Will a 7.5 hp lower unit fit a 6 hp?

[wbeaton]

Quick question. I have a 1968 Mercury 6 hp that needs a lower unit. Will a lower unit from a 1970's 7.5 - 9.8 hp fit or do I need to look for a 60's 6 hp specifically?

 

[steelespike]

Re: Will a 7.5 hp lower unit fit a 6 hp?

A brief look in my after market ser.manual the 2 types are listed in different sections the drive shafts appear different,the shift shaft is angular on the 6,8,9.9 and one piece? and dead straight on the 7.5 9.8.and possibly 2 pieces.Gearcase parts appear different.

 

[wbeaton]

Re: Will a 7.5 hp lower unit fit a 6 hp?

Hi steelespike,

Are you looking at the 1986-89 6 hp, perhaps? The shift shaft on my 6 hp (1961-68) appears straight and is two pieces. Of course, its completely apart in a box so I could be wrong.

Thanks.