Mercruiser Alpha likely outdrive issues

[Jellybelly]

I am helping a coworkers husband rebuild a 1973 sea ray. It has a straight six165hp Chevy engine. I recently replaced the water pump. I never did find the right base and just reused the old one. It was a short and stubby one without a gasket.

Here is a picture of the lower unit. I think it was a replacement lowers perhaps because I’m not sure the square was used then. It does not have the preloaded pin. Now I know what that is.

When we put it all back together, We struggled to get the lower up close to the mid section. Having never done one this old, I thought maybe it was normal. Probably over an inch apart.

we snugged them up evenly but the shift would not return to neutral or go to reverse. I was pretty certain the prop and the lower and upper were in forward. So, I removed the lower again. I had done my best to rotate the prop and keep it in forward. Obviously I must not have done so or screwed some other way.

while mating the lower to the upper The first time, I likely stripped the intermediate Brass shift shaft. There were brass shavings when I took the lower off to try again. No problem, new one is cheap. Looks easy to install too. This time When I reinstall, I’m removing the upper housing too.

but more troubling is the lower unit shift shaft will not turn with my fingers. I can turn it with pliers easily. Is this ok? I remembered before I did the stupid misalign that the shift arm turned easily. Maybe it was as I moved prop. Long day. I am afraid maybe the force of misaligned shift shaft may have damaged it. I can get the lower into forward and reverse with the pliers and turn the prop and it seems to be engaging with a click. I am really hating that I offered to help.

any help would be appreciated. If I have to buy him a new used lower I will. I should have know better. My experience is all in outboards. Not much different down there, but never a mercury.

 

[Bondo]

but more troubling is the lower unit shift shaft will not turn with my fingers. I can turn it with pliers easily. Is this ok?

Ayuh,...... Welcome Aboard,...... It's normal not to be able to manually, with yer fingers, shift it, with just the splined shaft,.....

I use a bungee strap to hold the prop shaft, so it'll stay locked into forward,.....

 

[Jellybelly]

Thank you bondo. I have been reading a learning from you for a long time. It was time I expanded my memberships!

 

[Jellybelly]

Do you think the issue with not being able to shift is because of improper mating of lower and upper? I assume you would agree with me to remove the upper and mate top to bottom. Are there any issues with removing the upper housing? Also, note I must be reading your posts I did not call it a “Pre-alpha)

 

[Bt Doctur]

you never draw the units together or draw the drive on with the nuts. You may have damaged the shift selector in the lower, The splined lower should turn fairly easily using a 1/4 drive socket of the correct size. If you cannot shift into forward, (shift shaft in a straight line) you must remove the lower unit first, then the upper unit

 

[Jellybelly]

you never draw the units together or draw the drive on with the nuts. You may have damaged the shift selector in the lower, The splined lower should turn fairly easily using a 1/4 drive socket of the correct size. If you cannot shift into forward, (shift shaft in a straight line) you must remove the lower unit first, then the upper unit

Yes, I definitely used the nuts to draw together. I know better, but felt rushed and just could not get it to mate. I splined shift selector turned easy with pliers (I didn’t even have to close hard). I will get back at it Sunday I hope. He only has one day off consistently.

I will for sure use the bungee. Do most of you agree I should remove the upper from the upper part of the stern drive and mate It upper to lower off the boat?

 

[Bt Doctur]

That depends on your experiance level . To do it that way, lube the impeller with soapy water, KY, A/F ,etc .You need to turn the shaft backwards and you dont want to reverse the vanes. Raise lower up, turn prop CCW a inch or so to alT ATTENTION ign the shaft while pushing upward.. NOW PAY ATTENTION start the forward nut by a few threads, make sure the upper brass shaft engages the lower spline correctly, easily, and is in a straight line. Start the 2 side nuts and tighten keeping an eye on the upper shift shaft and keeping in lined up in the upper shoe. Tighten the side nuts completely, then the other nuts. Manually test the shifting for and rev. fill with gear oil , install on boat. With control box in ful fwd, and drive in full fwd(shift shaft in a straight line ) install drive

 

[Bondo]

Ayuh,...... Many times, I mount the lower to the upper, on the boat,.......

It's at an odd angle, but I don't have to chase the upper 'round on the bench, when it's bolted to the bell housin',......

BD's done it alot more times than I,...... Follow 'is lead,.....

 

[Jellybelly]

That depends on your experiance level . To do it that way, lube the impeller with soapy water, KY, A/F ,etc .You need to turn the shaft backwards and you dont want to reverse the vanes. Raise lower up, turn prop CCW a inch or so to alT ATTENTION ign the shaft while pushing upward.. NOW PAY ATTENTION start the forward nut by a few threads, make sure the upper brass shaft engages the lower spline correctly, easily, and is in a straight line. Start the 2 side nuts and tighten keeping an eye on the upper shift shaft and keeping in lined up in the upper shoe. Tighten the side nuts completely, then the other nuts. Manually test the shifting for and rev. fill with gear oil , install on boat. With control box in ful fwd, and drive in full fwd(shift shaft in a straight line ) install drive

I think I need the mistyped words. Sometimes when i text it is understandable, but that part looks to crucial. Water pump is snugged up. That is what I had experience in. Not mercruiser and not a spline to brass shift rod.