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I have 3 Mc 49 motors. The clutch side of the crank on one of them has lefthand threads and no keyway. The other 2 have righthand threads and a keyway.
Anyone know why this is? What is the difference?
Thanks for any info.
Wally

Wally,

The 49C had a keyway and the late 49E engines had the left hand threads and no keyway. Both will work just fine in either engine but make sure you have the right clutch nut for whatever one you use. The new Max-Torque clutch works great and you can get either nut or both if you tell Jim Donavan what you want.

Dick Teal

Thanks. I should have know that since I owned several 49C & E motors back in the 70s. Guess it's been so long I just forgot. Senior moment I guess. Seems I have a lot of them now.
I ordered a clutch from Jim today with both left & right hand nuts, so I've got it covered.
Thanks again,
Wally

Wally, I hope you told Jim your exact useage, if you're buying the latest unit. I love my Max Torque, but it's set up with 9 of the brown (maybe they're orange) springs. This puts engagement at 6000 RPM+. That may be a little high for a Mac 49 for fun running. I'd ask him to set it up for around 4500 RPM. Believe me, unless you build one of Jim's shoe/spring installation tools, you dont wanna mess with the beast at home! I watched Jim's demo at Fremont, and with the tool, no problem - but without..... . Anyhow, you'll love the clutch, and the installation instruction sheet is great. TJ

Yeah, Jim and I discussed what the clutch was to be used on. I'm leaving it up to him to set it properly. He did mention the 4000 or 4500 set up.
I have tried to mess with those springs before and I have no intention of trying THAT again.
Wally

Smart guy! TJ