GP42 Engine

[Keat]

Guys.

 

I recently bought a used low wing trainer, which came with a GP42 engine.

The engine sounds rough at low revs, but sweet on full chat.

I also can't get it to tickover nicely.. I've changed the plug, and flushhed he tank incase of any old residual fuel.

The crank shaft has tons of end float, wheras my other 2 engines have no end float what so ever.

Can this end float be the cause of my problems, and would I need to shim it out ?

Edited By Keat on 02/08/2009 09:53:50

[Keat]

Folks

 

I think i may have fixed it.

 

I stripped the engine and checked the bearings for excessive wear. To be honest, I was really surpised how clean it was inside. The Piston top doesn't look like it's done a great deal

On Reassembly I replced  the rear cover gasket with a new homemade one.

Both carb screws were lazy, not really tightening up, so I made a new carb gasket and replaced the screws with a few small self tappers.

And replaced the fuel hoses.

 

Although it now ran a lot better, it still rattled like a can or marbles on low revs.

 

In the end I had nothing to lose really, either try and fix it, or chuck it in the bin.

 

So I skimmed a little bit from the collar with the dremel, resulting in the collar being a little tighter against the shim.

The end float has gone from about 15 thou to maybe 1 or 2 thou. Still has a tiny little bit of end float/clearence.

Runs really sweet now.

I guess the correct way to do it, would be to add some shims, but as I don't have any and was prepared to chuck the engine anyway, I thought, what the heck.

 

I guess some people will frown, but rest assured, I'll be giving it some serious ground testing before it goes in the air.

Edited By Keat on 02/08/2009 22:24:19