140 mercarb issue

[tacittern]

Hello,

Is is critical as far was what RPM I should set the Idle, since I dont have a working tach. and same question about the idle mixture. Should that be set after setting the idle?

When I accelerate up to WOT after about 5 seconds the engine completely falters and begins to stall out and will only continue to run when I back off the throttle. The bowl seems to be completely running out of fuel. I have set the drop and the level to the specs in the rebuild kit but I noticed when I readjusted them from the first time that I set them incorectly it has actually run worse. I had the level slightly too high by 1mm and the drop was way off by 10 mm or so (what ever the distance is between the marking dots on float). So I lowered it that much.

I'm going to pull the plugs and see what condition they are in tomorrow this will tell me if it is running lean. Then I guess I can just start raising the level slightly and the drop as well. 1986 mercarb 140

 

[Limited-Time]

Re: 140 mercarb issue

Try running on s remote fuel tank.................that will tell you if its a carb or fuel supply issue.

 

[supercab78]

Re: 140 mercarb issue

Adjust your mixture screw first, then set idle speed. then readjust mixture screw to reach highest idle. Then lower or raise idle speed as needed. Since you don't have tach this may help, about the slowest my 140 will idle is 500 rpm, I think you want 650 rpm. So maybe raise it up a little from the slowest rpm it will idle. When you installed you needle & seat did you use the spring and pin or just he solid pin in the needle? I'm assuming your kit came with both options.

 

[freak007]

Re: 140 mercarb issue

whats the float spec in the rebuild kit? There are multiple service bulletins that differ from the original manual spec...

What is the # on the carb?
Engine serial number?

 

[tacittern]

Re: 140 mercarb issue

I have the solid type needle. My float setting is 10mm and the drop is set at 27mm. Carb is 1389-9350 and engine is 140 s/n A653829