1958 Evinrude Lark question

242ab

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Hello all! I have a 1958 Evinrude Lark 35 that came on a 1958 Bristol Bluefish. I have begun to restore the rig and have torn the motor down. Before doing so, I did a compression test and it had 120 on the top cylinder and between 110 and 115psi on the lower. When I removed the head, the lower cylinder does have some mild scoring on the exhaust side of the piston and cylinder wall.

Anyway, my bigger problem right now is that (7) of the exhaust cover bolts and (3) of the bolts mounting the block to the lower unit broke off during disassembly. Successfully getting all 10 out has me concerned, so I am considering "plan B". I have a perfect 1967 Johnson 40hp. Is it possible to use the powerhead from that and bolt on all of the '58 parts? The two visible differences are the exhaust cover (no provision for fuel pump, but bolt pattern of the '58 cover is identical) and the head which doesn't have the compression release. Internally, I did find specs that the 40hp has a slightly larger bore.

Here are some picture of the boat and motor:

photo1.jpg


photo2.jpg


IMG00304-20110509-1545.jpg
 

1946Zephyr

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Re: 1958 Evinrude Lark question

Yes, I have actually done that myself. To be exact, I bolted a 1968 Lark powerhead on a 1959 Johnson RDS-21 and it worked great. Funny, I did reverse what you want to do :D
 

242ab

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Re: 1958 Evinrude Lark question

Thanks Zephyr! Aside from the larger displacement, is there anything contributing to the 5hp increase? More displacement would logically seem to need more fuel. Can I use the reeds and carburetor form the 1958 35hp without issue?

I would like it to look 100% like a 1958 when it is complete.
 

lindy46

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Re: 1958 Evinrude Lark question

If you have that great a compression, why would you want to tear that motor down???
 

242ab

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Re: 1958 Evinrude Lark question

Two reasons really. First, I want to make it "like new" both visually and functionally. The boat is being media blasted down to bare wood to be refinished and the motor should be done the same way. When people talk "restoration" it can mean many things. To me, restoration means taking it back to the day it was made- sometimes even a little better.

Secondly, I want 100% piece of mind that it is right. I will run this boat with my father, wife and kids when it is completed. Normally, I would just go buy a new Etec, but the boat is too correct to mess it up like that. Tearing it down and inspecting it piece by piece, replacing all gaskets, seals, ignition, etc. is the best way that I can make it to like new condition.

I know, I know, if it isn't broken- don't fix it. I'm going with the "fix it first before it breaks" theory. With a 53 year old motor that appeared to have never been apart, I didn't know what it was hiding. I got the boat from the original owner's niece. It had been stored in a garage since 1983. Her uncle used in the boat almost exclusively in salt water around Cape Cod. The bolts that broke, broke with almost no effort. They were very corroded. The exhaust tube that goes through the mid section was VERY corroded as well. It is missing a piece larger than a quarter. These are things that would have most likely failed in the very new future. I was least concerned with the compression and more concerned with the things that have already happened- broken corroded parts.

Here are a couple pics of what it looked like before I tore it down:

DSC_0480.jpg


This was after a quick degrease. Notice the paint loss at the top of the cylinders and on the head where you can see the red primer. My concern here is that it may have been run a little hot a few times. Perhaps it's just normal for the age, but a sign of heat for sure.

DSC_0485.jpg


This is the exhaust cover which was obviously replaced at some point. Seems like an odd hard part to be replaced, but being it's painted a Johnson color, I have to suspect it indeed was replaced. Ironically, this is where I had most of the bolt problems. Notice the rust on a lot of the bolts.
 

242ab

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Re: 1958 Evinrude Lark question

Here are some pics of my potential "donor" motor. It's a 1967 Johnson Super Sea Horse 40hp, Manual start, Tiller. As you can see it has VERY low hours and has been serviced within the past two years. Best part- my cousin gave it to me- yahoo! It's kind of a sin to tear it apart, but it could quickly solve my problems and I know it is good.

photo3-1.jpg


photo4.jpg
 

Mas

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Re: 1958 Evinrude Lark question

Well, now that you're are already into the motor, I would just take the block to a machine shop and have the broken bolts removed correctly. You can very lightly hone the cylinders and re-ring to make the block very reliable.

You are correct..restoration means different things, but I believe you will arrive at a better conclusion using the original block.

Mas
 

242ab

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Re: 1958 Evinrude Lark question

That is my other option Mas. The purest side of me wants to do just that. The only internals that seem to be available are the rings, so a hone job and new rings would be it. Probably my best option, but the other power head is VERY tempting.
 

