Cylinder not all working ?

[Pat20201]

Hey guys. Since this year I have the following issue.
searay Sundancer 250 - 1997

last year the boat started to go in gliding at 3500 rpm
And this year at 4500 rpm. So my idea is that not all cylinders are working well. how can I check that ? Or does someone know if it’s maybe something different?

thanks patrick

 

[Lazy Daze]

Can you still reach the same top speed and max RPM (around 4,800)? How's your fuel quality and hull bottom/running gear cleanliness? When's the last time you changed (and dumped into a jar to check quality) the fuel filter?

But a compression test can be done to check further check things out.

 

[Pat20201]

The boat just came out of service. so the Motor was checked
Max rpm was around 5400 i would say. Need to check that again.

 

[Pat20201]

Anyone knows when gliding normally starts ?

 

[Lazy Daze]

Somewhere in that low to mid 3,000 range depending on conditions and engine/tab use. But you already know this since you did it last year - that part won't change.

What does "The boat just came out of service. so the Motor was checked" mean? What exactly did they service and what exactly did they "check"? Did they do a compression test?

What about the other questions?

Been waiting for those answers!