Possible motor swap

SHickey

Petty Officer 1st Class
Joined
Apr 29, 2011
Messages
263
Hello

I am having some problems with my Strarcraft American 20 that is powered by a 74 Mercruiser 165 with a MC-1 outdrive. The motor has a knock originating from the lower rear portion of the motor and I am about 90% convinced that it is a the crank bearing situation. I am thinking about pulling the motor and having it professionally serviced with new bearings. In the mean time, I also have a 76 Mercruiser 140 with a MC-1 outdrive that is in a project boat I am working on.

I was wondering if I could swap the 140 for the 165 (while it is being serviced) and if the 140 could be mated with the transom plate that was designed for the 165. In other words, could I pull the 165 without removing the transom plate and install the 140 and then swap the two outdrives because they probably have different gearing configurations? I am also thinking that if I remove the motor in either boat, that transom plate and outdrive housing can be removed easily so that new outdrive gaskets could be replaced on both boats.

Or is this idea of swapping motors too much work for a very novice mechanic and perhaps I should take my chances and see if I can get another season out of the motor and have it serviced over the winter??

Any advice or experience with swapping out motors would be most helpful.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,230
thats a lot of work to pull out a 6 and put in the 4. not to mention the extra holes for the new motor mount location.

pull the 6 and go thru it. could be the crank bearings, however could also be a cracked flywheel. I wouldnt risk running it myself.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,082
Ayuh,..... If ya swap motors, ya gotta also swap the drives, as the motors use different gear ratios,...
 
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