Pontoon Boat & Deck Boat Forum

I have a 2014 Crest, Crest 2, 21 foot pontoon boat with a Mercury Power Thrust 115HP. We just upgraded to this motor this Spring. Usually full speed is at about 5400-5500 RPM. It seems like when I first start out and get up to full speed it will be at this RPM then it will jump up to about 6100 RPM. I lower the speed right away but I don't know why it is doing this. After cruising for awhile. Full speed will alwayS stay at 5500PM. Is it just a warm up thing? I am a little concerned since it is a new motor and don't know if this is normal since it seems like it wouldn't be.
ANYONE? ANYONE? BUELLER?

Have you checked for a spun hub? Real easy to do and MAY explain why the RPM's are jumping up. Is the prop venting? Trim help? Could be several things, but my gut is spun hub.
Check it our and let us know!
Sami

5500 rpm's is a little low for that engine. You might need a little less pitch to get the revs to 6000 rpm's. I agree it may be a prop issue.

Thanks for the help. I'm bringing it to the marina on sat. for the guy to take a look at it. I will keep you informed.

Hi guys, chalk it up to an inexperienced boater. Lake Koshkonong in Wisconsin is very shallow so when you pull out from your doc you have to have the motor trimmed up and most likely what it was was the motor wasn't all the way trimmed down so when I would accelerate it would cause the higher rpm's occasionally. That is why I thought it had to do with the motor not being warmed up because it really only happened right when I started out. I pulled out yesterday made sure the motor was trimmed all the way down and took it for 30 minute boat ride accelerating full speed 20 or 30 times and never did. Most likely that was the cause. Thanks for your help..

Glad you got it figured out. I just bought a Crest II this spring with the same motor and I love it so far. Great Boat!!