"figurado" wrote in message
...

Thanks much for the responses.

I don't think the tach is sticking but it will be checked in a week
when it goes in to my local mechanic to deal with a few squawks.

I'm hoping the exhaust and shroud don't need an overhaul but I'll check
that also.

The testing was with the cowl on.

One thought is that the full rich position of carb is not rich enough.
Any thoughts?
--
figurado

One way to check the idle mixture is to set the RPM at 1,000 when full rich.
Slowly pull the mixture knob out while watching the tach. You should see a
25-50 RPM increase just before the engine dies. If you do not see the RPM
rise then you may be to lean and it should be checked. If there are any
doubts about the heater shroud and exhaust system in general get it checked
too, with winter coming on you will be using it.

Allen