'58 Johnson 35 lower unit removal

[dostoy320]

Hey guys... <br /><br />So, I tried to drop the lower unit on my 1958 Johnson 35hp Seahorse, but I got stuck. Now, I'm still working without a manual here, so let me apologize for that in advance...<br /><br />I took out the seven bolts that hold the housings together, and the lower unit dropped down about two inches. I could see the rod for the shift mechanism, what I assume is the drive shaft behind it, and a pipe (hose?) that I'm guessing moves water from the pump up to the engine. I took the access panel off of the side of the upper housing that allows one to reach a clamp on the shift rod. It looks like it may be brass(?) with two bolts running through it. I loosened these bolts, and now if I gently turn the LU back and forth I can see that the portion of the rod below the clamp twists while the portion above it does not. This leads me to believe that this is where the shift rod seperates, but even with the bolts loose, the LU wouldn't drop out. I didn't want to tug too much on it until I was sure nothing else was holding it up. <br /><br />From what I've read on here, the driveshaft is connected via a spline, correct? So that should just slide apart? And it looks like that hose/pipe just slides out of the water pump housing? Is this brass clamp on the shift rod the only thing holding me back? Is this the right place to seperate the shift mechanism? Any special trick to getting this clamp to let loose?<br /><br />Thanks a lot gentlemen...<br /><br />By the way, I'm in there to replace the impeller...

 

[K Hultgre]

Re: '58 Johnson 35 lower unit removal

Been a long time since I've worked on one of these. Start by taking the lower bolt out of the shift rod clamp. I think the shift rods are grooved where the bolt goes through requiring the bolt to come out before it will let go. During reassembly make sure to use some grease or something to aid in holding the bolt on to the allen wrench otherwise you'll be dropping the lower unit again to get the bolt back.<br /><br />BTW how does the LU lube look. If its milky, now would be the time to reseal the LU.<br /><br />Good Luck.

 

[Paul Moir]

Re: '58 Johnson 35 lower unit removal

Surpise! You have to completely remove one of the two bolts in the shift rod 'clamp' (actually a 'connector') for it to separate. You'll see what I mean when you get it apart.<br />If the lower unit has moved more than 1/8", then the splines are already loose. You're on the home streach now. <br /><br />Good luck!<br /><br />EDIT: Pardon the post collision, Kevin H. Looks like you won.

 

[dostoy320]

Re: '58 Johnson 35 lower unit removal

Hah! You guys are great! I post a message, hop in the shower, and have two responses waiting for me when I get out.<br /><br />Kevin - yah, the lube looked pretty bad, and I had about half a cup of water in there too. Are you talking about resealing around the top of the LU housing? I wondered if the water pump may have leaked into the LU as well...<br /><br />Ok... last question for this project (I hope): I foolishly removed a small screw near the bottom of the LU which seemed to have been holding some shift linkages in place. Now, when I was younger and I worked on this motor, I remember doing that once because I thought that screw was the oil drain screw. I had a hell of a time getting it back in then and I'm having a hell of a time getting it in now. Any advice? Will it be easier to jiggle back into place once I have the LU removed?

 

[Paul Moir]

Re: '58 Johnson 35 lower unit removal

It's not that hard to get the shift fork hole lined up when you have the lower unit off, since you can manpulate it the shift rod with one hand while looking straight down the hole under good light. <br />But as for the water in it, looks like now is the time for a reseal. If I were you, I would put the shift fork screw back in, rig up some way to blow air into the lower unit through the vent or oil fill hole, and submerge the lower unit looking for bubbles. Bicycle pumps and artfully carved tire valve stems work good for this, as are Just the Right Diameter rubber hoses. If the leak is bad enough, it will turn up under lung power. Be gentle with the pump if you use one - no more than 15psi.<br />There are quite a few seals on the gearcase. There's the cap 'spagetti' seal, the o-ring around the prop seal carrier, the prop seal (often destroyed by fishing line or other debris), the driveshaft seal just under the propshaft, the shift rod seal, and the fill/drain screw seals. Any of these can be leaking, and it's best to know which before resealing the lower unit.

