Do I have small gearcase or large gear case?

[atlapp]

I am fixing to order a new prop from Solas on iboats, spoke with a Solas rep last week and he recommended and 11 pitch 14 diam prop...got to looking at my prop today its a 13.25 diam and there is less than 1/2 inch between blade and cavaition plate...so how will a 14 inch diam fit? I have a 70hp 1978 johnson but i think i may have smaller gearcase, how do i tell?

 

[Bob_VT]

Re: Do I have small gearcase or large gear case?

You have the small gearcase.

 

[Texasmark]

Re: Do I have small gearcase or large gear case?

If a Merc, the gearbox dia is 4.25 for small and 4.50 for large. The small comes on mid hp engines up to the 135/150/175 and up V engines where they use the larger. I have a 90 hp and I have run a 14" prop without an interference problem with the anti-vent plate or the trim tab. I did have a length problem I had to fix to keep the larger dia hub on the prop from rubbing on my gearbox housing.

If you are using a 11P on a 75 to 125 hp mid hp engine, you must be pushing one heck of a boat....toon maybe?

Mark