1962 Johnson Seahorse 28 hp won't run when warm

[Bogeskov331]

Hi

I'm from Denmark, so please excuse any gramma or nonsense

I have found this old motor and thought it would be a perfect fit for my vintage dinghy.

I have cleaned the carb, but i'm not sure how to set the jets. I have tried the settings from the FAQ article about how to adjust your carbs.

I have checked the ignition parts and all looks good. It seems to have good spark on both plugs, when it starts.

My problem is, when i try to start it, with choke and the jets at 1 and 1½ as written in the FAQ, it starts and runs for about 30 seconds or perhaps a minut, then it stall's and will not even cough before the engine has cooled for 10-15 minuts. Then I can start all over again.

It has run for longer durations, and I have checked the impeller, it looks fine and there is a small spray from the exhaust when it runs.

Does anyone know how to set the jets for this specific model to make it run for more than a minut.

please help.

If you have any good links for parts for this specific motor please post

[kfa4303]

HI Bogsekov331. Welcome to iboats. The symptoms you're describing are typical of failing ignition components. Have you removed the flywheel to check the condition of the points, condensers, coils? The points need to be clean, free of corrosion and gaped to .020 inches (not sure what that would be in metric?). How did you clean the carb? Did you disassemble it and replace all of the gaskets? If not I would order a carb rebuild kit. Without the carb being properly cleaned, the needles adjustments you made will make little if any difference. The good news is that all of these parts are readily available and you can get them right here at iboats. A tune up kit with points and condensers is about $20 (US) and a carb rebuild kit is about $25 (US). Here are some helpful links and pictures. They may not be for your specefic model, but all of the same principles apply. That's one of the best part about these older OMC (Johnson, Evinrude, Gale) motors. Once you can fix one of them, you can fix virtually all of them. Give these links a read and let us know what you find.

http://forums.iboats.com/engine-frequently-asked-questions-faq/awakening-sleeping-outboard-boatbuoy-158086.html
http://www.duckworksmagazine.com/07/...max/index1.htm
http://www.outboard-boat-motor-repai...%20Tune-up.htm
http://www.outboard-boat-motor-repai...%20Tune-UP.htm
http://www.marineengine.com/parts/vi...7898600001.htm
http://forums.iboats.com/engine-frequently-asked-questions-faq/carb-needle-adjustments-asorted-carb-variations-joe-reeves-167352.html
http://www.iboats.com/mall/partfinde...****=863458967
http://www.iboats.com/mall/partfinde...****=863458967



Lightwin-new-magnedo-ignition-system-PIC.jpgLightwin-new-magnedo-ignition-system-PIC.jpg

[bouttime007]

Welcome aboard Bogs!

How long was this motor sitting before you started working on it?

[Bogeskov331]

We had it running 5 or 7 years ago, but it was never runnning perfectly.

We bought it a couple of years before that, at that time it was completly stuck, but we got it going, and had i out af couple of times.

[Bogeskov331]

I have had the flywheel of and checked the pointers and condenser it all looked fine, no corrosion at all.
I didn't mesure the gap, just that they opened about the same.


The Ignitioncoils is a different story thou, the rubber was cracked
I have a 18 hp of similar age and it has the same ignition assembly. These coils was sadly also cracked.
I took the best looking coils and filled the cracks with hot glue, just as a temporary fix.
Is there any way I can test the coils to see if they are the problem?

The carb I took completly appart and cleaned it with WD40, a piece of cloth and compressed air.
It looked fine, no visible cracks to the gaskets, the jets didn't look damaged and the floater was a plastic and the valve closed nicely.

So I assembled it again.

I have checked the ignition by removing the plugs so i could turn the engine with my power drill. Then fit the plugs to the caps and hold them against the block and see the sparks fly.

The top cylinder seems a bit more stabile than the lower cylinder, but i should do for a testrun, I should think.

Previously I couldn't find any dealers of spareparts for these vintage engines so I had to work with what I had.

[kfa4303]

Sounds like you have bad coils Bogeskov331. The original coils that came with these motors were famous for going bad. They've usually been replaced by previous owners over the years, but it sounds like you may need to change them yourself. Not to worry. It's any easy job, and the new, replacement coils are much more reliable and shouldn't be a problem again. You can get them right here at iboats too. Because you're going to replace the coils, you should also replace the spark plug wires. They simply twist on to the posts on the underside of the coils. Be sure you use 7mm copper core wires (stainless steel core is ok too). Modern, graphite, automotive wire will not work. You can get the wire here too. Check out these links and the ones I posted earlier for instructions on how to install the new coils, and let us know if you have any more problems.

http://www.iboats.com/mall/partfinde...****=841128706 (you'll need 2 of these)

http://www.iboats.com/Boat-Motor-Spa...view_id.172285

[Bogeskov331]

Is it a coincidence that you chose the Sierra product?

because there is only one available and as you said I need 2.

Should a prefer sierra from mallory or CDI?

[Bogeskov331]

I was thinking of doing a compression test, but what numbers should I aim for?

Just to see if it is worth the effort or if I should start looking for another motor.

[F_R]

Don't do anything till you have replaced those cracked coils. That is why it won't run. Mallory, or other are just fine. I would think they should be available there in Denmark. In fact some of our best coils are imported from Germany. Have you gone to the BRP website and done a search for Evinrude dealers in Denmark? EDIT: I just did, and Denmark isn't listed, but Germany and Sweden are.

[kfa4303]

agreed. you'll need two of the coils I provided in the previous link. you should be able to order as many as you need from iboats or the BRP website as F_R mentioned. Sierra is a very popular brand name for Johnson/Evinrude replacement parts here in the states. I've always been very satisfied with their products. Mallory, CDI and most other brands are fine too.
As far as the compression is concerned, anything above 70 psi per cylinder should be good enough. Just as importantly, want the compression within each cylinder to be within 10% of each other. If there is a drastic difference between the two cylinders, you may have a blown head gasket. It's a fairly inexpensive and simple job to fix it, if need be. You may also want to spray a bit of lubricant (Deep Creep, Sea Foam, any petroleum based lube) into each cylinder prior to testing the compression to help free up the internals a bit. Compression numbers are generally lower in a cold engine than one that has had a chance to warm up when possible. You should also get higher compression numbers using an electric starter rather than by pulling it over by hand. Good luck!

[bouttime007]

I was thinking of doing a compression test, but what numbers should I aim for?

Just to see if it is worth the effort or if I should start looking for another motor.

As you know I have the exact same motor Bogs, and mine tested at 85-90 between the two cylinders and it has run extremely well. Its not a speed demon, but starts EVERY time.

[nwcove]

check compression before you spend money on anything else, you did say it was seized.