Need opinion on repairing a flywheel

[Eddie Rivera]

Need opinions and help on how to or whether I should repair a flywheel with a scratched bore. Please see attached pictures. Can I take it to a machine shop? I know I must have 80% contact from flywheel and shaft, can I use JB Weld to fill the scratches? Or make it straight and tight on the jetway? can I put some welding on it and just file afterwards?

It's my 1989 force 50 HP power head that I'm replacing with a 1991 power head. I had previously installed my flywheel key the wrong way and I damaged the key then I replaced the key and I found the new key with more damage, the motor was only on no more than five to ten minutes total but cranked many times.

I'll include a picture of the shaft the could have also contributed to the damage. I was beer able to leave the key on the shaft I would hold it in place with some anti seize cream. But the new power head has a clean shaft and key is held stuck in place. Much different.

Please advice!!!

 

[Jiggz]

Re: Need opinion on repairing a flywheel

Bring the flywheel to the machine shop and I'm quite sure they can fix it at the right price. But they will also need the shaft to make sure they machine it properly. With the groove so deep, the only fix I can see is to weld build the inside and machine it to fit the shaft and re-create the key way with a milling machine or broaching. Get a price quote and compare it to a price for a used flywheel off ebay or some boat yard. That is the only option I see to properly fix the problem, rebuild the damage one or get a used one with undamaged keyway.

 

[MickLovin]

Re: Need opinion on repairing a flywheel

By the looks of it that shaft will be ok, but the flywheel looks shot, probably be cheaper to find a new flywheel from the wreckers?
Have you priced a new one?

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

Thank you guys. I have been looking around and new it's over $500 used I found one for $120, I still have other places to check and call I just can't find my list if places. I was trying to save by doing something my self or for the right price ask a machine shop to help me. I have taken out my old power head and want to put everything back the right way. The flywheel will be the last thing I install so I am taking my time to shop around and get ideas from you guys.
I still don't know how I'm going to set the throttle tower and how the timing will be affected I need to clean the new/used power head properly and prepare for installation and I got new gaskets for certain things like fuel pump and thermostat and want to make sure I lube cilynders right to avoid damage and when an how to properly start the new power head. It suddenly seems overwhelming so I'm taking my time in first cleaning everything and studying my every move.
Any advice is always welcomed (needed)

 

[Frank Acampora]

Re: Need opinion on repairing a flywheel

REPLACE the flywheel. I don't see it on your engine but most crankshafts have a "land" on them. If the flywheel bore is machined oversized, the flywheel will hit the land and it will never tighten adequately on the taper. It will constantly break keys.

From the photos, I can not tell the extent of the damage.

Factory procedure for re-seating a flywheel is: Coat the flywheel bore and crankshaft nose with lapping compound. install the flywheel WITHOUT a key and rock it multiple times through about 90 degrees. Rotate about 90 degrees and repeat. Do this all the way around then check for mating.

Clean both pieces and scribe multiple vertical pencil lines on the crankshaft nose. Install the flywheel and rotate it a few times. More than 85 % of the pencil lines should be rubbed off.

If not 85 or more, repeat the lapping. AGAIN: If you lap too much, the flywheel will be no good and must be replaced.

 

[wickware]

Re: Need opinion on repairing a flywheel

Please post a pic of the crankshaft. I feel it has to have some damage from looking at the flywheel.

 

[gregmsr]

Re: Need opinion on repairing a flywheel

I have found entire motors for 200-250$. Replace the flywheel would be my advice.......

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

Thank you guys. Per your request I am posting pictures of the shaft and flywheel.
Since I bought this boat the flywheel key would not stay on unless I added some pasty product to hold in place so I used anti seize cream and then installed the F/W.
My second issue was that I installed the key the wrong way the last time and found more damage.
Then I worked in why the moor would not start so I cranked it many times and was in for about 5 minutes total the. I removed the F/W and found more damage. My take is that the shaft was not tight enough and the F/W now is also more damaged cuz I installed a new key and installed it right with nothing to hold it even though I could see it was a bit sideways it was on. When I did lap it I may have done it too much or too many times. I think I did it like 3 times before re installing.
Now it's off and I see kite damage - so please see the pictures and I do think I should just replace it. Do you guys think $120 it's an ok price? The seller assures me it's in fine condition and he has many more like it.

