82 evinrude broken shear key

[COZMOS]

What would cause shear keys to break.Replaced shear key yesterday,motor ran fine,shifted ok.So today we tried it on the water.Motor started fine but i forgot to put fuel hose from tank to motor and the motor stalled.I put the hose on but couldn`t get it started. when i got home i installed another shear key.Motor started up fine. I guess i idled down to soon and the motor stalled again. Im not sure but i think key is broken again.What gives? Sorry the motor is a 82 50 hp. the manual call for 80-85 ft lbs I went 85. thanks

 

[Daviet]

Re: 82 evinrude broken shear key

If you are talking about the flywheel key, it normally shears because of incorrect flywheel torque.
What is the model# of your motor and maybe someone can tell you the proper torque.

 

[COZMOS]

Re: 82 evinrude broken shear key

Yes it is the flywheel key . I replaced two and they both broke plus the original one also broke. My manual says 80- 85 ft lbs motor model # e5obecnr

 

[Daviet]

Re: 82 evinrude broken shear key

Make sure the crankshaft and flywheel yaper are clean, any thing that will not let the flywheel seat on the crankshaft will not allow you to torque the flywheel properly.
The key is there only to set the timing, the flywheel uses the proper taper fit and torque to hold the flywheel in place.

 

[COZMOS]

Re: 82 evinrude broken shear key

ls it possible for the taper on the flywheel to wear out? Mine looks a bit worn out.Possibly due to slippage.

 

[F_R]

Re: 82 evinrude broken shear key

Things that cause flywheel keys to shear:
1. Improper torque
2. Oil or whatever on the tapers. They must be shiny clean and dry.
3. Previously sheared keys. Every time it shears one, it damages the tapers and keyways. Do it enough times and you might as well junk it.
4. Over torqueing is bad too (read impact wrench). Spreads the flywheel taper. No way to shrink it back down again once the damage is done.

 

[COZMOS]

Re: 82 evinrude broken shear key

Hey FR when you said junk it I hope you mean the flywheel and not the whole motor

 

[tx1961whaler]

Re: 82 evinrude broken shear key

Depends. If the bore is spread from over-torquing, then the flywheel can be replaced. If the keyway is messed up from one too many broken keys, then the crankshaft is toast.... I do know a way to fix it but it requires machine work and you might as well replace the crank and do it correctly.

 

[COZMOS]

Re: 82 evinrude broken shear key

From what you guys have said it looks like my flywheel is toast.The key way on the crank shaft looks ok.Not sure what to look for but the shaft is not scored, the keyway is not spread.As for over torquing i don`t know. J just bought the boat. So who knows.I know i went by the book.Do i have to buy new or can i buy used.

 

[tx1961whaler]

Re: 82 evinrude broken shear key

Does not look to be available new.

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