carb setting for a 1992 8hp Yamaha please

[vickaczynski]

My son bought a '92 Yamaha 8 hp that has been sitting in a garage for 4 years, no owners manual. Cleaned and set the plugs (which were not bad). fresh gas and oil, 50 to 1 (is this correct for this year)? Could not start except with starter fluid which only lasted a few seconds. Gave it several shots of Gumout. Let it sit overnite. Started and ran the next morning but only with choke out. Water pump appears good. Gave it several more shots of Gumout while it was running. Still only ran on full choke. More shots of gumout. Same result. Checked the only needle valve I could find. It was set at 2 1/4 turns. Played with this 1/8 turn at a time. Finally got it to run for a brief time on no choke but not for long. So what is the suggested setting for the needle valve? Thanks for any help. Vic/

 

[Silvertip]

Re: carb setting for a 1992 8hp Yamaha please

You can stop worrying about carb settings. The engine sat for four years and the carb is gummed up internally. Spraying cleaners through the carb throat does absolutely nothing except clean the throat. It needs to be disassembled, soaked in carb cleaner, every passage cleaned thoroughly and then reassembled with a new kit. Before disassembly, turn the mixture screw in and count the turns required to seat it lightly. Set the float level. In the future, run SeaFoam in the fuel to keep the fuel system clean and always use fresh fuel. DO NOT use starting fluid. There is no lubrication in it. You can damage the engine using that stuff. After the carb is rebuilt, initially set the idle mixture screw to the number of turns out you counted earlier. Start the engine and turn the screw in until the engine begins to die. Turn it back out until it begins to die. Happiness is somewhere in between those two settings.

 

[deejaycee_2000]

Re: carb setting for a 1992 8hp Yamaha please

I agree with Silvertip, you will definately need to clean that carb properly, just spraying cleaners would not clean it the way it should be ....

 

[rodbolt]

Re: carb setting for a 1992 8hp Yamaha please

actually on a two stroke already running lean carb cleaner and starting fluids do a lot more than just clean the carb venturi, its time to dissasemble and clean the carb,
on that model I believe the only thing the needle does is adjust how much of the pilot air and pilot fuel pass the throttle shutter.
its old enough I cannot remember offhand but most yamaha carbs DO not adjust air to fuel by a mixture needle.