1957 18hp Johnson seized

yam350yfm

Petty Officer 3rd Class
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Dec 26, 2007
Messages
79
I have a 1957 fd11k 18hp Seahorse Johnson motor that last ran in 2004. At that time it needed a tune-up and was taken off the boat and put in a boathouse where it sat until about 1 month ago. The motor was not fogged prior to sitting for a few Wisconsin winters. I tried to pull the motor through and it does not budge. Tried PB Blaster in the cylinders, sprayed in after removing the plugs. Have added more over the past few weeks, still does not budge. Looking for suggestions on how to address this. I have ordered a Seloc manual and will tear down if necessary, but do not want to go that route if it is not needed. I am looking for any help, pointers, suggestions......

By needing a tune-up it would start and run but ran poorly. Coils and points were last replaced in the early 90's. Not sure if the carb has ever been rebuilt, but at a minimum I suspect it needs a good cleaning. I had planned to check the coils, points, carb, etc before finding out it was seized. Is this thing worth the effort, or is it time to find something else?
 

samo_ott

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Jun 18, 2006
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5,125
Re: 1957 18hp Johnson seized

It's worth the effort. Keep soaking the pistons with PB (others will offer other concoctions). Is the engine vertical with the plugs facing up to get the PB all around the pistons? Also, take the pull start off and try to turn with a wrench. Much better application of force.

I just got a '62 25hp Viking unfrozen trying this method. Still not sure if it will run or if there is too much internal rust etc but it turns over quite well right now. Considering I got it seized for $20 I was happy.

Dont put any other loot into it until you unseize it though. In the end you might still have to tear it apart but it is not that hard. Also the crank and rods might also have rust, if so, you're in for more trouble.

But keep PB'ing it and keep trying to turn it a tad at a time. It could take weeks. I also tapped the wrench lightly with a hammer and that was what finally got it.
 

HighTrim

Supreme Mariner
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Jun 21, 2007
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10,486
Re: 1957 18hp Johnson seized

Welcome to iboats. Concerning the tune up, youre looking at spending a couple hundred there. So it depends what the motor is worth to youl. In regards to the overhaul, there are guys on here better suited to guide you. If you are going to attempt it though, I would get an OEM manual to guide you.
 

yam350yfm

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Dec 26, 2007
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Re: 1957 18hp Johnson seized

It has been vertical for some of the time and horizontal some of the time. When the plugs were facing up I filled the cylinder with PB so that I know it was puddled in there. I'll try the wrench on there to see if that can free it up. I assume I want to go somewhat easy as to not damage the connecting rods or bearings. I am not so worried about the rings as those can be replaced if need be.

Thanks!
 

jbjennings

Captain
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Jul 18, 2007
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3,903
Re: 1957 18hp Johnson seized

I had good luck once getting one unfrozen by taking off the exhaust covers on both sides. Hopefully you can see the piston rings if the pistons are frozen in the right place and spray some PB blaster on the ring grooves where it will soak a little faster. I got a mercury mark 10 unfrozen that way but never decided to fix it, especially since I didn't have the special tools needed. I hope you get it fixed...
JBJ
 

yam350yfm

Petty Officer 3rd Class
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Dec 26, 2007
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79
Re: 1957 18hp Johnson seized

Thanks, I'll try that too. Hope I can get this thing to free up without a rebuild. It is for my 13 year old son. We are fixing up an old Lund (Shell Lake) fiberglass boat and want to get it done for this spring. First order of business is getting the motor squared away.......
 

samo_ott

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Jun 18, 2006
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Re: 1957 18hp Johnson seized

I have one of my 18's on a 14' aluminum and it is rocket fast. Personally I would be VERY careful giving it to a 13 year old.
 

Chinewalker

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Aug 19, 2001
Messages
8,902
Re: 1957 18hp Johnson seized

I would not run a motor that has been seized like that until I have disassembled it to inspect the bearings on the crankshaft. You may get it unstuck, only to have the motor grenade on you when the watermarked bearings start coming through the side of the crankcase...

I would disassemble it and find out exactly where it is stuck. Make sure you rule out the lower unit. Is there ANY play whatsoever in the crankshaft? If so, that may indicate that it is only the pistons that are stuck and you may get lucky. I'd still at least pull the intake manifold and inspect the rod bearings...

- Scott
 

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
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51,019
Re: 1957 18hp Johnson seized

have you drop the lower unit to see if the power head is siezed or is the lower unit siezed. if the lower is siezed the powerhead will not turn. your powerhead may be fine.
 

