18HP Evidrude Prop?

[steveb1461]

I got an email from a guy on this forum. My motor runs great, rebuilt carb, idles great, runs great, but doesnt get up to RPM? The guy that emailed thought either wrong prop? and/or motor sits too low in the water? It sets so there is about 3-4 inches over the cavitation plate at full throttle. I adjusted the motor pitch so it planes well, but there really is no hole shot, just a gradual up and go. I used to have an old 10 hp johnson around the same era that would scream. I would think this 18hp would push a 14ft. row boat pretty quick. Any ideas?<br />Thanks,<br />Steve

 

[ezeke]

Re: 18HP Evidrude Prop?

What prop do you have now?

 

[steveb1461]

Re: 18HP Evidrude Prop?

My question I guess is, what prop should this motor have on it. And where should it sit in the water on the boat. Is the cavitation plate supposed to show at full throttle? If I raise the motor up, will this make the RPM come up on the nmotor/prop? Really need some help here guys. The model # is 18302L, does that mean it's a long shaft?<br />Thanks,<br />Steve

 

[rickdb1boat]

Re: 18HP Evidrude Prop?

Cavitation plate should be even with the bottom of the hull. Yours sounds a little low and yes, this will affect hole shot and RPM's. "L" should make it a long shaft...

 

[jimmbo]

Re: 18HP Evidrude Prop?

1963. stock prop I believe was 9 1/2 x 11

 

[BF]

Re: 18HP Evidrude Prop?

well dunno about '63, but in 1970, both the 20 & 25 hp OMC's came with 9x10x3 props standard. So I'd guess the 18's would either also have been 10" pitch, or maybe even 9".<br /><br />When I put a 11" pitch on my 25 hp, it gets bogged if there's much load in the boat, so I think at 11" you probably be over propped. I'd bet 9" is where you should be.<br /><br />Take the prop nut off.. the diameter and pitch will be stamped on the backside edge of the prop.<br /><br />Brent