'93 25HP J25RETS maximum sustained RPM

[tucker99]

Engine runs great, 5400 Max RPM. I like to scoot around and the boat runs great at max RPM, but I don't want to blow it up. Practically speaking, how fast can I run this motor for extended periods, say 30-minutes, without screwing-up something?

 

[MrGiggles]

It should be designed to run max RPM indefinitely. Fuel economy will suffer, peak economy is usually reached long before wide open.

Snowmobile engines (which are built very similarly) turn 10k+ routinely.

 

[GYPSY400]

Yup.. run 'er wide open.. that's what the previous owner did

Sent from my SM-G960W using Tapatalk

 

[Pappy]

Guys...it is a piece of mechanical equipment.
Yes, during development the engines were run hard. Harder than customers would normally run them.
Any piece of mechanical equipment, including your outboard, will never see the normal service life it should or can if it is run at maximum all the time. Back off to a good cruise and keep up with maintenance and the engine will last.

 

[nccatfisher]

I have found on just about all of them that you can run them up WOT back them off 15% or close to it and your speed won't decrease hardly any but your fuel consumption will drop 20% or better and your motor will be just as happy as can be.