Flywheel nut, 90 hp

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njs458

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The nut uses a 1 3/8 socket but cannot budge it with breaker bar as there is no way to stop shaft rotation. Do I need to use an impact wrench?

Thanks,
Jeff
 
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AlTn

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Re: Flywheel nut, 90 hp

impact will work to remove.... an automotive flywheel wrench will hold it to retorque
 
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F_R

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Re: Flywheel nut, 90 hp

Somebody may challenge this, and righfully so, but sticking a screwdriver between the flywheel gear and the starter works. I haven't bent a starter shaft yet.

A flywheel turner (automotive) or a strap wrench are the proper way to go. You can get it off with an impact wrench, but you need another method to tighten it with a torque wrench (required!!)
 
slag

slag

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Re: Flywheel nut, 90 hp

Here's something else that works. Take a spark plug out and turn the flywheel so that the piston is farthest away from the head/spark plug hole. Then feed a generous length of rope into the cylinder until you can't put any more in there. Slowly turn the flywheel so that the piston compresses against the rope. When its tight, use the breaker bar to remove the flywheel bolt. Once its off, turn the flywheel the other way and then pull the rope out.

The only caveat here is that you need to be careful so that you don't feed the rope into one of the intake or exhaust ports. It all needs to reside in the cylinder.
 
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WernerF

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Re: Flywheel nut, 90 hp

This is a brilliant idea to conserve the piston, but is the stillstanding rod bearing capable to withstand that pressure?
The flywheel torqued to 100 ft lbs may take 200 ft lbs to get loose. In the optimal case crank pin and rod creates a right angle; then on a lever of 1.3 in (half of stroke) there are 1850 pounds on the rod bearing.
 
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Dhadley

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Re: Flywheel nut, 90 hp

You really don't want to turn the flywheel backwards. The screwdriver trick works just fine if you don't have an impact gun.
 
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boobie

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Re: Flywheel nut, 90 hp

Are you sure it's a 1 3/8 "' socket??
 
V153

V153

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Re: Flywheel nut, 90 hp

More like 1 5/16 I think. Fyi a Hayabusa socket'll work too. Dunno how many mm but it fits & my neighbor has one ...
 
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boobie

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Re: Flywheel nut, 90 hp

Slag, I've done the rope trick in a pinch and it works real good. But not to many on here will agree with it but it worked. My only question would be is how many pounds of torque are on the piston, rod and bearings when the cyl fires under heavy load when getting out of the hole at wot??
 
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njs458

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Re: Flywheel nut, 90 hp

You all have my thanks. From Florida, where you can boat all year to Germany, where I do not know your season to boat. Here in central NY I will not get to put the lower unit back on until Spring, I will be ready! I borrowed an electric impact wrench that is as old as this 1985 Evinrude, 90 hp. Spun it off in about 6 seconds. I do think a 1 5/16 socket would have fit better but the 1 3/8 worked fine. I accept all your ideas as possible. As far as putting it back on I have all winter to plan. :)

I had to take the flywheel off and replace it as it was missing 9 teeth, 3 adjoining teeth in 3 different locations. Every so often the starter gear would end up in one of the 3 locations. Have no idea what caused this !! Any thoughts?

Regards,
Jeff
 
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Evenrude1996

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I have a 1996 evenrude 90 hp. Is there a recommended torque pressure for the flywheel? It took 32 ponds for pressure to loosen them.
 
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