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Broken Crankshaft 1991 115hp 4cyl newbie trying to rebuild

jpursley

New member
"Hey,

Please excuse my anno


"Hey,

Please excuse my annoying questions, but this is my first time dealing with a 2 stroke outboard, and I feel lost. I have several questions about parts and crankshaft replacement proceedures. The serial number of the outboard is 0D027999

A friend will be joining me tonight to start a tear down of the motor, and we hope to finalize the list of parts we need to reassemble, and see if there is any damage to other parts we are unaware of.

First question: The Flywheel needs to be replaced. The magnets on the underside are shattered. What flywheels are interchangeable? I see 1996 115hp, 1995 90hp flywheels on Ebay...can I use them?

Second Q: What issues should I be aware of purchasing a used crankshaft?

Third q: What parts SHOULD I replace during this crankshaft installation, and what parts MUST I replace?

I will undoubtedly have tons more questions as this project proceeds. Should I just continue this discussion with any new questions, or do I post a new discussion?

I appreciate any guidance possible. If money allowed, I would just let a pro handle this, but I am basically broke with a broke motor....gotta learn sometime, may as well be now!"
 
"First off, do you have a manu

"First off, do you have a manual? If not, it's worth the 30 bucks...

Looking through the parts lists, the only two flywheels that are listed for your motor are Merc number 261-859236T12 and 261-9008A9.

They were used on 100/115 horse 4 cyl's between 1986 and 1991. If anything else will fit/work, it certainly isn't indicated.

You state that the magnets are shattered - that may well have taken out your stator and trigger under the flywheel as well - so they will have to be tested at the very least.

What happened to the old crank? that will determine some of the other issues you will have to address. You may have "toasted" the gears in the lower unit and the prop shaft.

If something came a complete dead stop sufficient to destroy your flywheel, your connecting rods/pistons may have been damaged as well.

Something to consider as you investigate all the issues and start pricing parts, even in the used market:

A motor of this hp/vintage can be easily obtained in the used market for between a 1000 - 1500 bucks. And that's one in fully operational condition.

You do have the right idea though, to have this work done at a shop would be extremely cost prohibitive - and replacement would definately be cheaper.."
 
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