Aluminum prop hits hub on OB but SS prop doesn't.

[larboc]

80's inline 6 90hp "tower of power"

It has a 15" pitch stainless prop on it now. I went to put on a 17" pitch, larger diameter, aluminum prop that I have laying around and the stepped part of the prop's hub hits the gear case. If I had a second thrust washer for a spacer it would fit without hitting. Is this ok to do or is there a thicker thrust washer available?

I think the aluminum prop came off of a mercruiser.

 

[Faztbullet]

Re: Aluminum prop hits hub on OB but SS prop doesn't.

You need the matching washer that fits the alum prop and a Mercruiser prop wont fit a inline unless its a old ,old Renault outdrive....

 

[Chris1956]

Re: Aluminum prop hits hub on OB but SS prop doesn't.

What Fazt is saying is that the Mercruiser prop has a 4-3/4" hub and the inline was designed for a 4-1/4" hub propeller. I put a couple of washers on top of the thrust hub and tried a large hub prop on my inline onetime, but I do not remember if it worked well or not.

 

[Bondo]

Re: Aluminum prop hits hub on OB but SS prop doesn't.

What Fazt is saying is that the Mercruiser prop has a 4-3/4" hub and the inline was designed for a 4-1/4" hub propeller. I put a couple of washers on top of the thrust hub and tried a large hub prop on my inline onetime, but I do not remember if it worked well or not.

Ayuh,.... I remember Both experiments,....

Puttin' a large gear case prop on a mid-sized case, causes prop blow out, from the excess space....

Puttin' a mid-size case prop on an outdrive, causes prop blow out, from the excess space, 'n exhaust gases...

 

[larboc]

Re: Aluminum prop hits hub on OB but SS prop doesn't.

Hmmm, I think I might put some washers between the prop and thrust washer just so I can try out the larger prop to see if it would bring my R's down at cruise a little. The boat snaps hard out of the hole but the engine sounds like it isn't working very hard at cruise, 25mph. It tops out at a little over 35mph and gets there in a hurry. I feel like it could use more prop.
If I like the bigger prop I'll try to find the correct one for my gear case.