Transmission Slipping?

So I spoke to a mechanic here today and he said to try the following:

1. Put the drive in reverse (It should be locked in drive in both directions)
2. Apply pressure to the propeller and see if it turns the engine over or slips, this should tell you if the coupler is damaged

Well I did this and found one of two things, the engine turns over when I turn the prop clockwise but when turned counterclockwise the outdrive clicks and does not engage fully when in reverse. Unfortunately I forgot to put the drive in forward to test that direction. It seems the coupler might be fine but the outdrive may have issues. Any thoughts?
 
Confusing!!!!!!

On land, motor off, keys out of the ignition, and shifter in reverse, the prop shouldn't be able to move in one direction (or with enough pressure, may be able to turn the engine over) and should click in the other direction. Same for forward, only the opposite rotations.
 
Quite the conundrum. Would there be any chance that grease from the gimbal bearing could be getting to the coupler causing it to slip? I know that I just greased that bearing.
 
Grease would have no affect on the coupler as it is splined. I'm amazed that you can generate enough torque to actually rotate the engine using only your hands on a 17-19" prop. Did you have someone in the bilge to confirm the crankshaft is rotating?
 
I was lucky enough to have the lettering on the belt for the alternator to be located at the water pump. I used my foot to get it to turn. Very difficult to do but the engine turned over. The way I knew the engine was turning over was that the lettering from the alternator belt was in a different location.
 
What if the outdrive shimming was incorrect on the bottom end. Could this cause it to slip out when the prop is tightened down?
 
Sounds to me as though the prop is ventilating. Here is what happened to a friend. Took his boat out with the kids. Spent the day swimming around the back of the boat. One of the kids stood on the sounder transducer and it folded down a bit, like only an inch. Coming home the boat would get on the plane then as the speed increased she would then suddenly slow down and the engine revs. went through the roof. Just like all of the above. Did all the checks as above, nothing found. Straighened up the transducer, problem went away. We figured the transducer was upsetting the water flow from under the boat and the prop started sucking air when she was on the plane. Strange things happen.
 
that doesn't answer why it won't go above idle speed with the one prop.
 
There is no transducer in the way. The only items that stick below the boat are the speedometer pickup, outdrive, and trim tabs. Could the adjustment be off on the shifting mechanism causing it to slip out of gear?
 
I guess it could be the shifter cable not keeping the OD in gear, but again, that doesn't explain your low speed issue with the one prop.

I just found my old Alpha shop manual the other night (while I was looking for my old smartcraft manuals for another member...which I still can't find). If I get time, I'll scan through it and see what it says.
 
osd9 said:
I just found my old Alpha shop manual the other night (while I was looking for my old smartcraft manuals for another member...which I still can't find). If I get time, I'll scan through it and see what it says.
Click to expand...

Well, talked to another shop today and they said to check the coupler because it is probably 95% done and could fail at any time. I will let you guys know what I find out.
 
Quick question for everyone, when the coupler goes bad is it just the teeth on it that go or does the rubber inside the steel/aluminum housing start to slip as well?
 
does anyone have any pictures what the coupler should and should not look like? I just purchased the alignment tool and I am going to pull the outdrive this weekend but I would like to know what I am looking for.

Thanks
 
jamfred said:
does anyone have any pictures what the coupler should and should not look like? I just purchased the alignment tool and I am going to pull the outdrive this weekend but I would like to know what I am looking for.

Thanks
Click to expand...


I don't have any pictures but once you clear the grease from the coupler you will see the teeth. If they are square,, the gears are ok, if the are V shaped on the end your coupler is shot. I don't know how they check the rubber portion though.
 
Well, it has been one heck of a ride but I finally found the problem. Neither the engine nor the outdrive has any problems what-so-ever. Thanks to a cavitation thread http://clubsearay.com/forum/showthread.php?t=19199 I found these issues:

New Prop - 13.75"x15p

Severe Cavitation issue, boat will not do anything other than barely move and then rev up. The prop does not have a large enough diameter to propel the boat. I was informed by a prop shop that this size of a propeller is used on outboard engines and not I/Os. I should have called them first but I relied on the individuals at west marine instead. I will not make that mistake again.

Old Prop - 14.5"x17p

Slight ventilation issue due to a damaged prop. I found out that the cone on the back of the prop cracked and came off causing ventilation at around 3000 rpm. A new prop will fix this or just re-welding the cone back on.

Thank you to everyone for helping assist me on this issue.
 
Thanks for following up with the actual cause. Glad to read that your fix is a cheap one.
 
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