Max RPM

[gshldon]

Just wondering if anyone knows of hand what the RPM should be at WOT on a mercruiser 898, chev 305. I had the boat out today and it ran great, but as i was coming in i decided to open it up and at wot my rpm's were 4200-4300, with a speed of 42 mph, i was thinking the motor should be turning more around 4800 rpms. If anyone can answer this question for me i would really appreciate it.

Thanks and Happy boating

 

[QC]

Re: Max RPM

I'm finding 4000 - 4600, see if anybody else responds. How typical was your load?

 

[gshldon]

Re: Max RPM

My load consisted of myself and 2 kids total weight maybe 325 lbs, i am running a 19 pitch prop also. Since i dont normally run at wot, i never really checked it but i just happened to check it today and i think it is just a little low?

 

[QC]

Re: Max RPM

I checked and it appears all of them were rated the same 4000 - 4600. Altitude? Same all the time?

May want to repost in the propeller section. The 898's were rated 198 hp at the flywheel so compared to today's ratings that would be about 170 propshaft. 42 MPH is not that bad for a 170ish 18 foot I/O, so I am thinking you are close and technically in spec if your data is correct.

 

[gshldon]

Re: Max RPM

yeah i am in agreement with you that it is probably close to spec, and everything runs great from take off to the wot and doesnt bogg at all, it was mearly an inquisitive mind of mine, and i just want to make sure everything is running at peak performance.