Crankcase compatability for '88/'89 pro50

[beejster]

I am wondering if the crankcase assembly 6H4-15100-10-94 from the '88 Pro50LG is compatible with the still offered 6H4-15100-11-94 from the '89 Pro50LF. They look identicle and I still have all the equipment that will bolt on to the block.

These older units are getting a little harder to keep running, but I am hoping that this will work. If there is a difference between the two, please let me know what it is and if I can make this work.

[mphelle8vld]

I have a running 88 and a 89 parts motor in my garage. This is the year yamaha swapped the locations of the starter and cdi, a quick look shows that some of the mounting bosses have been changed in the new casting. Post photos of your block stripped down or send me a PM.

[beejster]

Thank you for the reply

Everything is at my cabin right now so I can't provide the pictures right now, but I have all the parts for the '88, so they should function together no problem. The only issue will be mounting/attaching to the block. Looking at the diagrams at boats.net, I can't see a difference.

I will be mounting all the '88 parts on to a fully rebuilt '89 block/crankcase assembly.

I am also new to this, so maybe you can help me with the lingo. You use the term 'mounting bosses' and mention a PM? I am not sure what these are.

[mphelle8vld]

A boss is a raised area cast into the block that allows space for a drilled and tapped hole where your components are bolted to, like where the bolts that hold your starter on are screwed into. The sketches on Boats.net are great for ordering parts but you will need clear photos and measurements to know if your parts will simply swap over. A quick look at the two blocks shows that even if possible, it won't be easy. A PM is a private message you can send to any member by clicking on their username.

[beejster]

It is all together now, just need a test run.

Hello again and thanks for your input. Sorry for the delay in my response.

I have put it all together and used washers to shim the starter so it mates better with the flywheel. Seems to engage properly. Another difference was the carbs and the type of choke system, but I believe that my '88 equipment will work just fine. The electronics were bolted on to the block, but not necessarily to design, but they are secure and should still function in the current configuration.

It is just about warm enough here to try a test on the unit, so I am keeping my fingers crossed.