1972 johnson shearing a flywheel key

[changetires]

sheared a flywheel key on 1972 Johnson 40 hp. Is there anything special you have to do with the timing or top dead center when reinstalling the flywheel and key?

tks

 

[jbjennings]

Re: 1972 johnson shearing a flywheel key

THe flywheel key is what takes care of the timing, so nothing special needs to be done with TDC or otherwise. Clean your crank taper of all all grease and oil, install the key and flywheel, and most importantly----torque it to specs. If you don't use an OEM key and don't torque it properly, it will reshear and eventually ruin the crank.
JBJ

 

[wilde1j]

Re: 1972 johnson shearing a flywheel key

No, but the flywheel bore and crank end must be clean and dry, plus the nut MUST be torqued to the correct value. You only get a few tries, before the flywheel and crank become junk. The reason for shearing is almost always the nut wasn't torqued. BTW, don't use a hardware store key.

 

[Faztbullet]

Re: 1972 johnson shearing a flywheel key

Do all the above but I go a step further and lap the crank to flywheel.....

 

[wilde1j]

Re: 1972 johnson shearing a flywheel key

Lapping is fine, if you have enough metal left.

 

[fishfeatures]

Re: 1972 johnson shearing a flywheel key

ok..... I'll ask.....

What is lapping ?????

 

[F_R]

Re: 1972 johnson shearing a flywheel key

A person that should know, says that the 40hp flywheel should not be lapped. He grew up in the Evinrude factory.

 

[tx1961whaler]

Re: 1972 johnson shearing a flywheel key

Torque it to 105 ft-lbs, or it will shear again.....

 

[JDusza]

Re: 1972 johnson shearing a flywheel key

Lapping is an operation in which two surfaces are rubbed together with an abrasive between them, by hand movement or by way of a machine.
J

 

[changetires]

Re: 1972 johnson shearing a flywheel key

Thanks for the reply and answers. I have new BRP keys ordered and will be here shortly. Thanks again for all the info.

 

[1946Zephyr]

Re: 1972 johnson shearing a flywheel key

Yep, those are the shorter keys, since the points cam is molded into the crank. The old ones (1961 and earlier) had the longer key.

 

[Dankeeton]

Re: 1972 johnson shearing a flywheel key

I have a 1958 35 hp evinrude. Anyone know where I can order the correct key (longer one)?

 

[Daviet]

Re: 1972 johnson shearing a flywheel key

Dankeeton, you should start your own post so that you don't get lost mixed in with someone elses.
I think the part number for your crankshaft key is 302602, check with your local dealer, they might have them in stock. Or you can order on-line, but the freight will far exceed the price of the part.