Thanks for all the help and info, way to cold right now to mess with it.:<(

I've read this thread through and have the same problem with the 46 cutting out at full throttle. I've tried everything to fix this problem. New hose (no air bubbbles in the line) New plug, filter, cushioned the tank.... etc... The engine is tuned right. Did the pinch test and resolts are perfect. The engine idles fine and runs very well at 3/4 throttle. When I push to full throttle it cuts out. I can run the engine at a little over 3/4 and it runs for ever with out a problem. Only happens at full. Any one have any ideas?

I recently had two different engines with similiar problems... I was trying to help someone else out at the field.

In one case the person had the clunk just shy of contacting the back of the tank. This was well and good superficially, but when at the field it turned out that because of the angle of the plane, the clunk was actually contacting the back curved wall of the tank.

When this happened, you would get exactly as what you describe!

Why?

Well the clunk has a cutout that permits fuel to pull from the side, even though it was up against the tank wall.

However when the throttle was run fully up, the contanct with the back of the tank restricted the flow to the point that the engine cut out ONLY at high throttle... and it was fine all other times.

This drove me nuts looking for other issues.



The second case was similiar, ultimatly a fuel flow problem. One of the fuel lines was being pinched off INSIDE the plane, restricting flow at the higher rates.


If the engine passes the 3/4 throttle pinch test and you've eliminated carb leaks, etc. ( assuming you do not have too HOT of a plug on it as well... ) look "outside" the engine for the cause.

At worst, try hooking it up to a new tank that is outside the plane, and see if it runs that way.



One last note, are you SURE that the needles are not "walking" as you advance and retard the throttle?

The clunk sounds like it could be the problem. I noticed when I pulled the tank out today. The clunk fell all the way back to the far corner. I have a #8 plug in it. #8 works fine for my 3 other 46's. I put a zip tie on the niddle valve. Tightend it down just enough so you can adjust it but it won't walk. I'll shorten up the clunk line tomorrow and see if that works. Thanks for your help. This ones driving me nuts.

Don't be surprised that you might also need to retune the engine.

It will end up running a quite bit richer when you first start it up.

Be prepared for the high end still cutting out past transition, until you re-adjust it, then the top end cut-off should disappear.