2001 johnson 90 ocean pro rpm range

[deester]

Can anyone tell me the proper rpm range for my motor. I am going to try out a new prop Friday and I want to be sure it is the correct one. I bought a service manual but it isn't here yet. I am the third owner and don't have the owners manual. Thanks a lot.

 

[ezeke]

Re: 2001 johnson 90 ocean pro rpm range

Prop to run 5800 RPM with your average load. The rev limit on your stock powerpack is 6400 RPM.

 

[deester]

Re: 2001 johnson 90 ocean pro rpm range

EZEKE, Thank you for the help. We tried this motor out with the aluminum prop that was on it and came up with 5500 rpm @ WOT. We will be trying out the new stainless steel prop of the same size and pitch and this information will be a big help.

 

[tashasdaddy]

Re: 2001 johnson 90 ocean pro rpm range

suggest prop forum. before you buy one.

 

[Gary H NC]

Re: 2001 johnson 90 ocean pro rpm range

Going to a SS prop in the same pitch may drop the rpms a bit...
Let us know what it does.
I'm getting ready to order a new prop for mine and would like to see your results...

 

[Dhadley]

Re: 2001 johnson 90 ocean pro rpm range

A ss prop in the same general size may or may not drop the rpms. A lot depends on your hull design and set up and what prop you had and what prop you get. Many times we can go to a good design ss prop which has more lift and swing as much or more pitch.

A typical scenario goes something like - someone is swinging a 17" aluminum prop at 5500. Generally speaking you should go to a 15" ss to get at least 5500, maybe a tad more. But the set up is not the greatest. So we switch to a ss prop with good lift and optimize the set up. We find that the lift now allows us to actually swing a 19 at 5700-5800.

 

[ccckirch]

Re: 2001 johnson 90 ocean pro rpm range

I have the same motor, same year. Stock prop was Aluminum 14 x 17. Maxed out my RPMs were right at 5500. Switched to a stainless 13 1/8 x 17 and my RPMs top out at 5200. So yes, I experienced a drop with a switch to SS. Would like to hear what you decide and the results.

 

[deester]

Re: 2001 johnson 90 ocean pro rpm range

Well, I got the prop and it dropped my rpms down to about 5100 but the speed went up from 37 mph to 42 mph. I am going to start a new thread to find the right size prop as I can only swap this one once. Thanks for all of your input on this. I will also post what the final results are here as i get things finalized.

 

[Dhadley]

Re: 2001 johnson 90 ocean pro rpm range

You probably have the right prop or at least pretty close. We're back to what I was talking about in the other post - set up. We can assume the set up wasn't maxed out for the aluminum prop therefore it's off with the ss prop.

Generally speaking the ss prop should run at a higher X dimension than the aluminum prop. Before swapping props again you might think about maxing out the set up. Raise the motor a little and see what happens, it's basicaly free. Seems like you have a pretty good baseline so improvements will be easy to see.

 

[deester]

Re: 2001 johnson 90 ocean pro rpm range

Dhadley, Can you be a bit more specific about set up. I am new to this and don't know exactly what you mean. Also when you say to raise the motor do you mean to actually lift it up off of the transom or trim it up (which, by the way, I did to get the 42 mph out of it). Before I trimmed it up it would only run about 40 mph and 5000 rpms. Thanks.

 

[Dhadley]

Re: 2001 johnson 90 ocean pro rpm range

Yep, unbolt the motor and move it up. That means less gearcase drag which means more efficiency.