Idea for freeing stuck lower units.

[boatster]

So we've got a few ways established for removing lower units where the driveshaft is stuck in the powerhead:<br /><br />#1 wedges (IF you can get some gap > 1/4 inch) <br />#2 use penetrating oil<br />#3 hit the heck out of it with a mallet.<br />#4 cut driveshaft and reweld.<br />#5 replace destroyed lower unit, or driveshaft, or mid housing, or all of the above.<br /><br />And any other variation or combo of the above listed.<br /><br />I just thought up another one and I would like opinions please. <br /><br />What if you took apart the lower unit gearcase and removed the pinion gear from the end of the driveshaft so that only the impeller housing and impeller lock pin are all thats holding the lower unit on the stuck driveshaft. You would then proceed to wedge and destroy the waterpump housing by driving the lock pin through the top of the waterpump as you pull the lower unit down. <br />Now that you have the lowerunit and eventually the midsection off you can proceed to hopefully convince the driveshaft to come off of the powerhead. How does this idea sound? Anyone done this before? Am I missing any possible complications? Would the driveshaft be somehow bent in the process? Thanks.<br /><br />I say this because I have a acquired an almost mint motor that was neglected for 7 years. It has a stainless driveshaft but nonetheless is stuck pretty bad. Hey I gotta admit I never learn. Either that or I love solving problems. BTW my other Merc 20 is now running beautifully after destroying my midhousing and lower unit. Uhhh thats pretty much 2/3's the whole motor. I got the replacements for pretty cheap. Thank god for donors!!

 

[Chris1956]

Re: Idea for freeing stuck lower units.

Boatster, It is likely your plan would work. How about another suggestion? If you can get a gap between LU and midsection, why not hang the motor upside down, 2 inches off the ground and spray the penetrating oil through the gap, onto the driveshaft. Gravity will cause it to run into the "driveshaft to crankshaft" spline, which is where it needs to be. Also, gravity on the powerhead will help to seperate the two units, and a 2 inch fall onto the lawn will not damage the motor.

 

[boatster]

Re: Idea for freeing stuck lower units.

Chris1956,<br /><br />I might be a bit pessimistic to think that'll work because the only gap I can get is about 1/8" and thats with wedges. This thing is clammed shut. I was thinking of drilling a pilot hole in the midsection so I could spray the penetrating oil then wedge, and possibly hang upside down. I might have to give that a shot before I go to plan B.<br /><br />A little more history on this motor probably would help. Its a 1989 Suzuki DT30 (Moderator: please don't move this to Suzuki forum, I like the merc guys). Anyways the first owners never used the boat for 10 years. The second owner, whom I bought the motor from never changed the impeller for his 7 years of ownership. He said he only used the boat around 30 times 1/2 in lakes 1/2 in ocean. THis gets me worried. Granted its a stainless steel shaft but still thats a long time for binding to get a grip so to speak. <br /><br />I'm gonna be patient on this one though. The motor is in "like new" condition with oil injection and electric start. Not to mention its an inboard control.

 

[quantumleap]

Re: Idea for freeing stuck lower units.

I feel that the added weight of the lower unit attached to the shaft helps to "shock" it free while hammering. I think it would be very hard to remove the bare shaft by itself. What would you hang on to or hammer against??

 

[boatster]

Re: Idea for freeing stuck lower units.

A big table vise to hold the Driveshaft. Or at least you'd be able to wiggle the binding rust free, or torch the binding to maybe expand the metal and break rust bonds. Also you'd be able to see if it were even possible to extract the driveshaft by looking at the severity of the rust. E.G. my 1975 Merc 20 would have been impossible to remove the driveshaft from the powerhead any other way but drills and punches. Way too binded. If hanging by the lower unit, I could still bolt something back into the end of the driveshaft and hang it by that and the weight of the powerhead + whatever else I can attach as weight. Keep the thoughts coming though. Thanks.<br /><br />Adam

 

[andrewkafp]

Re: Idea for freeing stuck lower units.

Boatster.<br /><br />Hindsight is a great thing.. But there are only 2 reasons that the drive shaft gets stuck. 1. Before 1978 the shaft was not stainless steel and 2. The previous owners have neglected the motor by not regularly removing the L/U and the prop for Water/pump service and Prop greasing maintainence. Neither of these can be controlled by you.. the new owner.<br />Even a non-stainless shaft would be quite servicable if removed every second season and re-greased. It's just like someone running the motor with wrong oil/fuel mix for years.. It will just die. I have read most of the posts on Mercs, and there are only a few where the L/U is just dead stuck.. Unfortunately for you. Yours is one of them.

 

[boatster]

Re: Idea for freeing stuck lower units.

Ok,<br /><br />I've been educated. Apparently not all driveshafts and lower units are built the same.<br />Hence, the DT30 isn't as simple as the Merc 20 I have. Its not just a matter of removing the gear on the end of the driveshaft in the lower unit. I'm sure many of the veterans here already knew that. So I am becoming more aware that each motor has their own demons. In my case it seems the best route is to cut the driveshaft through the housing. A new driveshaft costs $140 so I'm not gonna go broke over it. The suzuki shop is only gonna charge me $40 to remove the lower unit gears so I can put the new driveshaft in. The rest will be up to me. I'm lucky because $40 is a drop in the bucket for what he could charge if he wanted to. <br /><br />It is apparent I am very new to the world of outboard motors but I'm learning fast. And as far as I'm concerned if I'm going to store my motors for any extended time, they're going to be seperated and parked. I'm determined not to let any of motors get stuck under my care.

 

[MURX]

Re: Idea for freeing stuck lower units.

Dyanmite works on tilt tubes with rusted cables<br />could do wonders for lowers

 

[emckelvy]

Re: Idea for freeing stuck lower units.

Better watch out, if the driveshaft is stuck that badly in the crank, the crank splines are likely to be rotted away too. Be sure to check the crank splines very carefully before spending money on a new driveshaft.<br /><br />I once had a 9.5 Evinrude that was stuck so bad, even after pulling the driveshaft thru the pump housing (good thing the shaft just slides out of the pinion gear), and pulling the powerhead, I couldn't get the shaft separated from the crank. <br /><br />Had to disassemble the motor, take the crank/driveshaft assy to my machinist buddy and have him press it apart!! Miracle of all, the splines were'nt rusted out of the crank.<br /><br />Seen lots of Mercs with stuck splines, especially the single 4's etc. And the 20's seem to be real bad, too, for some reason. Got one in the garage right now that's that way, I've already cut a hole in the midsection (the previous guy broke it anyway so it doesn't matter), and have been pouring penetrating oil in. Maybe someday it'll even come apart!!!! lol.