Maybe a good test for one of the drive guardians?

In the forward engine when your running scx drives ,the shaft you are talking in the week link , l had two of them go, they where twisted ,check the pilot bushing in the end of the crank, Brian forehand says they go all the time when running scx on a high horpower motor.

I didn't even know what a Drive Guardian was, I had to look it up. That's a great idea. I just bought a new coupler and bearing today if I can't find a better shaft soon I'll get one more stock one just because I'm going to Key West poker run with this boat and I'm running out of time. I'll be looking into a drive guardian for next years boating season. Thanks for the idea.

I'm glad I'm not the only person having this problem. I'll have to look to be sure but I don't think the shaft goes through the coupler far enough to reach the crank. I'm not even sure it's pilot bushing in the crank but I'll look to be sure. Thank you

simple...heavy boat, twins, tons of load...how hard are you hammering it getting on plane ? rule of weight/load/power here...

Good luck, totally different that i was thinking. When i bought my steelings box it came with a staggered boat drive shaft, it used no coupler or splines, instead ot had a h coupler that bolted directly to flywheel with a crank button, it used 1450 series u joints and a super heavy duty driveshaft which are the baddest as thing out there, maybe you could convert?

I don't know if this what your set up looks like, but this is the arrangement used on a 525 drivelive
https://www.mercruiserparts.com/Show...ecting+Rods%29

they list a pilot bushing as being used for a drive line

this is a breakdown of the shaft arrangement
https://www.mercruiserparts.com/Show...nts%28Bravo%29

I don't have to hammer it to get on plane the drive hight is so high that hammering it wouldn't work. 2,000-2,300 RPM's will get on plane

Yes that is the same set up I have in my boat. The shaft that goes in the coupler is the one I keep breaking.

Mine also has a coupler that bolts to the flywheel and a splined shaft the goes in the coupler the other end of that shaft hooks to a driveshaft and the driveshaft runs aft to the input shaft of the drive.