Remove MR1 Drive Coupling

[Robb235]

Need help figuring out how to remove the drive coupling from the 160hp MR1 HO. I have the flywheel held in place, and have torched the drive coupler to heat it up. When looking at the motor from the rear, I’m trying to turn the drive coupling counter-clockwise, since I know it’s not reverse threads. I can get it to budge. Tried hammering on the end of my breaker bar, still no luck.

Any ideas?

 

[WREKS]

Before you do, it would be a good time to check the coupling clearance. If the drive shaft and intermediate shaft are not aligned properly, you may need to add or remove shims. Why are you removing it?

 

[Robb235]

I have a pair of these motors that I’m retrofitting into an XR1800 jetboat. The XR drive couplers are shorter than the MR1 ones. I’m limited in front-to-back engine space, so the shorter drive coupler is important.

 

[WREKS]

Does this help at all? This is for a SX230HO. Left hand threaded, right?

 

[Robb235]

Does this help at all? This is for a SX230HO.

Unfortunately, not really. I have the service manual and read that section.

I don’t think it’s possible for it to be reverse (left hand) threads. When looking at the motor from the rear, the drive coupling spins CCW when running. This means the resistance of the impeller in the water is applying a force in the CW direction. Therefore CW on the drive coupling tightens it, CCW on the coupling loosens it. Plus, the threads on the XR drive coupling were standard (not reverse) threads. I learned the hard way on the motor 2-stroke GP1200R/XR1800 motor because I went into it thinking it was reverse threads. It wasn’t.

 

[WREKS]

Your absolutely right. Impact wrench?

 

[Robb235]

Your absolutely right. Impact wrench?

That will be next. I don’t own one, so I’ll see if I can borrow one this weekend.