F115 sounds like engine overspeeds

[Seabags6016]

2015 F115 engine with 65 hours on it wants to over speed when throttle gets pushed above 2900 RPM. Initially I thought it was balance/trim issue. Happened a few times last season (new boater) and went away. Last night, engine sounded rough, but subsided after small trim adjustment. Then, after an hour underway, it really sounded like the prop was slipping, or a transmission in an auto slipping. Every time I pushed throttle up past 2800 RPM a small way 1/2 inch, it shot up to approximately 4500-5000 RPM with no sensation of power or torque.
I've had it winterized, summarized before using it this summer. Fresh gas was put in. Been using Yamaha lube with tankful's.

Any ideas before I pull it out and take it in?

[Seabags6016]

Thanks Scott, I kinda thought that's what it might be. Just wanted to throw it out there in case something weird was happening.
Bags.

[99yam40]

As he said mark it to make sure it is spun.

sucking air could do the same. like too much trim or jack plate,
air or water disturbance

[Seabags6016]

I sure will. I'm thinking of going to an aluminum prop to help save the lower end. My lakes are shallow in many spots. Then get my damaged prop repaired and use for a spare.
Currently, its a 14 in diameter with a 12 pitch. Do I need to do any conversions going from steel to aluminum that you know of?

[panasonic]

I sure will. I'm thinking of going to an aluminum prop to help save the lower end. My lakes are shallow in many spots. Then get my damaged prop repaired and use for a spare.
Currently, its a 14 in diameter with a 12 pitch. Do I need to do any conversions going from steel to aluminum that you know of?

So have you struck your prop in the past in these shallow lake's? If you did strike hard with a stainless steel prop you may have damaged your prop shaft. You may want to have the runout of the shaft checked and make sure the shaft is not bent.

[99yam40]

I sure will. I'm thinking of going to an aluminum prop to help save the lower end. My lakes are shallow in many spots. Then get my damaged prop repaired and use for a spare.
Currently, its a 14 in diameter with a 12 pitch. Do I need to do any conversions going from steel to aluminum that you know of?

I have read you go up in pitch when going from SS to aluminum, I believe it is because of the extra cup SS has

[Seabags6016]

No, just hedging my bets.......lol

[Seabags6016]

Turns out, my dealer said it was too high and lowered it a hole. Will post when Sea-Trialed.