Fat 50 V-4 Gearcase Question

[jerry-ahrens]

I have a fat 50 Johnson mechanical shift that has a leaky gearcase. Can I use the regular OMC shift rod bushing (remover installer) tools to replace the shift shaft O-ring ? I’ve never been in to one of these, so wondering.. Thanks for your help!

[frankr]

At the risk of being proved wrong, I do believe it has a thicker shift rod (larger bushing). So the answer would be no. However, the 75hp also has a larger bushing and you can get the o-ring out and replaced without removing the bushing. Sorry, just not sure about the 50.

[outbdnut2]

I’d swap the whole lower unit with one from a V4 60 or 75 HP, if you can find one – that is unless you want to stay 100% original. They are smaller/sleeker and you will get better performance and gas mileage. The Fat 50’s lower unit is like dragging a club through the water.
Dave

[jerry-ahrens]

Ok, sounds good. I looked up the bushing and shift rod O-ring…. and your’e right Frank, the bushing is a lot different. I’ll give it a try and see if I can get the O-ring out. Believe it or not, the motor belongs to a customer of mine who has it mounted on an Alumacraft Queen Merrie 18, so I think he will want the original lower unit. Kind of a neat rig. Seems like this year the 50’s motors are coming out of the woodwork… I just finished up a rebuild on a Golden Javelin that had been in storage since the mid 60’s, also on an Alumacraft.

[jeff-register]

Jerry,
the wood has rotted here in Az. 70’s mabey early 80’s they were gone! Enjoy so much, I have a nice 78 85hp O.M.C. too. Broke a few ribs skiing behind it
& wouldn’t change a thing!

[frankr]

The 50hp lower unit actually was re-introduced in the 1960’s as a "Heavy Duty" motor. It’s great for heavy boats that aren’t going to break any speed records no matter what, but not as fast on a light one.

[jerry-ahrens]

Ok, got the gearcase apart. I have a bad driveshaft seal, and a very leaky shift shaft O-ring. FYI, the O-ring is easily removed with a pick tool. Thanks for the help!

[jeff-register]

D-shaft surface & seal?

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