Evinrude 35hp Not getting max rpm

[fbronco86]

Hi,

I have a 1983 evinrude 35hp. Its on 85 17ft alum bass tracker. I purchased this boat not long ago. I took it out on the water and the motor did not sound like it was getting max rpm so I got a tach and found I am getting 4700rpm at WOT. I should be 5200-5900 from my book. Engine compression is 120psi on both cylinders.

Do I have prop issue? It has a 10x13. Or not enough hp? Dirty carb? Boat seems to run pretty well.

 

[goldstem]

Re: Evinrude 35hp Not getting max rpm

probably the prop. that sounds like a lot of pitch for a 35hp to swing on a 17 foot boat. I'm not sure which gear ration the '83 had (it changed a bit in the mid-80s) but if that was the old gear ratio no way you could swing that prop.
for reference, with the old ratio, a 13 foot whaler used the 13" pitch, (primarily)
and with the newer ration swung a 15" pitch. and would get a little over 30mph out of it.for skiing and such we go down to the next prop (either 11 or 13).

 

[fbronco86]

Re: Evinrude 35hp Not getting max rpm

I have not been able to find when they changed the gear ratio? Its either 1.92 or 2.15?

I am kinda thinking the boat has way to much prop on it too. The guy that I got the boat from said he just replaced the prop not long ago. I am sure someone told him he could get more speed with this 10x13 prop.