WOT RPM for 1988 120 Evinrude?

[rustyscrew]

Sorry, my manual is still on order from Iboats. In the meantime, anyone know what the WOT RPMs should be for a 1988 120hp evinrude?
4500?


I am going out this evening to test out the prop that the engine came with, but I think it has too much pitch.

 

[Windykid]

Re: WOT RPM for 1988 120 Evinrude?

5500-5800

 

[johnson1989]

Re: WOT RPM for 1988 120 Evinrude?

I have a 110HP 89 and it run about 5100 to 5300 at WOT

 

[ezeke]

Re: WOT RPM for 1988 120 Evinrude?

Your motor is a big bore looper with a full throttle operating range of 5,000 to 6,000 RPM. It has a power pack RPM limiter set at 6,700 RPM.

 

[rustyscrew]

Re: WOT RPM for 1988 120 Evinrude?

my manual arrived last night and it looks like WOT is 5000-6000 so I guess I am going to aim for 5800. I got some values of RPM and speed that I was going to post once I plot them. stay tuned.

thanks

 

[noelm]

Re: WOT RPM for 1988 120 Evinrude?

I had a pair of those for a long time (untill 2000 when I replaced them) and they are a very powerfull engine and they LOVE revs so make sure you can get to max RPM and do not be afraid to run it there if you want to.

 

[rustyscrew]

New Prop for 120 hp evinrude

New Prop for 120 hp evinrude

I was running 12.75 x 21 prop to get this plot of RPM vs Speed. It was too choppy to open it up all the way, but it looked like I was close to maxing out on the throttle.


I had a merc 1400 on the boat before which was 115 hp and it worked great with a 13.75 x 15 (top speed 31 knots). Now I have a little more HP and probably a different power curve so I need to guess the best prop for it.

I don't need much past 30 knots as it is rarely calm enough to run that fast and I would like it to idle at about 1-2 knots (salmon trolling speed). Right now it idles at 3 knots.

Any ideas?