Prop just touches cavitation plate...

[ktisdall]

I bought a michigan stainless apollo 15.5 x 17 prop from a craigslist seller. The prop is in nearly new condition.   From the Michigan web site info, the prop is SUPPOSED to fit my 1984 Johnson 175.   When installed, the prop just barely misses the cavitation plate.  If I press up on the prop I can make it hit the plate, and I expect the force of pushing the boat will deflect the blades slightly and it will hit.

I could try to resell it or have it resized.  

What is the minimum clearance needed for proper operation?  1/8"?  1/4"?

--Kevin

[dburr]

Look at this...

http://forums.iboats.com/showthread.php?t=347246

Don't know if it is correct, but 1/8" is working with a Rebel on an Etec.  


On inboards clearance like this would vibrate your fillings out.  In a previous life one of my lugnut buddies put a wheel that was to big (less then 5% tip clearance) on a wood lobster boat.  He went like a scared cat but also blew all the caulking out of the garboard and shutter seams right above the wheel....  Lucky the bilge pump worked.  He ended up running her up on the store beach to keep her from sinking.  We pulled the wheel and recaulked when the tide went out. (It runs 11ft up here).

Good luck!

[ktisdall]

That link shows pretty much what mine looks like.  I re-checked the michigan site and they say it fits my engine.  I called H&H prop shop to see if it could be cut down a little. They said no, and also confirmed it is a fit for my engine.   So I'll go try it and see what happens.

Good story about the lobster boat.  A friend had a 31' Beal at one time.  We kept scuba gear and 5200 aboard all the time.   That thing had more 'issues' than any boat I ever saw.  But we went all over creation with it and never had anything major stop us.  Good stories forever after though.

--Kevin

[dburr]

Be interesting to know the results.. The wheel may make make its own clearance if it does just dress 'er up with a chainsaw file  the vent plate will lose!..