what rpm should wot be on a 1988 60 Johnson

[atengnr]

Just got this motor last week. Its has a 13 3/4 x 15 prop. Boat is a 15 ft saftmate.

Added a temporary tach yesterday, motor hits about 5700 rpm at WOT. Is this OK? Whats the max this motor should be run at??

 

[ob]

Re: what rpm should wot be on a 1988 60 Johnson

5500-6000 is the recommended wot operating range.Optimal engine height set-up will allow you to get the most from your combtherwise you're current wot rpms are within range.

 

[atengnr]

Re: what rpm should wot be on a 1988 60 Johnson

Is this information stated on the motor somewhere??

So up to 6k is ok for this motor?

 

[andy6374]

Re: what rpm should wot be on a 1988 60 Johnson

Yep

 

[atengnr]

Re: what rpm should wot be on a 1988 60 Johnson

OK, Im confused here. I have found literature that says the 60 hp has a max of 5500 rpm, and others saying 6000 rpm. What gives??

 

[rickdb1boat]

Re: what rpm should wot be on a 1988 60 Johnson

That motor will run fine when propped for 5800-6000 Rpm at wide open throttle with a normal load on the boat. My OMC Manual states that the recommended operating range is 5000-6000 RPMs. Always best to prop toward the top of that range to avoid lugging the motor, which can cause big problems with carbon buildup on the pistons and rings ....I have a 91' 70 HP, which is essentially the same motor and I have it set up to run 6000 wide open. Been like that since new and runs like a top...

 

[atengnr]

Re: what rpm should wot be on a 1988 60 Johnson

From what Ive found, the 70hp has 5k-6k range while the 60hp is 4.5k -5.5k range..Any ideas on what is different about these motors?? Perhaps max HP occurs at a lower engine speed with the 60 vs. the 70?

 

[Dhadley]

Re: what rpm should wot be on a 1988 60 Johnson

Different motors in the same family may be rated at different rpms. There are 60's, 70's and 75's in several configurations.

 

[atengnr]

Re: what rpm should wot be on a 1988 60 Johnson

Thanks for the replies. I called Bombardier and they confirmed that the max operating rpm is 5500 for this motor.

Is it OK to exceed this max rating in light of this engine being similar to 70 hp that has a 6000 rpm max rpm???

 

[Cricket Too]

Re: what rpm should wot be on a 1988 60 Johnson

You will be fine at 5700 RPM, and can even go higher to 6000 if you want. Listen to the experts here, they know more than the guys at Bomby. That engine was made 12 years before Bomby even took over OMC.

 

[rickdb1boat]

Re: what rpm should wot be on a 1988 60 Johnson

Might want to call them back and ask them why the Factory Manual calls for 5000-6000.........

 

[Dhadley]

Re: what rpm should wot be on a 1988 60 Johnson

Keep in mind that motors of the same family (let's say the 56 cid 3 cylinder family) are rated at different rpm's and that rating is certified by the NMMA under strict guidelines. The factory cannot tell a consumer anything different.

 

[atengnr]

Re: what rpm should wot be on a 1988 60 Johnson

Keep in mind that motors of the same family (let's say the 56 cid 3 cylinder family) are rated at different rpm's and that rating is certified by the NMMA under strict guidelines. The factory cannot tell a consumer anything different.

Are you suggesting that perhaps the max HP of a 60 occurs around 5500 rpm and other similar motors - 70 hp have max power at some different rpm say 6000 rpm??

Anyone have dyno charts of a 60 vs a 70 (or similar case where same motor is used but has different HP ratings)??

 

[rickdb1boat]

Re: what rpm should wot be on a 1988 60 Johnson

Yes, they are rated for Max. HP at different RPM's. But I would think that the Factories own Manual would be the best source for WOT recommendations. If you can't rely on that, then what can you rely on...

 

[atengnr]

Re: what rpm should wot be on a 1988 60 Johnson

Yes, they are rated for Max. HP at different RPM's. But I would think that the Factories own Manual would be the best source for WOT recommendations. If you can't rely on that, then what can you rely on...

If possible, I would greatly appreciate it if you would fax this to me..734-523-3942.

 

[atengnr]

Re: what rpm should wot be on a 1988 60 Johnson

What is the displacement of this motor?? When was teh 3 cylinder displacement changed from 40.7 to 56.1??

Thanks.