9.9 Evinrude Crank Case Reseal

[catalyst-519]

Hey Guys.

Ripped the head apart on my 76' 9.9 due to a bad gel seal. But now when I've dry fit the two halves of the case together they dont sit exactly flush. When one side is flush the other side raises up about .5 mm

The centre bearing and connecting rod bearings are lined up and positioned in ine with the locating pins.

I'm thinking this means either a slightly bent crank or warped crank case half. Any other ideas that could be interfering with the seating of this half?

If I use a healthy amount of seal and slowly torque it back down will this slight warping matter? (supposing that's the issue).

Thanks

 

[bktheking]

Re: 9.9 Evinrude Crank Case Reseal

Put the halves on glass and check to see what is warped, could very well be the crank as well. I suspect that was the issue all along.

 

[catalyst-519]

Re: 9.9 Evinrude Crank Case Reseal

Good idea, and if that is the issue, it's an anchor or an money pit right?

 

[bktheking]

Re: 9.9 Evinrude Crank Case Reseal

Depends , I have parts.

 

[jmendoza]

Re: 9.9 Evinrude Crank Case Reseal

I had this exact problem, so check to see if this is what is happening: Look closely at the case sealing surface where the taper pin goes in; look for a slight burr on the edges of the hole the taper pin is in, and the hole it is driven into on the mating case. If you see a slight burr, use a single edge razor blade to shave it off.

The next part is a bit tricky, but a little care is all that is required. You will have to remove the rod caps and bearings and mark them all so they go back the same way, I used a paint pen. Buy new rod bolts, just to be safe. Now you can lap the case halves: Get a dead flat surface, like thick glass or a surface plate and tape down a sheet of 360 grit wet/dry to it. Lube the case with WD-40 and lap it on the wet/dry paper using an figure eight pattern, rotate the case 90 degrees after a few lapping passes, and note where the case is contacting the wet/dry paper. Wipe the case surface frequently to see how the lapping is proceeding. Repeat until it has an even finish, and then do the other case half. Try to take off as little as possible, just the high spots.

You can use OMC Gel Seal, or got to the motorcycle shop and buy some Yamabond to re-seal the cases.

What happens is if somebody drove in the tapered dowel pin too hard, it expands the aluminum around the holes in the cases and makes them seperate...weird, but true, it happened to me. I noticed mine was bubbling oil out the case halfs when running.

BTW: This is a good time to replace the upper crank seal, and the crankcase head seal at the bottom, just to be safe as long as you have it this far apart.