 

[dostoy320]

Re: '58 Johnson 35 lower unit removal

I think I've got just the thing for the underwater pressure test... Thanks for the advice Paul. Can you buy kits that contain all the LU seals, or does one just replace whichever is bad?

 

[K Hultgre]

Re: '58 Johnson 35 lower unit removal

Find the leaky seal. Then reseal the whole lower unit and re-do the pressure test. <br />If it has never been apart in its 36yrs of service you may want to do a visual inspection of the gears and bearings.<br />But first get a "good" manual.

 

[dostoy320]

Re: '58 Johnson 35 lower unit removal

I'm not looking at it right now, but it seems to me that there was no seal/gasket between the LU housing and the rest of the motor. When I reassemble, do I just put this back together metal-on-metal, or should I smear some gasket sealant on there, or is that a bad idea?

 

[Paul Moir]

Re: '58 Johnson 35 lower unit removal

I'm 100% with Kevin on that. Find the problem, then replace all the seals anyway. That's just in case the leak is from somewhere really odd - say the cap seal leaks, caused by an impact.<br />Iboats or NAPA autoparts 18-2686 has all the seals you need, including a couple new drain and vent screw gaskets. You'll also need some sealer. The OEM method is to use 1000 Sealer, but I've found Permatex Aviation form-a-gasket sealer works well in this application too. Just stay away from silicones.<br />Fortunetly, the manufacturer of the bearings used in the lower unit are still being made, and aren't horribly expensive. <br />And get that "good" manual!

 

[Chinewalker]

Re: '58 Johnson 35 lower unit removal

There is no goop or gasket between the lower unit housing and the exhaust housing - just metal to metal. You will need the 1000 Sealer Paul mentions to re-goop the bullet/gearcase portion of the lower unit back together. I also like to run a bead of sealant under the waterpump wear plate as that is where the water comes up from the intakes for the pump.<br />- Scott

 

[petrolhead]

Re: '58 Johnson 35 lower unit removal

Why "stay away from silicones" Paul?

 

[Paul Moir]

Re: '58 Johnson 35 lower unit removal

Just force of habit petrolhead, and what I've had recommended to me here. It's probably not as big a deal like it is with the powerhead seals, where there's exposure to gasoline which turns silicone to goo. Of course, you've probably got to use on of the high-performance, extremely oil resistant RTVs.<br />I don't know for a fact that silicone won't work. I do know for a fact what I suggested does.<br /><br />PS - I also put the bead on the waterpump wear plate like Chinewalker does, but others here with lots of experience don't.

 

[petrolhead]

Re: '58 Johnson 35 lower unit removal

I used Dow Corning Marine Silicone Rubber Sealant to bed the spaghetti seal in my gearcase, it says on the tube that it's suitable for "making gaskets in situ for water pumps, exhaust systems etc.", I guess I'll find out soon enough if it's OK for gearcase seals too!<br />I've used it to bed the waterpump baseplate too, I can't see it being a problem there where it's only exposed to water?<br />I agree I'd never consider it for powerhead seals, or anywhere it would be exposed to high temperatures or very high pressure.

 

[dostoy320]

Re: '58 Johnson 35 lower unit removal

Yeah... I've always been a big fan of that aviation form-a-gasket stuff, which is what I used today when I closed my LU back up. I did run a bead under that wear plate too, just seemed like a good idea. It looked like someone had been through it not too long ago and used some rather questionable sealant that was all brown and brittle and a pain to clean off.<br /><br />The reason I couldn't get that screw in for the shift fork was because the assembly had fallen apart inside. It was really fun tearing the LU down and learning how that all works. I always feel more comfortable running something after I fully understand how it functions. Hope to get out to the lake on Wednesday! Woo Hoo!!!!

 

[K Hultgre]

Re: '58 Johnson 35 lower unit removal

What lake you going on. You only have 10,000 to chose from.