Power loss in Suzuki 4 stroke at top end.

[Papa Joe]

Any suggestions on how to solve a lack of power at top end of 4 stroke Suzuki on our tender. The engine is 10 years old but until now has been most reliable. It starts fine, runs beautifully and sips fuel. The engine has been serviced annually, eg., new impeller, new plugs, oil changed in lower unit, fuel filters etc. Crankcase oil and filter changed every 100 hours and until this year would plane the tender with no problem. If you've had this happen what was the solution to the dilema.

[fgd3]

When was the last time you checked the valve clearance?

Fabbian

[Cheechako]

Two possibilities. The hub on your prop is spun. (had that happen with the same identical symptoms) The main bearings are shot (had that happen and the engine wouldnt rev up as high as it did, had more vibration too)

[fgd3]

Originally Posted by Cheechako

Two possibilities. The hub on your prop is spun. (had that happen with the same identical symptoms) The main bearings are shot (had that happen and the engine wouldnt rev up as high as it did, had more vibration too)

Won't the engine over-rev if the prop hub slips?

Fabbian

[Cheechako]

It might over rev some... but the boat wont plane well or not at all if loaded.

[Papa Joe]

I'll check all of the above and will keep you posted on the results. Many thanks to all.

[bobconnie]

What type of fuel did you buy last time ???? could be that darn alcohol doing it's majic ! just a thought

[perchance]

Low compression, ignition timing, a partially plugged high speed jet or a weak fuel pump are a few possibilities that come to mind.