Mas

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Re: 1958 Evinrude Lark question

Try marinengine.com or sea-way.com

They will have what you need. I have acquired a 100% totally new powerhead for my 1957 Evinrude 35hp from these places...block, crank, pistons, rods, rings bearings, seals...you name it, it can be found!

P1030134-1.jpg


Mas
 

242ab

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Re: 1958 Evinrude Lark question

WOW! I think I just drooled a little bit. Thank you for the links. I will be checking them out.
 

Mas

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Re: 1958 Evinrude Lark question

Admittingly, the block/crankcase was a score...and probably the most difficult item to find. The rest of those items can be found with little effort.

Mas
 

1946Zephyr

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Re: 1958 Evinrude Lark question

I second that. I bought new pistons, rods, rings and a crank, for my 1941 Johnson HD-20, at Sea-Way Marine. They do have a great stock of parts for these old classics.
 

HighTrim

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Re: 1958 Evinrude Lark question

I just restored (mechanically only) the same motor. Could have saved you a little time and money and sold it to you, lol. :)

I am a bit of a purist, so agree with lightly honing the cylinder and re ring as you have it apart already. Although, with those compression numbers I may have left well enough alone. Understand your reasoning though, been there, dont that. Have rebuilt a perfectly good powerhead to keep me from having to vaccuum the livingroom.

This is the block from my 57 Javelin that I just honed and soda blasted, hard to tell the difference from a brand new one isnt it?

020.jpg

019.jpg

018-1.jpg

021-1.jpg
 

242ab

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Re: 1958 Evinrude Lark question

Great stuff guys- very nice! This is the route I am going to take. It's the right thing to do. Going to get as many internal parts that I can get my hands on and hone the cylinders.

Now I need to find a good machine shop here in NJ.....
 

242ab

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Re: 1958 Evinrude Lark question

Thanks again for the links. They had every internal part- new! I have a choice of standard, .020, and .040 pistons and rings. The block is going to the machine shop this week so I will know if it needs to bored oversize to remove the slight wear in the bottom cylinder. Has anyone done this and is there any issues in going .020 or .040 over from a cooling or reliability standpoint?
 

Mas

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Re: 1958 Evinrude Lark question

You'll want to go with the least metal removal...leaves more metal...for both strength and dissipation of heat. Go with your machinist's recommendation. The term "reliability" will have more to do with your break-in procedures and use of proper oil mix and maintenance than a slight overbore.

Mas
 

242ab

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Re: 1958 Evinrude Lark question

If you have that great a compression, why would you want to tear that motor down???

Well, the tear down is complete! I had a BEAR of a time getting the flywheel off. Heating it finally did the trick.

I can say that I am VERY happy that I tore this motor down even with the good compression numbers. I knew this boat had been used in the salt water of Cape Cod. The first sign of corrosion issues was the bolts on the exhaust cover and bolts that attach the block to the mid section. The next was the oil tube inside the mid section. It was so corroded that nearly 50% of the flange is missing! That didn't seem too bad and I seriously considered not cracking it open....but I did anyway- and it was the right thing to do.

When I took the rod caps and bearings off, immediatly I could see there was eveidence of salt water intrusion. Some pitting on the rod, discoloration and the chromium was basically worn away. The crank revealed the same conditions as well. I've attached some pictures that tell the story well. I believe this motor would have run and most likely would have held together for the minimal use it will see in the future, but you never know.

Cylinders- lower one on the left with some minor scoring. I had 120 on the top and about 112 on the bottom:
DSC_0487.jpg


First area of concern. Corrosion at base of block:
DSC_0488.jpg


Corroded oil tube:
DSC_0489.jpg


Crank, pistons and rods. Notice the difference in color of the back of the piston. Neither of these were cleaned. This is exactly how they came apart. Also notice the difference on the journals. Worn chromium and some evidence of old pitting.
DSC_0490.jpg


Close up of the pistons and rods:
DSC_0493.jpg


So, with the thinning of the wall at the bottom of the block, do you think I should be concerned? Should I find a cleaner one? Anyone got one?
 

1946Zephyr

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Re: 1958 Evinrude Lark question

The corrsion on the bottom of the block wont be an issue. Just clean it up and re-coat it with primer, so it'll be protected. You'll definately want to get a new oil tube. LOL I think if you hone those cylinders up and clean the block up really good, you'll have a fine motor.
 

db6261

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Re: 1958 Evinrude Lark question

Yes, I have actually done that myself. To be exact, I bolted a 1968 Lark powerhead on a 1959 Johnson RDS-21 and it worked great. Funny, I did reverse what you want to do :D

1946Zephyr I need to become your friend as I plan to do the exact same thing as you did down to the same year model motors :)
 

GA_Boater

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