What feels like a slipping transmission?

[tyrrhena]

OK. Back in business with my 27 year old merc 170 after voltage regulator died. Put in water today for the first time since, and it felt like the equivalent of an automobile with a tranny problem... From 700-2200 RPM or so, it ran fine... At about 2400 RPM it felt like the gears were slipping some....the engine was trying too hard to engage... I can't explain it just right... In throttle only mode, she purrs like a kitten at all RPMs...only when she is load bearing and above 2200 rpm do we notice this issue. Forgive my long windedness, but trying to best describe it...

 

[thumpar]

Re: What feels like a slipping transmission?

Sounds like a spun prop hub. Could be a coupler but those usually smell and completely go pretty quick. Any overheat issue?

 

[tyrrhena]

Re: What feels like a slipping transmission?

All gauges reading normal the whole time... (No overheat smell either) The boat has only been in the water a few times this year. Last year ran like a champion... Today was the first day this year I tried to open her up (on a lake finally). Normally she is run at cruising speeds in a small river/canal or when gramma is on it with my kids...

 

[Bob_VT]

Re: What feels like a slipping transmission?

Check your prop!

 

[bonzoscott]

Re: What feels like a slipping transmission?

OK. Back in business with my 27 year old merc 170 after voltage regulator died. Put in water today for the first time since, and it felt like the equivalent of an automobile with a tranny problem... From 700-2200 RPM or so, it ran fine... At about 2400 RPM it felt like the gears were slipping some....the engine was trying too hard to engage... I can't explain it just right... In throttle only mode, she purrs like a kitten at all RPMs...only when she is load bearing and above 2200 rpm do we notice this issue. Forgive my long windedness, but trying to best describe it...

Welcome to iboats! Other guys have thought a spun prop is what you have. You can check that by scribing a mark on the hub across the damper, drive the boat, inspect your mark and see if it is mis-aligned. But I'm not sure by your description and the words trying too hard. Spun prop would be like a slipping clutch and the motor Revs high.