susuki140 rpm spike

[lenster]

I have a susuki 140hp and when i reach 3000 rpms the rpms spike up to 6000 immediately even though i dont throttle up any. I then throttle back and when i hit 3000 rpms again it the rpms spike again (its like it goes in to neutral when it hits 3000 rpm). also when i am running at low speed (parking in the marina) the engine spits and sputters and will sometimes stop running. Any suggestions for these problems? Thanks.

 

[steelespike]

Re: susuki140 rpm spike

The RPM "Spike"Sounds like a spun hub sometiomes when a hub starts to fail it will spin as throttle is increased as time goes by it will happen at lower and lower rpm.
Spun hub can be repaired at a prop shop.If you want to test draw a line across the under side of the hub with a paint marker, test the boat and check the mark.
Could also be simple ventilation.Prop gets air bound.Is the prop in excellent shape?
You don't say what year motor,2 stroke or 4.As far as the idle it could be as simple as the idle speed set too low,700 to 750 is usual. or The pilot air screws may need to be set. Or any number of less obvious problems could be at work.