there is a little looseness in the throttle valve
bushings in the carb.. we gona look further.

Thanks to all for some great thoughts/solutions.

Can anybody suggest some tests to confirm an intake system
leak that allows excess low DA air to lean the mix when the throttle
valve closes rapidly at high engine RPM?

What clearance should there be in the Throttle Valve bushings?
(if any)

Dave

Dave,

There should NOT be any perceivable movement (side-to-side) in the
throttle shaft whatsoever, IDEALLY!

Best way to test for intake leaks is to use some sort of carb spray or
possibly WD-40. Lokk ofr a decrease in engine speed or stumbling ...
while on the ground, of course!

Have fun!

Dave wrote:
Arrrrughhh!

Flew today, -5C as opposed to -8C...

Could not get it to stumble on throt retard.. Rich, lean, VERY lean,
Rt tank,Lt tank, Pump on/off.

I don't know whether to be disappointed or elated.

Looks like I gotta fly it some more...

Dave

On Sat, 10 Dec 2005 13:26:29 -0400, Dave
wrote:

OK..

By "feel" there is a little looseness in the throttle valve
bushings in the carb.. we gona look further.

Thanks to all for some great thoughts/solutions.

Can anybody suggest some tests to confirm an intake system
leak that allows excess low DA air to lean the mix when the throttle
valve closes rapidly at high engine RPM?

What clearance should there be in the Throttle Valve bushings?
(if any)

Dave

Movement is very slight, up & down, none horizontally...

Than would be somewhat ... ummm.. interesting, with the propeller
spinning nearby...

Dave


On 12 Dec 2005 21:46:13 -0800, wrote:

Dave,

There should NOT be any perceivable movement (side-to-side) in the
throttle shaft whatsoever, IDEALLY!

Best way to test for intake leaks is to use some sort of carb spray or
possibly WD-40. Lokk ofr a decrease in engine speed or stumbling ...
while on the ground, of course!

Have fun!

Dave wrote:
Arrrrughhh!

Flew today, -5C as opposed to -8C...

Could not get it to stumble on throt retard.. Rich, lean, VERY lean,
Rt tank,Lt tank, Pump on/off.

I don't know whether to be disappointed or elated.

Looks like I gotta fly it some more...

Dave

On Sat, 10 Dec 2005 13:26:29 -0400, Dave
wrote:

OK..

By "feel" there is a little looseness in the throttle valve
bushings in the carb.. we gona look further.

Thanks to all for some great thoughts/solutions.

Can anybody suggest some tests to confirm an intake system
leak that allows excess low DA air to lean the mix when the throttle
valve closes rapidly at high engine RPM?

What clearance should there be in the Throttle Valve bushings?
(if any)

Dave