I have two motors for my new boat, but only need one, so I need to sell the other. But, I don't know which wone to keep. I have an '83 Mercury 25HP long shaft. This motor is very clean, pull start, idols nice, and I feel like it may be more reliable. The only con to this motor is that I will have to buy or make a jack plate. The other motor is a '77 Mercury 25HP short shaft. This motor is a lot dirtier, a little more beat up, but has electric start. It needs the carbs cleaned out a little bit, but runs well. The two good things about this motor is the electric start and that I won't need a jack plate. Neither of them will be able to ve tested on the boat first. Any opinions would be great, I need to get one listed and sold. Thanks in advance.

Christian

I ran a long shaft motor on a short shaft boat for years with out issue. Can you swap the lower units between motors?

I could but it would be kind of a pain, plus the short shaft unit is a little rough.

Oh and thanks for the reply.

I would run it long shaft too unless you run in really shallow water. I have a long shaft on a jon boat and never had an issue. I would try to adapt the electric start to the 77.

I could change over the electric start if I wanted too. But Iddon't really want the extra battery.

I had a long shaft motor and a short shaft boat years ago.  All short shaft transom's were considered unsafe and that is

why boat manufacturers made 20 inch transoms, and got away from 15 inch versions.

I raised my transom up 5 inches to accomodate the long shaft motor and at the same time, made my boat safer.  Short

15 inch transoms were common back in the 50"s

I had a long shaft motor and a short shaft boat years ago.  All short shaft transom's were considered unsafe and that is

why boat manufacturers made 20 inch transoms, and got away from 15 inch versions.

I raised my transom up 5 inches to accomodate the long shaft motor and at the same time, made my boat safer.  Short

15 inch transoms were common back in the 50"s

 

Raising the transom makes a boat safer????

That make as much sense as football bat.

Did you raise the gunnels too?

Plenty of boats still manufactured with 15" transoms

Mine has the shorter transom. Its a 1978 MirroCraft Deep Fisherman.

Wayne - I think you misunderstood what kind of boat he has.  As such, your remark comes off as being pretty snarky. 

run a compression test on both and see what you get.

Compression in both are good. Already checked that.

A hint.  Get on the Mercury web site.  You can enter the serial numbers of the motors and find out what parts are still available for your motors.  Might make a big difference in your choice.