prop hub

[amphibious]

Hi, i just picked up a evinrude 18 hp fastwin,but i"m not sure what year it is. The only #" on it is 304781 and 381741. The problem is when i put it in gear it works ok in low,but the minute i put it in high it make a high pitch noise and doesnt go fast.I"m thinking it is a spunned hub,but i"m not sure.It has a rubber bushing in prop.Could this be the problem?I put the motor in gear and was able to spin the prop real easy,without the shaft turning.Can someone give some advise as to what might be happening?And how i can remedy the problem. Thanks

 

[ezeke]

Re: prop hub

304781 is the part number of a cylinder bypass cover used on 18, 20, and 25 HP motors and probably others in the 1950s and 1960s.

You could post a picture and someone may be able to identify the motor.

The propeller hub bushing can be replaced by a prop shop or you could purchase a new propeller.

With the propeller removed you may find a stamped part number visible from the rear.

http://boatpropellers.iboats.com/?dz=36857

 

[amphibious]

Re: prop hub

Ezeke, thanks for the info. I"ll try to post a picture tomorrow.Is this the problem a spun hub?

 

[reelfishin]

Re: prop hub

If his motor is from the 50's or 60's, wouldn't it still have a shear pin type prop? I have both a 1957 Johnson and a 1975 Johnson which both still use a shear pin prop.
If he's got a rubber bushing type prop, or through the hub exhaust, it's going to be much later.

A spun shear pin, (behind the prop), will make some strange noises if the engine is revved and the prop slips.

 

[amphibious]

Re: prop hub

hi.there is a shear pin behind the prop ,but it is not sheared .it has the rubber bushing.do you think there could be another problem as to why in high speed it doesnt go fast?

 

[reelfishin]

Re: prop hub

Put the prop on, (remove the plug wires so it won't accidentally start), then try turning the prop with the motor in gear. Does it slip? I would think that that type of bushing would slip even when dry if that far gone.
( I have a few spare props handy here, all have either no bushing or a brass insert). They are for my 1968 18hp and my 1975 25hp motors.

 

[amphibious]

Re: prop hub

I tried that already. It does slip real easy.I took out the brass bushing and the rubber fell apart ,so hopefully that was the problem.Thankyou.

 

[ezeke]

Re: prop hub

The OMC props have the brass center hub with the rubber bushing between it and the outer section. You cannot clearly see the bushing when in place but it is there. The drive pin is stainless steel and should only fail if the bushing fails to give way.

 

[outlaw241]

Re: prop hub

on the model # my 1968 18hp has the #stamped on a freeze plug just behind the fuel pump an i had my hub rebushed also

 

[cc67]

Re: prop hub

If the prop is not all buggerd up I would get it rehubed. I had the one on my 57 FD-11 rehubed for $25 at the prop shop, he did it while I waited. New ones are getting close to a hundred bucks.

 

[samo_ott]

Re: prop hub

Is the model number not on the plate on the transom mount? That's where it should be. If not, post a pic and someone should identify it.

 

[asdasc]

Re: prop hub

Also, if you don't mind sharing, what part of the country are you in and what did you pay for it? I am trying to get a good idea of what these are selling for actually.

Thanks, and I hope the newly rebuilt prop works out well for you!