S/G pulley loose on crankshaft of 149

[Dave R]

I have been using the 149 about a year after an overhaul. I had noticed recently a knocking/rattling sound from the front of the engine. After looking it over and tugging on this and that, it turns out the big pulley on the crankshaft that turns the starter generator was loose on the end of the crankshaft.

I tightened the pulley with the two allen screws. I finally took the pto clutch off and got into it. I turned the allen screws as tight as I could without breaking the wrench, put the pto clutch back on, ran it a while and darn if the big pulley wasn't loose enough to wiggle it again.

I remember when I had it all apart there was a locking collar somewhere behind the big bearing the pto mounts on. Is it possible that collar is loose that is causing my problem. I'm not anxious to take all that off again, but I think that is what's coming.

Dave in SW Missouri

[DoubleO7]

The locking collar for the bearing needs to be locked on the bearing. Otherwise the inner race of the bearing could spin. And the pto could come off the shaft.

You might want to take the s/g pulley off and use a new key and new set screws.

[Dave R]

I thought the locking collar locked the bearing in place, but couldn't remember, the Tech manual wasn't too clear about the big pulley. When spring returns I will take that all back off and see what happened. (Spit snow here today) It had side play which puzzled me. It may have damaged the key. We'll see.

Thanks for the reply Double07.
Dave

[Yosemite Sam]

You do need to keep that large pulley tight, if it gets loose and is run that way, it will wear the bore in the pulley and wreck the grove in the crank shaft... That's a problem you DON'T want to have to deal with.

As Double07 suggested you may want a new key and set screws in it, it's cheap insurance.

Good Luck.

[stihlhawgin]

I have the exact same thing going on with one of my 149s and I'm not sure what to do . Been told I could carefully weld the key way on both and then file back square , but I haven't got up the nerve to try it. Its too bad because that motor runs so good it kills me not to use it . I hope someone has some more suggestions cause I'm afraid welding crank could hurt something inside

[J-Mech]

Originally Posted by stihlhawgin

I have the exact same thing going on with one of my 149s and I'm not sure what to do . Been told I could carefully weld the key way on both and then file back square , but I haven't got up the nerve to try it. Its too bad because that motor runs so good it kills me not to use it . I hope someone has some more suggestions cause I'm afraid welding crank could hurt something inside

DO NOT weld on the crankshaft. It's a simple repair. Just take it off and fix it right.

A worn key will make the pulley "work" back and forth. New set screws should have little "teeth" that bit into the metal they are pressed up against. That helps them stay tight.

[stihlhawgin]

Ok, no welding. So just try new set screws then. Will do. Hope it works ,shaft key way pretty wallered

Thank you for your help

[Sam Mac]

Originally Posted by stihlhawgin

Ok, no welding. So just try new set screws then. Will do. Hope it works ,shaft key way pretty wallered

Thank you for your help

Let's see some pics of the shaft.

[stihlhawgin]

I will try to pull clutch and get some pics tomorrow

[sawdustdad]

If the shaft keyway is badly damaged, isn't a weld repair OK? i.e., add some weld metal to the shaft and re-cut the keyway. I don't see any other way (other than replace the crankshaft) to do a proper repair if the keyway is badly damaged.