Mercruiser lower unit install problem

[jpopp]

Replaced impeller/water pump assembly, have I-MR drive. Have it in forward I believe, spin freely clockwise, tough to turn propeller shaft counterclockwise. Have unit up to about an inch below upper and won't go any farther, turning shaft counter clockwise to try and help but won't budge. Never found old O-ring, but pulled out some pieces from upper housing and can't see anything else up there. Any suggestions, just can't think what would hold it back. Thought about taking upper water tube assembly off to try and narrow it down to it or the driveshaft, but don't have a gasket to replace the gasket up there. Any suggestions would be appreciated.

 

[jpopp]

Re: Mercruiser lower unit install problem

Anybody have any suggestions?

 

[qystan]

Re: Mercruiser lower unit install problem

Don't forget to put the control box in forward gear.<br /><br />1. The lower shift shaft needs to be aligned with the U-slot of the upper shift shaft at the bottom of the bell housing.<br />2. Driveshaft is the other<br />3. Water pump transfer tube is the last.<br /><br />While you are at it, don't lose the o-ring between the upper and lower houusing.

 

[Bizmark]

Re: Mercruiser lower unit install problem

I just did mine for the first time yesterday and also had a little bit of a problem getting it back together. I also have an Alpha One MR.<br /><br />It sounds like you're going about it the right way. Just some of the things I'd check.<br /><br />Keep some grease on the shift and driveshaft splines. Spin the prop counterclockwise a little as you lift it in place. Make sure the upper shift shaft is still all the way in forward gear. Check to be sure the water tube is not bent a little or off center.<br /><br />My best suggestion is to have some help as you lift it place. Two sets of hands are better as you lift to make sure everything indexes together. I had mine in my lap for about 5 minutes trying to lift, index, and get a nut started all at he same time. <br /><br />Good luck

 

[Bizmark]

Re: Mercruiser lower unit install problem

I just did mine for the first time yesterday and also had a little bit of a problem getting it back together. I also have an Alpha One MR.<br /><br />It sounds like you're going about it the right way. Just some of the things I'd check.<br /><br />Keep some grease on the shift and driveshaft splines. Spin the prop counterclockwise a little as you lift it in place. Make sure the upper shift shaft is still all the way in forward gear. Check to be sure the water tube is not bent a little or off center.<br /><br />My best suggestion is to have some help as you lift it place. Two sets of hands are better as you lift to make sure everything indexes together. I had mine in my lap for about 5 minutes trying to lift, index, and get a nut started all at he same time. <br /><br />Good luck

 

[zukimud1]

Re: Mercruiser lower unit install problem

tough to turn propeller shaft counterclockwise

It shouldn't turn at all, it should be locked tight when in forward.

 

[Westdevil]

Re: Mercruiser lower unit install problem

I JUST HAD THE SAME THING AND THE TEETH ON THE SHAFT WAS BAD SO CLEAN THE END UP REAL GOOD.MAKE SURE THE TEEH ARE CLEAN AND STRAIGHT HAD TO FILE THE TEETH DOWN<br />THEN IT WENT RIGHT IN

 

[biloxiriver]

Re: Mercruiser lower unit install problem

I recently did this same thing and after talking to a marine mech (brother-in-law) who told me to secure the lower unit in forward(so I put it in forward manually, turned the prop to put pressure on it, and then straped the prop with a bungi to hold it in place)and make sure the shift is in forward, then it just slid right together. But of course I did have a friend helping me; the extra hands are important.