Problem after WOT

[DutchMerc]

I have a '74 Mercury 402 and it seems to run fine at WOT. When I slow down after running it for a few minutes at WOT, it seem to stall and even almost stops when i don't open the throttle quickly. The plugs are new, and so is the switchbox. Carbs are cleaned recently, and the fuel is fresh. Any ideas what to check?

 

[j_martin]

Re: Problem after WOT

Could be running lean, and trying to seize up.

 

[DutchMerc]

Re: Problem after WOT

Could be running lean, and trying to seize up.

So, should I ad more oil? I mixed it 1:50, this should be O.K. I think? The motortemperature looks fine to me, warm, but not verry hot...

 

[j_martin]

Re: Problem after WOT

So, should I ad more oil? I mixed it 1:50, this should be O.K. I think? The motortemperature looks fine to me, warm, but not verry hot...

Actually, more oil will make it run leaner. Lean refers to the fuel to air ratio. Not enough fuel runs hot and causes trouble. 2 cycle engines like to be a bit rich from peak performance or they will burn pistons. The temp to worry about is at the pistons, and need not overheat the water.

More oil will make it run leaner because it makes the fuel thicker so it doesn't go through the measuring jets as fast.

 

[DutchMerc]

Re: Problem after WOT

Any ideas how to solve this problem? On my carb there is only one screw, wich is for the idle-speed. Should i change this setting, or can timing have anything to do with it?