Cant get my merc lower unit to go back on

[NMplayer]

I think its funny that the post beside mine is about the same motor.<br /><br />I have a 1970 50hp merc.<br /><br />I'll try to provide as much info as I can, and I'm doing everything as per the manual.<br /><br />I pulled the lower unit and replaced the impeller (had a broken spline) The water tube stayed in the power head, so I left it there. The motor and the gear case is in forward.<br /><br />I lubed the end of the water tube and the splines on the drive shaft but I still lack a little better than an inch of getting it to mate back up with the drive shaft housing. <br /><br />I know I'm getting the drive shaft to at least partially mesh with the crank because I can feel the resistance at the prop. I'm lining the water tube up with the pump shaft housing and its starting to go in. I'd sure appreciate any help.

 

[mellowyellow]

Re: Cant get my merc lower unit to go back on

been there... had a pal turn the flywheel back and<br />forth while I lifted, finally got it in.<br />good luck,<br />M.Y.

 

[NMplayer]

Re: Cant get my merc lower unit to go back on

Thanks I'll sure try it.

 

[Boatin Bob]

Re: Cant get my merc lower unit to go back on

I had the same problem last year with 1976 150 Merc, I know the books and everyone else says to put the control and the shift shaft in forward. I struggled with it for hours and finally tried it with the control and shift shaft in neutral and it just popped right in, it went in so slick that I thought something else must be wrong, anyway it ran all last summer with no problems, so sometimes you have to think outside of the box...good luck!

 

[NMplayer]

Re: Cant get my merc lower unit to go back on

I'll give that s try too. I sure appreciate the help.

 

[KennyKenCan]

Re: Cant get my merc lower unit to go back on

Make sure you did not apply too much grease to the splines.<br /><br />Too much grease will cause a hydrolic effect on the shaft and prevent it from going in all the way.<br /><br />Just need a light coat of grease to prevent corrosion.

 

[NMplayer]

Re: Cant get my merc lower unit to go back on

I don't think I put too much on it, but I'll make sure.

 

[DanMcK]

Re: Cant get my merc lower unit to go back on

Try pushing down on shifter, then turn the prop as you insert drive shaft, line up water tube. No need to turn fly wheel if you are working by yourself. If your prop is sharp wear gloves. Works for me. Also Keep motor as low as possibe, so shaft stays fairly straight. Good luck, You can do it!

 

[rickdb1boat]

Re: Cant get my merc lower unit to go back on

Like Dan said, I've always had better luck when the lower unit is in a more vertical position. Just seemed to line up easier.

 

[NMplayer]

Re: Cant get my merc lower unit to go back on

Thanks for the tips guys. I'm gonna get at it again after work. The time changed Sunday so I've got another hour of daylight than I would've had

 

[ledgefinder]

Re: Cant get my merc lower unit to go back on

There are 2 splined shafts - driveshaft & shiftshaft. Did you rotate/wiggle the shift shaft as well? The easiest access is behind the transom clamps.

 

[NMplayer]

Re: Cant get my merc lower unit to go back on

I tried moving it a little at the bottom, but I'll try moving it the way you suggedt.

 

[NMplayer]

Re: Cant get my merc lower unit to go back on

I just wanted to let you guys know that I got my L/U in last night. I'm not sure which of your suggestions made it happen because we sort of did them all at once and then after a little bit, it just slid in.<br /><br />I want to thank you for the help. The folks on this board have kept me on the water and saved me hundreds of dollars that I really don't have. (Thats why I continue to work on 30 year old motors) I've been trying to buy from iboats when I can and I would suggest that especially the new forum members do the same. It isn't free to keep this forum here. Show your support to the company that makes it happen. Besides they sell good stuff.<br /><br />OK I'll get off of the soap box now. Thanks again for the help.

 

[bigfishsmallpond]

Re: Cant get my merc lower unit to go back on

I just had the same problem on my '85 black max 150. After three days of struggling, I noticed that the copper water tube was mushroomed out and was not seating in the hole in the upper unit. I straightned the tube, and seated the tube in the upper unit before attempting to replace the lower unit. Like butter!!!!