Johnson Seahorse 18, no spark

[KRS]

Received this motor free, I'm thinking about getting it going.

I pulled the plugs, squirted in some Deep Creep and it turned over easily.

I attached the wires to the plugs and... no spark at the plugs.

I have no idea if I should dig deeper or see if someone wants it.

I also received a Sears <5 HP model, and it doesn't turn. Pulled the plug and I can see oil in the cylinder.... so I'm wondering if it's the pull-cord assembly.

Anyone?

Thank you.

 

[F_R]

Re: Johnson Seahorse 18, no spark

That's a classic. Too bad you are so far away or I would take it off your hands. You can bet the coils are shot. They always are unless they have already been replaced. They have new ones here at i-boats.

 

[58 Johnson]

Re: Johnson Seahorse 18, no spark

Cool motor... a 1958, my personal favourite! I have learned through a old motor dealer that 1958 was unique in that it was the only year that Johnson used script in its lettering! Lots of stuff on the ignition system in this forum if you scroll down some. Even another one on 58's. Other posts will give you ideas and links for FAQ's. Pop that flywheel and get looking. Parts are easily available and easy to replace with even a minimum amount of knowledge and background.

 

[58 Johnson]

Re: Johnson Seahorse 18, no spark

But... before you spend time under the flywheel, you might want to first check the compression to make sure your efforts aren't wasted...

 

[burroak]

Re: Johnson Seahorse 18, no spark

While you are at it, check the lower unit for fouled lubricant. If you have good compression and a sound lower unit, the coils points, condensers, high tension wires are as low as $60 on ebay "Buy it now". The carb kit is just under $20 and misc fluids and cleaners are another $15. For a $100, you'll have a sweet little motor.

To update the motor and not worry about a pressurized fuel tank, find a fuel pump and by-pass cover plate from a '60-'61 and a motor side single line fuel connector and convert it to a single fuel line and use 50:1 mix. A 1/8" pipe thread brass plug will seal the crankcase (that's where the pulse came from to keep the tank pressurized. By the time that is done, including new hoses, pump/cover plate, and plug you'll have another $55 in it.

You'll have a hard time finding a motor that good and serve you so well, for $160. Good luck

 

[KRS]

Re: Johnson Seahorse 18, no spark

I should send it to you burroak with $200 and I'll get it back all done 8)

I should do a compression check... so I need to purchase a compression gauge.

I'm just wondering if it would be that easy.... compression okay, new coils (two), a few new wires, a few new hoses, new impeller (if it has one like my alpha one), new gear oil, a conversion for the fuel pressure thing.... and I've got a good motor?

 

[58 Johnson]

Re: Johnson Seahorse 18, no spark

Yup... that easy. As a wise man told me not so long ago on iboats... it will probably outlast you. The two line (pressurized) tank will work fine but parts can be a hassle when needed (although that is rare) and fiddling with the primer button, occasional leaking from the tank gasket, etc. can be a pain. But perhaps you like the romance of the old days. There are easy to find original paint colours and decals now too if restoring interests you. The oldies turn plenty of heads at the marina. Bullet proof and simple motors!

 

[Chinewalker]

Re: Johnson Seahorse 18, no spark

DO NOT run that motor on 50:1 mix. Use a 24:1 mix. The oil does more than lubricate and is needed as much as a sealant and cushioning agent. Motors back then had much looser tolerances and need the extra oil...

Those old 18s are quite possibly one of the finest motors ever built. It was made in one form or another from the early 1950s to the late 1970s. Lightweight, good power, easy maintenance, good parts availability and all-around classic good-looks make it a winner!

- Scott

 

[tmcalavy]

Re: Johnson Seahorse 18, no spark

Check compression...both jugs should be above 95 and within 10% of each other. If it has compression, pull the plugs out and take the cowl and recoil off...like in your second photo. Look for an access plate on the top surface of the flywheel, you can open that plate turn the flywheel slowly and check condition of the coils, points, condensors. If the coils aren't cracked, no need to change them. If they are, you need to pull the flywheel, replace coils, clean and reset the point gap, put it back together and check for spark again. You should get a strong blue spark capable of jumping a 1/4 inch gap. Easiest way to check the water pump/impeller is put it in the water, on a boat or on the side of a barrel filled with water...you'll need a pressurized old-style fuel tank for this (check Ebay...usually less than $60). Start it up and watch for a good water discharge out of the hole about half way down the back of the leg. If no water shut it down and change the pump/impeller. Might want to do the lower unit seals at the same time if the LU shows signs of water intrusion. You can get a seal kit for about $25. Like the others said, it's one of the best Johnson's made or it wouldn't still be around and usable. I recently restored one, including paint and decals...wouldn't even consider selling or trading it. Most E-rude/Johnson dealers or a good marina/mechanic will be able to get the parts. It will cost more than a pressurized tank in good shape to convert it to a modern one-line tank...mine was done before I got it, but I've seen several since then that run just as well and reliably with the older two-line pressure tanks. The Evinrude cousin to your Johnson is the Fastwin...same motor, different paint color and top cowls. The guys on the Ask A Member board at www.aomci.org can provide the parts list/schematics for your Johnson...just ask. Don't see the recoil mechanism in your second photo...if it's missing you can find one for not much scratch...from a E-J source or the auction sites. Lucky pup...got it for free.

