Boat motor RPM

Saltwater Inshore Discussion
1

Hello.

Last time I was out on the water, it was a cooler than usual morning. When I got up and running, I noticed my rpm were sky high than what they should be. Anyone else have an experience like this? Can cooler weather / water, cause this? Or do I need to be more concerned about a spun hub?

Thanks,

SC

2

Cold air is better for combustion, so it should make your motor feel a bit more peppy, but RPM shouldn’t change much due to weather.

What kind of motor and what kind of RPM’s were you seeing versus what you normally see?

Wadmalaw native
16’ Bentz-Craft Flats Boat

3

Hello. Thanks for the reply. Its a Mercury Optimax 90. Seeing 6000+ rpms at 20 mph, compare to 6000 rpm at 42 mph

4
quote:
Originally posted by sacclark

Hello. Thanks for the reply. Its a Mercury Optimax 90. Seeing 6000+ rpms at 20 mph, compare to 6000 rpm at 42 mph

That is way out of range. You should have that checked out. Could be something simple like a bad gauge, but I wouldn’t chance it.

One Simple Thanks!!

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5

that definitely sounds like a spun hub

6

Thanks for the ■■■■■■■■ Gents. I was very borderline on needing a new prop anyway. I think at this point Ill put a new one on, and see if its a fix. I have a very rare 5 days off this week. I would hate to put the boat in the shop, if I dont need too!!

7

if youre in the columbia area, dont take it to a shop, just swing it by my house. at the very least ill be able to tell you what the problem is.

8
quote:
Originally posted by sacclark

Hello. Thanks for the reply. Its a Mercury Optimax 90. Seeing 6000+ rpms at 20 mph, compare to 6000 rpm at 42 mph

Does engine sound like it is actually turning that high? If so Sounds like hub slippage It will show up more so in cold water. On the hill put the engine in gear(not running!) and put your foot on it and see if you can turn the prop without turning the engine over. Skips prop shop off cross county road can press the old one out and install a new one pretty reasonable if that’s the problem.

“If Bruce Jenner can keep his wiener and be called a woman, I can keep my firearms and be considered disarmed.”

9

I’d bet on a spun prop…:frowning_face::frowning_face:

George McDonald ; MAD Charleston
[http://www.militaryappreciationday.org

When you see “Old Glory” waving in the breeze, know that it is the dying breaths of our fallen hero’s that makes it wave.
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