Yam 2.5 hp 4 stroke carburation problem

PBoteler

Recruit
Joined
Aug 26, 2007
Messages
1
Help, please.

My engine has not been run for several months, but ran very well beforehand.

Problem: The engine now runs as if the choke is half closed ? no revs, blue smoke, black, oily plug. With the air filter removed, large droplets of gas can be seen coming out of the main jet.

The engine will run at normal/high revs if, a) the intake manifold bolts are loosened and additional air is allowed into the manifold, or, b) the fuel **** is closed; then, just at the point of fuel starvation, the gas coming through the main jet turns into a fine spray and she starts singing ? for 4 to 5 secs..

It seemed like typical flooding of the carb due to a sticky float/needle assembly. But, being aware of the critical nature of the oil level, I first lowered it to the minimum and ran the engine for a while with no improvement.

All normal procedures that I can think of have been tried ? full breakdown, jets cleaned, float assembly cleaned and polished, manifold gaskets matched and sealed, intake air filter washed, cleaned and dried, fuel tank and lines cleaned, dried and replenished ? even took the carb to my local outboard expert who declared it ?good to go?. But, it don?t go.

Any suggestions would be very much appreciated.
 
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