My OS 75ax...when I run it wide open and stay in the throttle for awhile...it wants to shut off....sometimes if I can tell its gonna happen I can back off the throttle and it recovers fine...but sometimes it shuts off. I dont think it is running to lean, it blows plenty of smoke and excess fuel comes out of the exhaust and the engine stays nice andcool. Could it be running to rich and when its wide open be dumping too much fuel to burn and be loading up? Do I need to mess with my low speed needle? Or high speed needle? Run it richer or more lean? It is running great but like I said....if you stay in the throttle for a long stretch it tends to want to die out and shut off. Any help would be appreciated.

check your gap in the plug

its a glow plug. is there a gap?

How much of a gap do I need?

Stop messing with the new guy....that's just mean. LOL.

"bench" run it to full throttle, watch the tank and fuel lines for bubbles. I have a hunch that vibration is causing fuel foam at high rpm and causing a lean condition.

If it looks like this, you have a problem:

http://s68.photobucket.com/albums/i2...t=MOV03864.mp4

Yea that is funny..lol...next thing you know I will be checking the muffler bearings or the fitzer valve!! But I think you are exactly right about the fuel foam...it does do that cause it did the same thing on my FWC boat. How do I stop it.....rubber bushings between the tank and where it mounts at?</p>

u get the prop balanced yet? u may have to change the reverb valve lmao

I'll tell ya'.....I had the prop balanced to a "T", isolated the tank from the stand with foam and if you look closely at the boat in the video, completely isolated the engine from the tank stand.

It still foamed the fuel. I had to graduate to a [link=http://www.centralhobbies.com/Fuel/fueltnk2.html]Tettra bubbless tank.[/link]

How do the bubbless tanks work Crispy ? ...interesting

 I used a 1/2 inch thick foam pad for mine, and it worked fine.

They work by first removing all the air from the fuel using an internal bladder. Exhaust pressure pushes against bladder cause fuel to flow. No air in the tank.... no issues with air bubble. I've used both Tettra and Jett and perfer the Tettra.

Thanks Andy. Couldn't have said it better myself.

Thanks for all the Help crispy and asmith....BBG(not so much) lol, I will prob order one of these for sure. Ran it on the bench and bubbles like crazy and I bet it tends to get worse especially when the is almost empty leaving nothing but bubbles. Does this tank have any mounting tabs...it was hard to tell in the pics?

Nope, no mounting tabs. I used zip ties and double sided servo tape to keep it in place.