Prop tightness issue

[tjello327]

Hi guys,
I have a 1986 125hp Force. My prop is not being drawn up tight with the locknut & washer. It has about 1/16" of movement on the splines. Should it be drawn up tight? The splines stick out past the plastic hub that goes on after the prop about 1/16". I can make a washer to correct this but I am not sure if it is needed. 1/16" seems like too much. I can see about 1/64" or less because I dont think you want to put too much pressure on the plastic hub or it will crack.
Any ideas?

 

[Frank Acampora]

Re: Prop tightness issue

The plastic flare washer should be thick enough to remove any play in the prop. You should have no movement on the splines at all.

First check to be sure you have the correct thrust washer; Mercury and OMC thrust washers will fit, but incorrectly space the prop.

Second check the plastic flare washer for thickness. bearing down too tight on the prop nut will damage the plastic flare washer.

Third, Is the prop the correct one for your engine? Hub lengths vary with applications and some incorrect aftermarket props will fit since the splines on some OMC and Merc engines are the same number and diameter as Force.

Ultimately, if everything checks out OK, then just bear with it and make another washer to fit behind the black plastic flare washer.

 

[tjello327]

Re: Prop tightness issue

My flare washer is off of an unknown engine. Bought off of e-bay and was listed as being removed from the same engine as mine. The prop as far as I know is the correct one but could not be. I am getting ready to buy a new one and will check dimentions against the old one. I guess from what Frank is saying is that as long as the prop is tightend up but not enough to damage the flare washer, then I should be o.k.

Thanks again Frank!

 

[tjello327]

Re: Prop tightness issue

Well I got digging a little more into finding out what is causing this issue and I think I found it. The very first steel spacer that goes on before the prop shows alot of were inside the center hole where there was a 45 degree x 1/8" chamfer. This chamfer is gone which is letting this spacer go too far onto the prop shaft. I do have a spare spacer that still has this chamfer on it and the part numbers do match to original o.e.m. part. When I use this good spacer, the prop & the plastic flare are now sticking out further the the prop shaft splines by about 1/8", this is now letting the flat washer and locknut draw up the prop tight. My question is does this sound right? I now have to be careful not to overtighten the nut. Also is it a good idea to use locktight on the locknut and buy a new locknut? I lost a brand new prop last year due to something not being quite right.

Thanks,
Tom