 

[burroak]

Re: Johnson Seahorse 18, no spark

DO NOT run that motor on 50:1 mix.


Why do you say that? This motor has needle bearings. Old wrenches will tell you that 50:1 is just fine. I'll refer you to Joe Reeves, who posts here some and much more on www.marineengine.com.

To KRS, yes it is that easy to do. I have just finished doing all of that to the identical twin of your motor. The info on converting to a single line cost me 14 months of asking, reading, and wheedling anyone who would stand still. The most common approach is to use an impulse pump, (snowmobile, ATV, go-kart,) and jury-rig it to the motor. The fuel pump and by pass cover plate method is the direct result of OMC engineering and is the most sanitary looking, especially if you match the powerhead paint. But they are the hardest to locate. If you are interested at all, check out boattownmike on ebay. He has a lot of that stuff.

 

[tmcalavy]

Re: Johnson Seahorse 18, no spark

I'm with Chinewalker...why risk that old gem to save a little oil? 24:1 is factory spec...your choice of course. There's a good outfit in Milwaukee that has the stock bypass cover...Engine, Blade & Prop (mods forgive the commercial reference, offered as info only).

 

[KRS]

Re: Johnson Seahorse 18, no spark

No one lives in Arizona to walk me through this 'eh?
:'(

 

[burroak]

Re: Johnson Seahorse 18, no spark

Get yourself a manual for the motor; it will walk you through the whole process. It's bare-bones basic parts replacement.

 

[KRS]

Re: Johnson Seahorse 18, no spark

Was just outbid on ebay for a Seloc manual.... someone sniped me!

I'll keep looking.

 

[KRS]

Re: Johnson Seahorse 18, no spark

I forgot to include:

FD-12

1693450

 

[burroak]

Re: Johnson Seahorse 18, no spark

PM me and I can help you out with the manual.

 

[KRS]

Re: Johnson Seahorse 18, no spark

Okay, update time.

I purchased a compression gauge, and checked both cylinders.

I pulled the plugs on both, screwed in the threaded end of the gauge, and hand rotated the flywheel with a round-bottom screwdriver (coil starter isn't working on this high-quality freebie). Checked each cylinder.

First off.... I have spark! While doing this both plugs were sparking !

Okay, both cylinders were 50 psi. Not sure if they coulda gone higher because it's hard to crank that flywheel like that.

So, if I'm getting spark and both cylinders match... granted they are significantly less than 90psi, what would you do next if this was your motor?

Thanks,

KRS

 

[Scaaty]

Re: Johnson Seahorse 18, no spark

New coils (don't care if ya are getting a spark now)...been through more FD 11's than I care to remember.......24 to 1 on oil or I will come and take it away from you..(yeah rollers on the big end, but the DAMN WRIST PINS ride on brass bushings..you will toast them if ya don't flip 24-1 at them)​

 

[tashasdaddy]

Re: Johnson Seahorse 18, no spark

pull the recoil off, there should be a notch on the fly wheel that will hold a knot of a pull rope. turn by hand, is not enough to get a good reading. tilt it so it is face down, remove the plugs, put some marvel mystery oil in the cylinders, let it sit overnight. then drain the oil. recheck the compression, using a pull rope. the recoil tang may just need a little oil to catch on the motor. this engine is worth pull time into. just sold a 1955 15hp that ran better than the new ones, in the process of getting a 58 35 hp running sweet. i just priced the parts for complete tune up, water pump kit,carb kit, float, points,cond. coils for, mine $136.75 at laingsoutboards.com. the cheapest i could find as an overall package. here's a pic of the under side of the recoil, if it's dirty the tang, may not move.

 

[tmcalavy]

Re: Johnson Seahorse 18, no spark

Definitely check compression with a rope as TD suggests. Do you have a fat blue spark or a yellow spark? If yellow, time to look under the flywheel and check coils, points, condensors and check the wire connections. If the old recoil is toast you can get one for not much scratch on the auction site, just keep watching. Keep it and run it and take care of it...if you do this your kids won't have to buy their first outboard.