Bad hesitation at 1200 rpm

[Aviator04]

Hey guys, my 2005 3.0 tks has a bad hesitation at 1200rpm only. It idles smooth and will run on plane all day long but just that one spot in the rpm range it falls on its face. Not that it should be related but I recently had to pull the engine to replace the starter and flywheel. New plugs, filter, fresh gas. This thing is breaking my soul. Any suggestions? Thank you

 

[alldodge]

Initial thought is the power valve has an issue

Is the accelerator pump rod in the middle hole?

 

[Scott06]

Do you get a good accelerator pump shot? Would be thinking the of idle or transition circuit may be clogged. Given the age might be worth rebuilding setting float level etc

Have you tried adjusting idle mix screw out (richer) to see if it smooths this out? Willing to bet at factory they were set on lean side

What does your fuel filter look like ?

 

[Aviator04]

Thanks will check those items out. Accelerator pump looked to squirt good, however I don’t have much experience working with carbs. I’m going to check the mixture screw. Question; If I adjust mixture screw in gear in water, should I be at idle speed or a bit higher?

 

[Bondo]

Thanks will check those items out. Accelerator pump looked to squirt good, however I don’t have much experience working with carbs. I’m going to check the mixture screw. Question; If I adjust mixture screw in gear in water, should I be at idle speed or a bit higher?

Ayuh,..... It shouldn't matter,......
It's the idle speed screw that you set "in the water, at idle, in-gear, to set the idle speed,....
Most want 650 / 700 rpms,.....

 

[Aviator04]

Initial thought is the power valve has an issue

Is the accelerator pump rod in the middle hole?

Will check that out. It needs to be in middle hole?

 

[Aviator04]

Ayuh,..... It shouldn't matter,......
It's the idle speed screw that you set "in the water, at idle, in-gear, to set the idle speed,....
Most want 650 / 700 rpms,.....

Ok gotcha, so can I technically adjust the mixture screw while running on muffs or better to do in water?

 

[alldodge]

Will check that out. It needs to be in middle hole?

Doesn't have to be, but that is where it normally is placed. Just want to know where it is now. The accelerator pump can be moved if more fuel is needed.

The power valve is what is used to transition from just above idle to more power.