Idles then dont

[Paradise pontoon]

Have 150 Johnson 1984. Runs great and ildes fine for a few seconds then dies. Rebuilt carbs. Have removed oil injection system so running mixed fuel. Run great last couple of years until carbs gummed up. But never really idle very well back then either. New fuel lines fuel filters. New primer bulb. Running electric fuel pump seems to pumping good. Even pulled the pickup tube from fuel tank and checked it good shape no leaks. So tell me when you mix fuel on a system that use not be was oil injection would you need to change idle orifices on carb to larger ? Ok find it has 33 idle jets in my carbs. Johnson offers a 34 jet only the 33 are unavailable Thinking about trying those the 34
Thanks
Mike

 

[racerone]

No need to chage carburetor parts.----Post the actual compression values on this motor.----Does spark jump a gap of 3/8" using a test device?

 

[Paradise pontoon]

No need to chage carburetor parts.----Post the actual compression values on this motor.----Does spark jump a gap of 3/8" using a test device?

Motor has 120 compression on all cylinders. Has new plug wires and plugs. Yes it jumps that and more.
Thanks

 

[saltchuckmatt]

OEM parts?

What rpm are you setting it to?

In gear and under load?

 

[Paradise pontoon]

M

OEM parts?

What rpm are you setting it to?

In gear and under load?

yes all oem parts . 750-800 in the water no load

 

[saltchuckmatt]

M

yes all oem parts . 750-800 in the water no load

Should be set higher than that if there's no load. Possibly could be your problem.

 

[Paradise pontoon]

Should be set higher than that if there's no load. Possibly could be your problem.

Ok tried around 1000 idle. Still the same thing. Like i was saying it will idle for a sec or 2 then dies. If i keep hitting the choke right before stalls it will go back up to idle speed. Well run fine at full throttle. So not thinking fuel problems but idle acts like fuel problem.

 

[saltchuckmatt]

Ok tried around 1000 idle. Still the same thing. Like i was saying it will idle for a sec or 2 then dies. If i keep hitting the choke right before stalls it will go back up to idle speed. Well run fine at full throttle. So not thinking fuel problems but idle acts like fuel problem.

Fuel issue, low idle circuit.

Full speed that circuit is bypassed and run though the main jet.

You most likely missed something cleaning the carbs.

 

[Paradise pontoon]

Fuel issue, low idle circuit.

Full speed that circuit is bypassed and run though the main jet.

You most likely missed something cleaning the carbs.

Yes you probably right. Ill go back through them and see

 

[Jeff J]

Not familiar with this particular carb. Generally speaking, idle is too lean if choke brings it back. A fuel passage is likely partially blocked or the mixture needs enriching. Could also be an air leak.

 

[Paradise pontoon]

Not familiar with this particular carb. Generally speaking, idle is too lean if choke brings it back. A fuel passage is likely partially blocked or the mixture needs enriching. Could also be an air leak.

Thanks for the help, thats one of the problems with this style of carb no adjustments on carbs. I went back through the carbs again, will try starting it this morning.
Thanks again