Alpha One Gen II drive slipping under load

[jvendlin]

I have a Mercruiser 5.0L MPI with an Alpha One Gen II drive (used 2007 Sea Ray 210 Select, bought last year). At the end of a day of skiing I was going slowly then tried to bring the boat on plane and the RPMs when up but speed didn't increase. I stopped then reversed and that seemed to fix the inability to get on plane but there was a lot of vibration. I made my way home, checked the prop, no issues but swapped it for a different prop and replaced the Delrin bushing just in case. The next time out I made it a few miles and the same thing started happening. I could go slow but as soon as I applied more throttle to get on plane the RPMs went up but no power at the prop. I crawled in, checked the prop, it's not spun, then pulled the outdrive thinking it might be the splines on the engine coupler but they're pristine and I didn't smell any burning rubber at any time. Everything obvious seems to be in tip top shape. Prop not spun, coupler seems ok, no debris on the prop. Any ideas?

 

[Pmt133]

If you can get to it easily, mark the engine coupler with a marker relative to the hub/spline and see if it moves. If something in the drive were causing that I'd imagine you'd probably hear it making a racket....

 

[nola mike]

I have a Mercruiser 5.0L MPI with an Alpha One Gen II drive (used 2007 Sea Ray 210 Select, bought last year). At the end of a day of skiing I was going slowly then tried to bring the boat on plane and the RPMs when up but speed didn't increase. I stopped then reversed and that seemed to fix the inability to get on plane but there was a lot of vibration. I made my way home, checked the prop, no issues but swapped it for a different prop and replaced the Delrin bushing just in case. The next time out I made it a few miles and the same thing started happening. I could go slow but as soon as I applied more throttle to get on plane the RPMs went up but no power at the prop. I crawled in, checked the prop, it's not spun, then pulled the outdrive thinking it might be the splines on the engine coupler but they're pristine and I didn't smell any burning rubber at any time. Everything obvious seems to be in tip top shape. Prop not spun, coupler seems ok, no debris on the prop. Any ideas?

Either your coupler, broken driveshaft, or wiped out gears. Coupler sounds most likely still. Pull the top cover on the drive to check the gears, and/or pull the drain plug to check for metal.

 

[jvendlin]

Thanks for the input guys. I think I figured it out. Turns out it was a combination of bad luck and terrible troubleshooting. On my first outing I had just been through a patch of seaweed, hence the throwing it in reverse cleared the issue. When I got back on shore I inspected the prop to make sure it wasn't spun and it was not so I chalked it up to the seaweed. I did also however put on a different prop that had a new bushing in it just to be safe. When I had that second issue yesterday I just assumed it wasn't the prop bushing because it hadn't been the previous time so I panicked thinking it was some major issue and went about pulling the whole drive off and not finding anything wrong. This morning I must have had my wits about me a little better and I pulled the prop. Sure enough the bushing was shorn so that second time out I had spun the prop (it was a cheap knock-off bushing off of Amazon too, will never do that again).

Seems like bad luck to have a debris issue and spin a prop on two sequential outings but I definitely flubbed it not pulling the prop on the second one.

Thanks again.

 

[nola mike]

Thanks for the input guys. I think I figured it out. Turns out it was a combination of bad luck and terrible troubleshooting. On my first outing I had just been through a patch of seaweed, hence the throwing it in reverse cleared the issue. When I got back on shore I inspected the prop to make sure it wasn't spun and it was not so I chalked it up to the seaweed. I did also however put on a different prop that had a new bushing in it just to be safe. When I had that second issue yesterday I just assumed it wasn't the prop bushing because it hadn't been the previous time so I panicked thinking it was some major issue and went about pulling the whole drive off and not finding anything wrong. This morning I must have had my wits about me a little better and I pulled the prop. Sure enough the bushing was shorn so that second time out I had spun the prop (it was a cheap knock-off bushing off of Amazon too, will never do that again).

Seems like bad luck to have a debris issue and spin a prop on two sequential outings but I definitely flubbed it not pulling the prop on the second one.

Thanks again.

Glad you got it sorted. Troubleshooting is tough when you have faulty replacements.

 

[cyclops222]

Fall coming on us. Watch out for patches of weeds floating around. Can cause noisy and slipping props. Also pieces of floating boat lines.