60 HP Merc Big Foot higher RPM range

"I'm posting this for a la

"I'm posting this for a lady I know, she had recently bought a 21ft Pontoon with the mentioned motor on it, all was good for awhile (it's IIRC ) a 2004 Merc supposed to be very low hours on it. Runs great, but the other day she tells me at a bit over 4,000 RPMS it "revs up, RPMS rise but boat slows like you dropped the throttle back fast)

She has this boat on a nearby lake (no trailor) so taking it in to be checked will be a task.....she may be able to get someone qualified to look at it, but was hoping I might be able to find some knowledgeable folks here who could "warn" her of what it most likely is and the expense involved...

She ran the boat back in (about five miles she thinks) @ 3000-3200 RPM with NO hiccups at all, so I'm thinking it only does this (or did it) at higher RPMS (WOT runs about 5000-5500 RPM IIRC)

Thoughts? Opinions?

Thanks in advance for any input on this."

I would check the prop for a s

I would check the prop for a spun hub. With that toon she's not putting a lot of load on it. The rpm's would be lower if there was a good load on the motor. Here'show you check it pull the motor
up out of the water with a silver sharpie draw a good line from side of the prop hub to the other (across the nut) Next take the toon out for a run and run it hard wot close the the dock. Look for prop slip when you come back in the line will not line up. If it doesn't line up pull the prop and have it the hub a new pressed in.
I hope this helps post back what you find
Hamit

"Thank you very much, that sh

"Thank you very much, that should "ease her mind" I suspect. Not sure when we can get together to check that but sounds quite possible that you're "dead on" . With our work schedules it may be some time, but will post the results as soon as we have them!

Again many thanks, I knew we'd find some great folks here, who would be willing to try to help her."