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

This is how I found it after lapping and installing the new key the right way and compare the damage.

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

This is the original state I found it in after I discovered I installed the key wrong and the second picture is after I lapped it like 3 times.

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

Is $120 including shipping ok? Or as one of you guys said that you have found an entire motor for upto 250 meaning $120 it's expensive and I should keep searching for either cheaper part or another entire engine for parts?

 

[pnwboat]

Re: Need opinion on repairing a flywheel

I wouldn't pay $120 for a flywheel. Unless you're desperate, wait for a cheaper one. If I come across one, I'll let you know.

 

[MickLovin]

Re: Need opinion on repairing a flywheel

Just putting it out there but is there any other motor hp besides yours that the flywheel will fit, so your not restricted to the same motor, but preferably if you bought one it would be same.

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

Good question! Does anyone know the answer? I will use it on a force 1991 50 hp power head that I bought it's a model 508F91C.

 

[MickLovin]

Re: Need opinion on repairing a flywheel

Have a look at the parts catalog for hp that is around your size and cylinder, but be careful as I do think there might be a difference if you use one thats too high or low from your size motor, for e.g the flywheel on my 6hp is lighter than the one one the 12.9hp and I wouldn't swap either but if I had a 10 hp or 15 I would swap to my 12.9 as they use similar parts, but someone on here may know a bit more

 

[pnwboat]

Re: Need opinion on repairing a flywheel

Unfortunately he may be somewhat limited limited because it a 50HP 2 cylinder Prestolite ignition system. That flywheel and ignition system wasn't used for very many years.

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel

Ok guys I found me a whole motor, it has the flywheel and for the first time I could see how they are originally set up, meaning I was missing the spacers holding the bracket that holds the ign. Module and the coil packs and thus pinching my wires or putting them too tight against the holding bracket holding screws into the power head. These wires are also nicely protected with see through/ clear plastic and so well protected to avoid contact with the flywheel it's amazing all I'm learning by just looking at it.
Now it's too late but I had to travel almost 5 hours total to buy the motor.
Now I will need advice on how to properly install the new head onto my old motor.
On the bolts I installed from the exhaust plate to the power head I used a lot of anti seize cream on them to prevent corrosion or them getting stuck, how ever when I loosened the bolts I wish they would have been tighter. Do you guys recommend I clean them out and use nothing or leave as it is with all that anti seize cream and just torque properly???????

 

[Frank Acampora]

Re: Need opinion on repairing a flywheel

If you intend to keep the engine for a long while, then use anti-seize. Some say that in salt water use never seize becomes ever seize. You can try Vaseline petroleum jelly--I know a couple of fellows that swear by that. You can also try silicone RTV. I have seen it on water pumps and it does well keeping everything sealed and corrosion free. It is also relatively high temp resistant so should do well on the exhaust cover.

Since removing the engine block can be difficult, it would be better If at all possible, to use the newer engine on the boat and swap other parts--the lower unit, transom clamps, etc.

Generally there are the visible mounting bolts and a hidden one under the water outlet (depending upon engine) Then the two rubber shock mounts need the nuts removed and they may break. At the front there is a rubber motor mount which you can not get to until the choke and carb are removed. Finally, many of the engine blocks are practically welded to the leg by the factory glued gasket and take a lot of fuss to break free--not a pleasant job.

 

[Eddie Rivera]

Re: Need opinion on repairing a flywheel



Good morning everyone! Welcome back!!
These are some pictures of my new motor. This is will be called - motor #3 San Diego for parts only, Motor #2 will be Minnesota the good 4% leak down test power head, and motor #1 will be my original, with 90 Lbs of compression, 1 bad sparkie thread, not staying on with possibly 1 sparkie not firing, 2 screws not so tight on cylinder head cover, possible bad head gasket. For identifying purposes and installation purposes and instructions from you guys.