Lost 700 rpm somewhere

Re: Lost 700 rpm somewhere

by Michael Regan » 13 years ago

Michael Regan

5 96 0

I installed the TinyTach this morning and so now have the 2 tacos both working.
When I test flew it the tinytach showed even more discrepency reading 100 rpm lower than the origonal tacho, and it showed only 5900 instead of 6700 max rpm. So at least I know now its not a faulty tacho.
Next step.... open her up... Thanks guys....Mike

Re: Lost 700 rpm somewhere

by Ian Jones » 13 years ago

Ian Jones

2 53 0

How about the needle jet circlip area wearing a bit? This would cause the needle jet to be positioned a little bit into the jet needle at full throttle, causing less fuel into the engine.

Pud

Re: Lost 700 rpm somewhere

by Nick Axworthy » 13 years ago

Nick Axworthy

16 325 0

So it looks like your original tach was not a 100 miles out indicating 200 over...if I read that right,

At least you know where your working now.

Re: Lost 700 rpm somewhere

by bill martin » 13 years ago

bill martin

10 757 0

mike,

You can't see the rings from the carb side. You'll have to look from the exhaust side. Before you pull the exhaust manifold, I would check the compression. If both cylinders are very nearly the same, you probably don't have a ring problem. If you do inspect the rings, the clearance in the lands is so small that it is hard to tell if the ring is stuck or not. A trick I use is to smear a generous amount of oil on the visible portion of the rings and rock the crank up and down just enough to barely move the piston. If the rings are free, you can see the oil squeezing in and out between the rings and the land. Also check the cylinder walls for any signs of scoring or aluminum smearing. You may see what looks like two vertical score lines on the back side of the cylinder about an inch apart. Those lines are where the ring ends are located and are not usually a problem.

How about prop pitch? any changes there that would have caused the RPM drop?

Bill.

Re: Lost 700 rpm somewhere

by bill martin » 13 years ago

bill martin

10 757 0

Mike,

I forgot to ask. How about EGTs? are they pretty much equal in both cylinders. Could be a carb problem.

Bill.