'58 Lark gearcase dry as a bone

[DavesInvader]

Opened up the gear case tonight. Not a drop of oil in sight. In fact a nice thin coating of rust on everything! Probably had water in it at one time.

Pics here:
http://mysite.verizon.net/res78w95/boat/id2.html

I made the P.O. run it in a tub and it seemed to work fine. He said it ran last year but they couldn't get it over 15 mph. That's probably because he was welding the bearings to the prop shaft! They're stuck tight to the shaft, can't get them to roll/slide at all. Anyone see an alternative to finding a replacement gear case?

 

[tx1961whaler]

Re: '58 Lark gearcase dry as a bone

Anyone see an alternative to finding a replacement gear case?

No, not really.
Since it looks pretty well ruined, you might try soaking the parts in a bucket of penetrant to see if it loosens up and you can salvage some spare parts. There is a possibility that the PO just drained the oil and didn't put any back in, and it's surface rust, but probably not.....a good penetrant is a 50-50 mix of ATF and acetone; but use it outside and away from flames. Nasty stuff.

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

Thanks. I have it soaking in a combination of Rust Eater and WD40. Probably not the best idea but I figured I didn't have much to lose. My main goal is to get the ball bearings off to see what damage the shaft has. But even if the shaft is usable, my internet searches aren't turning up replacements for one of the two ball bearings (part no 20X52). The other (375761) is available but pricey. I'm probably getting ahead of myself anyway.

By the way, were any of the gears/bearings, etc pressed onto the prop shaft or would a normally good prop shaft/gear assembly just slide apart? I'm not sure what I'm up against in trying to get the shaft disassembled so I don't know if I'm fighting rust or things are tight because they are supposed to be.

Thanks!

 

[samo_ott]

Re: '58 Lark gearcase dry as a bone

Good pics. rough time with the engine though. So you saw it running with the P.O.? did he shift the gears? did they work? I have a 57 35 but have not opened up the LU yet. In other smaller engines all the gears should slide freely on the prop shaft.

You did not have a pic of the stuck bearings on the driveshaft. Will heat help take them off?

 

[Lion hunter]

Re: '58 Lark gearcase dry as a bone

You could build an electrolysis tank to clean up all the rust. Get a big tub of water and add some type of electrolyte (washing soda which is sodium carbonate) works the best. Get 2 strips of stainless steel and hook them to a battery or charger on low amps, place positive and negative on opposite sides of the tank and turn it on. It works great. Do it outside and no open flame as you are creating hydrogen gas. Also do not use any type of sodium chloride or anything with cholrine in it, it will create chlorine gas. Very bad.

 

[tmcalavy]

Re: '58 Lark gearcase dry as a bone

Ugg...worst case scenario. None of the bearings are pressed to the shaft, they should slide right off. If soaking in penetrant doesn't work, you need to post a wanted ad on the Webvertize ads at www.aomci.org
Look for a complete LU...generally not hard to find. Make sure you get 58 Lark gears or LU...there were differences in engineering among OMC models in the late 50s.

 

[lindy46]

Re: '58 Lark gearcase dry as a bone

By the way, were any of the gears/bearings, etc pressed onto the prop shaft or would a normally good prop shaft/gear assembly just slide apart? I'm not sure what I'm up against in trying to get the shaft disassembled so I don't know if I'm fighting rust or things are tight because they are supposed to be.

Thanks!

All those components just slide on and off the shaft. BTW, I can probably help you on those parts. PM if interested or e-mail me.

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

A little luck/progress this morning. After soaking overnight, the gears now spin easily on the shaft. I'm starting to think the P.O. probably had drained the oil for the winter and ran it without oil to show me, forgetting he'd drained it, so the bearings are probably fused to the shaft.

Anyway, the bearings are still stuck tight, so I'll give them more time. What's the rule on replacing the gears/shaft? I know the gears are matched to each other, but is the shaft matched to the gears too, and the case? Or could I just get a replacement shaft and bearings and keep the old gears if they're in good shape?

Thanks to all for the help!

 

[R.Johnson]

Re: '58 Lark gearcase dry as a bone

The crack's in the mounting bracket would be my concern before buying anything. That engine had to have hit something very hard to do that. The look's of the fuel pump, and cylinder head makes me wonder if there is rust inside the engine also. If there is, you have a replica of a 58 Lark.

