50 hp Flywheel bolts

[pacertx]

Bought an harmonic balance puller to remove flywheel on a 1988 50 VRO. None of the bolts fit. What size bolts should I use? I read on another post a guy stripped out grade 8 5/16. Is that the size? Are there different threads on grade 8 bolts? 5/16 seems kinda big.

 

[tashasdaddy]

Re: 50 hp Flywheel bolts

ace hardware usually carries grade 8 bolts, it seems that a 50 hp uses 5/16 bolt. smaller motors use a 1/4inch.

PULLING FLYWHEEL

you need a harmonic balancer puller, you need 3 - #8 harden bolts, that fit the 3 holes in your flywheel. standard hardware store bolts will strip out, causing more problems. loosen the flywheel nut, leaving it on so it protects the thread. thread the bolts in 7/16 of an inch. then tighten the puller, adjust so it has a straight pull. now tighten the puller, rap the center bolt with a hammer, then tighten some more. you may have to let it sit over nite, and repeat in the morning. this is a compression fitting, it will eventually POP!!. do not loose the woodruff key that goes in the groove of the flywheel and the crank shaft. then installing the flywheel, it has to be totally clean, no oil, woodruff key in place. then torque the nut to the specifications for your particular motor. if you do not do this, the woodruff key with shear, and you will be repeating these steps.

 

[F_R]

Re: 50 hp Flywheel bolts

Bought an harmonic balance puller to remove flywheel on a 1988 50 VRO. None of the bolts fit. What size bolts should I use? I read on another post a guy stripped out grade 8 5/16. Is that the size? Are there different threads on grade 8 bolts? 5/16 seems kinda big.

Grade 8 refers to the strength of the bolts. Grade 3 are weak, Grade 5 are better, Grade 8 are super strong. You need it because you are going to be putting a heck of a stress on them.

 

[BigB9000]

Re: 50 hp Flywheel bolts

also, its probably 5/16th or 1/4 fine thread.

You can get them at home depot, down the nut and blot isle. In the 'specialty fasteners' drawers, the one labeled standard. grade 8's will look like a gold color, and 5's are the nickle color.

8' i believe cost $0.53 each, and 5's are $0.40 I believe. The depot by my house usually is out of 8's so I sometime get away with using 5's.
Also. I believe I use 3" or long bolts

Also, buy grade 8 washers too. It seems the bolt head likes to force its way into the slots of the puller sometimes. I always put a puller in there

Also, on your puller, there are 2 sides, a flat side, and a curvy side. you'll want the curved side down.

I don't have a spanner wrench to hold down the flywheel, so I just hit it with the impact wrench. Ive never had a hard time getting one off. ever.
...I know that may not be recommended, but that's what I do

 

[tx1961whaler]

Re: 50 hp Flywheel bolts

1/4-20 Grade 8 bolts