150GT Prop question.

[James R]

I have just now had the SS prop re hubbed thinking that the thing had spun. The symptom was such. The prop turns out to be a Mercury prop. No biggie. However the old hub took a lot of pressure to remove and there was no real strong evidence the it had let go.
An informative comment was made about the possibility of the clearance between the prop outer diameter and the inner of the lower unit being too great allowing exhaust gasses to pass creating a cavitation effect. I am not in a position to measure the bore of the lower unit just now but I will. This prop came with the motor so the PO would have had a problem. The prop looks in new condition.Does anyone have knowledge of this possibility?

 

[Chris1956]

Re: 150GT Prop question.

James, The V6 motors from Merc and Johnnyrude share the same hub props, which is 4-3/4". There are smaller hub Merc props which are 4-1/4". You should see a 1/4" gap around the smaller hub prop, when it is installed.

There are supposed to be filler rings that you can use, but I do not have a url for one.

 

[James R]

Re: 150GT Prop question.

Thanks Chris1956. If there had been such a gap I would have noticed it. The guy is coming over in the morning so I will be able to ut a caliper on the lower and see just what the clearance is.
Your help is most appreciated.

 

[James R]

Re: 150GT Prop question.

The prop was the correct size. The only problem was that the hub replacement was a mercury hub. Very nice but the spline length does not fit the Johnson shaft. The owner was very pleased with the performance of the new Solas aluminum prop I loaned him so we did a trade. I now have a very nice stainless mercury prop on the shelf. It was the hub that failed.

 

[Chris1956]

Re: 150GT Prop question.

You can adapt that Merc prop to fit the Johnny. You need to drill out some of the splines, and see if the thrust hub will fit. You may also need to fashion a spacer under the prop nut, to make the nut tight. I have done it, so I know it will work.

 

[James R]

Re: 150GT Prop question.

Thanks Chris1956. When I spoke to the guy that did the hub he told me that.