85 mariner 90hp inline 6

Joined
Apr 24, 2011
Messages
3
Can anyone tell me what the RPM range is for a 1985 Mariner 90hp inline 6. I'm running 4900 rpms and trying to figure out if I should re-prop ???
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: 85 mariner 90hp inline 6

My unconfirmed info says 5,500 rpm If you give us your max rpm and speed and prop size we can better tell if your setup right.Also wouldn't hurt to know how the boat performs,hole shot etc.
 
Joined
Apr 24, 2011
Messages
3
Re: 85 mariner 90hp inline 6

I have a 13.75 x 15p prop. it's a bullet out of the hole and tops out at 34 mph. WOT it is right at 4900 rpms. I am usually at 4500-5500 ft. elevation.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: 85 mariner 90hp inline 6

At 5000ft you lose about 15% of your power Your description sounds pretty good especially if you go to lower elevations.From your description I wonder if your tach might be reading a little
low.See if you can borrow a shop tach to varify your numbers.
 
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