Lower unit from 150 to a175

[notjason]

I am looking at buying a boat with mercury 175 with bad lower unit. Story is water got in gear case and froze. Its a 1994. I found a good 1989 lower unit off of a 150 hp mercury. Will they interchange? Any advice you can think of will be appreciated. I plan on compression testing the motor is their anything else i can do before buying to help protect myself. Thanks in advance. The motor has been sitting for 2 years.

 

[Chris1956]

Re: Lower unit from 150 to a175

If they are both bigfoot gearcases, with a 4-3/4 inch hub diameter, I believe they will interchange fine. If the '89 is a 4-1/4 diameter gearcase, the torgue from the 175HP motor may damage it, but it will bolt up fine. I put a gearcase from a '88 150HPV6 on my '93 135HPV6, w/issue. It eas a bigfoot version.