Yamaha F40 2008 running bad

[pettereg]

Hi,

My Yamaha F40, 40 horsepower.
It idels great also more than 3500rpm full power.
It runs bad between 2400-3500rpm.

What is the problem?

Best regards

Petter

 

[racerone]

Could be lots of things.----What are the maximum revs on your tachometer at full throttle on the boat ?----Changed filters ?----New sparkplugs?----Does spark jump a gap of 3/8" ( 1 cm ) on each lead ?

 

[pettereg]

Could be lots of things.----What are the maximum revs on your tachometer at full throttle on the boat ?----Changed filters ?----New sparkplugs?----Does spark jump a gap of 3/8" ( 1 cm ) on each lead ?

Hi thank you

Max 5900rpm, New spark plugs bought at Yamaha

 

[QBhoy]

Are you have on and half off the plane? Sorry to ask

 

[boscoe99]

Is that the F40B model?

 

[pettereg]

Er det F40 B - modeller?

Ja det er F40 B

Er det F40 B - modellen?

F 40 BET modell. Den er ok opp til 2500 rpm så snubler den, går dårlig opp til 3500rpm. Fra 3500 til maks går den utmerket. Det snubler helt til båten går i plan

 

[pettereg]

Ja det er F40 B

F 40 BET modell. Den er ok opp til 2500 rpm så snubler den, går dårlig opp til 3500rpm. Fra 3500 til maks går den utmerket. Det snubler helt til båten går i plan

It runs ok up til 2500 rpm more throttle it stumble, goes bad up to 3500 rpm. From 3500 rpm to Max it runs great. The engine stuble until the boat goes to plane.

 

[pettereg]

Are you have on and half off the plane? Sorry to ask

Hi , it stumble when it working to get into plane. When its in plane the enginge works great

 

[boscoe99]

My guess is that the carburetors need to be cleaned. The accelerator circuit and/or the mid range circuits may be malfunctioning.

 

[pettereg]

My guess is that the carburetors need to be cleaned. The accelerator circuit and/or the mid range circuits may be malfunctioning.

Thank you