Lakester

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Joined
Nov 17, 2007
Messages
428
Re: 1957 18hp Johnson seized

hello,

a good mechanic-type friend of mine had a stuck 216 early chevy 6. he wanted to put a supercharger on side of it. he was quite talented and could make all the patterns and pour the alum hisself. :) so before he made the castings he had to free it up. so he pulled the plugs and since it was parked on a hill, he put it in gear after putting some stove oil in each cylinder. he tied it to a tree and then let it sit with a load on the stuck pistons. he would rock it back n forth... over several weeks. he would set blocks at rear about 3" away... and soon the pistons moved a bit. he kept at it and over some time, he eventually freed up all 6 holes, installed the 3-71 Jimmy kit he built and off he went. but he was the kind of guy who could install valve guides in integral cast cylinder head/block antique engines. and build upside down tooling to cut the valve seats... wow~

so have u tired to put a load on the pistons and let gravity help u? a concrete block roped to pull starter locked to turn crank could help.

no doubt the best advice is to take it apart and clean it up and be sure its bearings free etc. but with some patience, etc, u may be able to free it up to run once u tune it, too.

well, let us know what u do, do?

regards

lakester :cool:
 

Silvertip

Supreme Mariner
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Sep 22, 2003
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28,758
Re: 1957 18hp Johnson seized

Be very careful with a wrench on the flywheel. Too much force can break the ring lands or the rings themselves. The trick is to rock the flywheel gently with a wrench. If it doesn't move at all, lub and wait. Try again in a week. Once the flywheel move the smallest amount, you will make headway quickly. Rotate the flywheel back and forth only within its limits of travel. Lub and wait. Eventually you will get it to rotate fully but patience is crucial. Then the question about bearings and bearing journals and cylinder wall damage enters the picture as mentioned earlier. You have two choices. Use twice as much oil in the fuel mixture during initial tank or two of fuel. If the engine continues to perform you could gradually cut back to normal mixes. Or, you can disassemble the engine and check things. Which way you go depends on how much of a gambler or risk taker you are. If you are unlucky and chose the first option you have a destroyed engine. Option 2 prevents that, but depending on what you find determines how much the repair will cost.
 
D

DJ

Guest
Re: 1957 18hp Johnson seized

have you drop the lower unit to see if the power head is siezed or is the lower unit siezed. if the lower is siezed the powerhead will not turn. your powerhead may be fine.

Agreed. Check the L/U.

For the price of a manual and some parts you can have a nice little engine. A great project for you and the 13 year old. He'll have a lot more respect for it if he rebuilt it.
 

yam350yfm

Petty Officer 3rd Class
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Dec 26, 2007
Messages
79
Re: 1957 18hp Johnson seized

Lots of great advice, thank you all.

Last night we went out and laid the motor down, pulled the plugs and filled the cylinders with PB Blaster again. This has been done off and on since Thanksgiving, so it has had a good 30 days of PB Blaster in the cylinders. It pulled through once, then it seized in where I believe is the same place it was originally seized, back to square one. I do have a Seloc manual on order for it and will probably pull it apart just to be safe. I really don't want to have an unreliable motor. So far all I have in the motor is the cost of a manual and a can of PB Blaster.

The previous owner did provide me some information that the motor may have gotten wet. He had the boat tied to his dock and was out of town during a major storm. When he came back the boat was filled with water. The power head was out of the water, but he is not sure if it was ever under water or how wet that might have gotten. He never ran it after that.
 

samo_ott

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Jun 18, 2006
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5,125
Re: 1957 18hp Johnson seized

If water might have gotten inside, I'd pull it apart. The crank and or rods are probabaly rusted then as well as the rings...
 

yam350yfm

Petty Officer 3rd Class
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Dec 26, 2007
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Re: 1957 18hp Johnson seized

I agree, looks like it is best to take it apart. One problem I am having is parts availability. Looks like dealers in my area do not have parts catalogs that go back that far. If I have part numbers they can get parts, but I have to provide the part numbers. Do you know anyplace this information is available online?
 

HighTrim

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Jun 21, 2007
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Re: 1957 18hp Johnson seized

check laingsoutboards.com for parts.
 

samo_ott

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Re: 1957 18hp Johnson seized

The parts manuals for specific engines appear regularly on ebay for not too much loot.
 

bikemike

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Feb 13, 2008
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Re: 1957 18hp Johnson seized

I bought a 1958 Seahorse 18 of a marina for $50.00 The guy lifted it up by the cord and said it's stuck. I took it home and having some experience with this problem in the past. I removed the plugs and poured diesel oil in. With the recoil removed I took a box end wrench and after soaking it for a week or so apply the wrench to the wheel nut and apply very little pressure to the left and to the right. This just flexes the rings a very tiny amount as not to break tehm. Keep doing this on a daily basis and the diesel will desolve the rust.
So anyway once it was turning freely, I put on the boat and with about 5 pulls she fired up. I use this motor all the time and you can't beat them.
Storing them is easy, burn the gas out of the carb and them fog them up really good. $50.00 CDN I couldn't beleive it!
 

samo_ott

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Re: 1957 18hp Johnson seized

That's a good luck story :) They don't all end up that way:) And yes, the 18's are great engines.
 

jay_merrill

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Dec 5, 2007
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5,653
Re: 1957 18hp Johnson seized

All of this fooling with the powerhead is too much work for me. I would invest the time in pulling the powerhead, going through the rest of the motor and slapping another, usable powerhead on it.
 
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