Flywheel nut vibrating loose.

[burner217]

Hi, I have a 1973 50hp evinrude and the flywheel nut keeps coming loose no matter what I try.
The previous owner was a shadetree mechanic and I am wondering if it is the right flywheel nut.

I took the nut to a local fastener maker and they said it was a M24 with 1.75mm threads and didnt have one and didnt know where to get one.

This is a metric nut and I would think it should be american.

Can someone please tell me if this is suppose to be an american nut and if so what size it is suppose to be.

I have tried loctite,tapping nut as I tork it to 105 and it still vibrates loose and it makes me think it is the wrong size.

Thanks for any help........Doug

 

[ezeke]

Re: Flywheel nut vibrating loose.

The part is standard OEM and should be purchased from a BRP authorized dealer: http://dealerlocator.evinrude.com/EN/?Rnd=1172157085156

 

[F_R]

Re: Flywheel nut vibrating loose.

The part is standard OEM and should be purchased from a BRP authorized dealer: http://dealerlocator.evinrude.com/EN/?Rnd=1172157085156

It is a special nut and it is inch-threads. Get it from a dealer or http://shop.evinrude.com/ However, if the motor has been running with a loose nut, the flywheel and crankshaft are probably destroyed and will never stay anyway.

 

[kenmyfam]

Re: Flywheel nut vibrating loose.

Get the right nut

 

[burner217]

Re: Flywheel nut vibrating loose.

The flywheel and crank look ok when the key sheared 1 time it doesnt look like it has been scarred.
I was watching it vibrate while idling and would shut it down.
Thanks for the help I have a dealer 2 miles away.
Happy boating.........Doug

 

[Faztbullet]

Re: Flywheel nut vibrating loose.

When you get correct nut and key, remove the sheared one and use fine valve lapping compound to lap flywhel to crankshaft taper. This will ensure the tightest fit and it is in the service manuals on large engines. You can also do a search for lapping here on iboats.