Reinstalling old Merc gearbox

[darnold]

I have been attempting to restore to working order an early edition 7.5 Merc outboard. After replacing the water pump impeller (after I got the engine running by rebuilding the water pump and replacing leaking fuel fittings) I can't get the lower unit back on. Followed manual by having shifter lever in forward and shifter rod rotated counterclockwise as seen from above, but no go on repeated tries. Can someone initiate me into the secrets and alternatives to got this thing back together?<br />It comes to about three quarters of an inch form closure and feel as if the shifter rod is hitting and not going inot place. I really appreciate any suggestions or tricks to help in this situation.Thanks. David

 

[skier]

Re: Reinstalling old Merc gearbox

darnold:<br /><br />It is the shift shaft slpines are not making a meshed connection or the water tube connection or the drive shaft splines are not linning up. If you can, use a flashlight and try and see what it is or have someone else rotate the flywheel slowly while you install. My water pump kit came with a plastic tube that fit on the end of the water pipe so that it was easier to line up.<br /><br />I hope this helps some.<br /><br />Craig

 

[robsd]

Re: Reinstalling old Merc gearbox

I just went through this myself on a 1970 model 110. The lower unit turns on a couple bushings. In my case the bushings are worn a bit..and I mean just a bit. With the motor upside down I thought it would just drop in, I turned it right side up and it still wouldn't go. I determined the stiff shaft was not going in. While I was moving it again I noticed the movement in the bushings (the worst one is the one about midway up on the lower unit, causes the motor to turn from left to right).<br /><br />With one hand sliding the unit in and the other hand wiggling the lower end it popped right back in. I fiddled with for more than an hour.<br /><br />Hope this helps you,<br />Rob

 

[darnold]

Re: Reinstalling old Merc gearbox

Thanks for the advice. I have been fiddlin with this thing for hours and days! I think that thewater tubeis aligning ok and the drive shaft seems to be aligned ok. I have tried rotating the drive shaft as I try to side theunit in but nogo so far. I haven't tried to turn the engine over (power head down?). Rob, would you please tell be more specifics about how you managed the fit with your old 110? Thanks again.

 

[robsd]

Re: Reinstalling old Merc gearbox

There is a bushing on the motor that allows it to turn left and right (normal operation). The lower bushing is just above the cavitation plate. That bushing (on mine) is worn causing the stiff shaft to not line up.<br /><br />Fix the motor to the transon or saw horse or something. Grap the skeg and try to wiggle it front to back. If you notice some movement at that lower bushing then this could be your problem. Wiggle it while your installing the unit. Sorry hard to describe over the Internet.<br /><br />Good Luck,<br />Rob

 

[darnold]

Re: Reinstalling old Merc gearbox

Hurrah! I finally got it back together after taking off the trim cowl and finding was thus enabled to see the hole where the shift shaft should enter the body. The shaft was missing it by about 3/8 ths inch. I was able to get it in only by inserting the gearbox and then lowering the motor from the tilted to the upright position and jiggling the gearbox there, It finally went in. All attempts to move the shift shaft in the tilted position were fruitless, but in the lowered position it went right in with a bit af movement. It does appear that it is the bushings that wear and cause the problem. Thanks for all the assistance. I hope this info helps someone who might be in the same predicament.

 

[Salty Dog]

Re: Reinstalling old Merc gearbox

How did you set the height of the shift rod?