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

Yeah, if I knew then what I do now I doubt if I would have gone for this boat. Already have a replacement bracket. The stuff in the fuel pump was calcium buildup, same for the compression chamber. I did get another head because the original had a botched thread repair job on one spark plug hole that was beyond fixing. The water passages inside the engine block were much better than I expected. No rust and just a few small calcium deposits. Crankcase and finger valves were beautiful. It looks like the head gasket had failed. Anyway, that's interesting, I didn't know they made replica Larks. You learn something new every day!

 

[R.Johnson]

Re: '58 Lark gearcase dry as a bone

They did'nt make a replica, that was up to the owner. I have seen any number of replica's. They are not rare.

 

[rolmops]

Re: '58 Lark gearcase dry as a bone

That lower unit is toast,don't waste your time on it.There very many lower units of that era available, often for free.
The Johnson/Evinrude '56 30horse,the '57 35 and the '58 35 are all the same lower unit.The '59 and '60 are a bit different but they do fit and they will do the job.

 

[R.Johnson]

Re: '58 Lark gearcase dry as a bone

We once had a big twin come into the shop after a blow like. Did the gearcase repair, put in the test tank, with test prop, brought it up to full RPM. It spit a smoking chunk of connecting rod clear across the shop floor.

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

Thanks guys. I guess my optimism got the best of me. It sounds like the general consensus here is not to mess with it and find a replacement. Guess I'm going shopping. I was feeling pretty good about it yesterday. Had everything moving but didn't have the bearings off yet. The gears and clutch dog are in beautiful shape, so I know they are salvageable.
thanks

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

Found a Johnson RDS-21 lower unit locally. Looks the same on the outside, anyone know if this'll work on my 58 Lark? I know they share many of the same parts, but don't know about the LU.
Thanks

 

[tmcalavy]

Re: '58 Lark gearcase dry as a bone

Does your Lark have one or two water tubes from the LU to the powerhead? If it has two, the RDS-21 LU will work. They changed the design/engineering in the late 50's...can't remember when. Can't tell from your photo link if you have an old-style Lark or one with the white, super-quiet housing and white fiberglass hood/top.

 

[samo_ott]

Re: '58 Lark gearcase dry as a bone

Thanks guys. I guess my optimism got the best of me. It sounds like the general consensus here is not to mess with it and find a replacement. Guess I'm going shopping. I was feeling pretty good about it yesterday. Had everything moving but didn't have the bearings off yet. The gears and clutch dog are in beautiful shape, so I know they are salvageable.
thanks

I'd try it. I'm that type. Soak the whole thing in oil. If it loosens up I'd try it. You have little to lose if you're assuming it's already toast. But it must all move freely.

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

It does have the two tubes. It is not the superquiet version. Mine has the aluminum cowl. I believe 58 was the last year.

Sam, it has loosened up quite a bit, and honestly, I'm that type too. My only hangup right now is the bearings. The one on the prop side will spin now (but does sound like there's grit in it) but I can't get it to budge laterally. In other words, I'd like to slide it off the shaft but it won't move. The one on the other end will spin and I can move it but when it gets to within about 1/8" of the shaft it gets stuck no matter what I do. Even tried a torch on it and it didn't help. I may have to destroy the old bearings to get them off in order to replace them. Either way it isn't going to be pretty, so I'm about to admit defeat.

To make matters worse, I noticed a small crack in the skeg, which goes through to the inside where the gears are. If you look closely at my pics you can see it. So I'll need to weld or replace it. So that really adds to why I think I'll just be better off replacing the whole mess. I guess what bugs me about the whole replacement idea is the thought that I'll be replacing it with someone else's mess. But I guess I have nothing to lose.

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

Finally got the bearings off tonight. It took a little persuasion with my bench vise and a hammer. The shaft is toast. The areas where the bearings were are heavily scored and even pitted, so I've convinced myself a replacement LU is where I'm headed. As I mentioned before, the gears are in beautiful shape after getting the surface rust off them and so is the shift dog. So I have a good spare set.

 

[DavesInvader]

Re: '58 Lark gearcase dry as a bone

Found a very nice almost new old stock lower unit today, within driving distance! Found a retired, previous Evinrude dealer who had a factory replacement lower unit sitting in his garage. It still had the primer on it. Said it had been used a few times on one of his motors then taken out of service. Very little evidence of use. Looks like it all should fit together and it was a very reasonable price. I'm feeling very fortunate today!