Miss in F40, 2004

[newf1]

I have a miss in my F40 4 stroke. While at 3/4 to full throttle after running for a few minutes I get a miss in the engine. It only hapens once and a while and sometimes worse then others as if the engine dies for a split second. I already had it in yesterday for a carb cleaning and it is still doing it.

Could this be electrical? I was doing it before the cleaning as well. Any thoughts or ideas?

Also, what shoud be the RPM at WOT. I got 6000 with a 11.5 pitch @ 27-28mph.

 

[newf1]

Re: Miss in F40, 2004

Update.

The dealer checked all the coils/CDI/ connections all checked out good. They took it for a water test and found it still missed once warmed up. The carbs were clean.

They noted that the problem was with the #1 cylinder consistantle even when changing the coils sround and with a new CDI.

Could this cylinder be bad and missing occasionally once heated up?

Thanks

 

[Moose1am]

Re: Miss in F40, 2004

Not sure what's wrong with your motor. I talked to a friend yesterday and he has a 40 hp Yamaha 4 stroke engine that he has had for about 3 years. He was unsure of exactly how old the motor is for some strange reason. I told him about Iboats and recommended that he ask the question in here. But he is not familiar with computers and didn't know how to go about asking questions in here.

I told him that I would check in here to see if I could find out anything for him.

His motor seems to run find at idle and at full speed. He also has three cylinders.

He purchased this motor at this dealer at the main entrance to Patoka Lake in Southern IN. He has taken the motor in for warranty service three times so far and they can't get it fixed.

It misses and runs bad at around 3/4 throttle.

I suspect it's something electrical as the fuel is getting there at idle speed and at full throttle.

He said that it maybe a needle value in the carb.

I am looking for any information that can help my friend get his motor running smooth though all ranges. He paid over $6000 for this motor.

He works part time for the IN DNR and it's embarrassing to have guesses seeing this motor not working properly.