Old Johnson Sea Horse

Chris · 05 July 2007, 21:04

Whilst clearing out my great uncles house after he passed away we found this old Johnson Sea Horse 1.5hp engine.

Apart froma couple of scuffs and scratches its in v/good condition and all the control operate smoothly it has plenty of compression and turns over like silk.

It will be perfect on the tender however does not have a recoil start and I dont have the pull cord. Anyone know where I can get one from?

Chris

Nos4r2 · 05 July 2007, 21:15

B&Q sell starter cord. Cut it to length and tie a knot in it.

It'll need an impeller after standing for a long time.

Chris · 08 July 2007, 20:49

OK I mixed some 50:1 and got hold of a starter cord, after a few pulls the engine started and ran quite smoothly I cant get it to idle consistenyl sometimes it lasts a few seconds before it starts to die and you have to rev it to keep going, sometimes it will then idle for 20-30 seconds quite well then suddenly stop. I am still using the old Champion J4J plug that was in it as it looked to be in good condition however could this be the problem?

What plug is the best to use in this engine?

What else should I be looking at?

There are low and high speed mixture knobs what is the procedure for setting these?

Finally there is no tell tale to check the water flow from the impellor however there are 4 small holes about half way up the leg through which exaust along with a small amount of water sprays out (enough to wet your finger if you hold it there for a couple of seconds) is this correct or should there be a stream of water?

Any other hints as to how to get this engine running well would be appreciated, it has been stored indoors and there was no petrol in the tank when I found it however thats not to say that he would have drained the carbs before last being used. I suspect it has been at least 15 years since it was last used.

Chris

Nos4r2 · 08 July 2007, 21:03

I think those run on 25:1 rather than 50:1.

Cutting out might be crank seals perished.

The impeller IS working but sounds worn or the waterways are a bit furred up. If it's cooling properly you can keep your hand on the cylinder head without it being painful while it's running.

Chris · 08 July 2007, 21:17

Nos the instructions on the tank say 50:1, I am using the same oil XD30 that I use in my main engine will that be ok?

Chris

Nos4r2 · 09 July 2007, 16:25

Yeah it'll be fine with xd100. Anything TCW3 will be a huge improvement on what it had put through it when it was made!

If it says 50:1 then use 50:1. They used 25:1 before a certain age, just not sure quite when. I know it was sometime in the 50's.

Chris · 09 July 2007, 16:40

I could not get it to start today so I pulled the carb apart and that was fine all the jets are clear, I also took the cylinder head off because the top of the piston looked like it was damaged however as it turned out it was fine. I also pulled the big end to get the piston out to check the rings and had the fun of fitting 30 needle bearings back into place (good old vaseline).

All looks very good inside so I reckon the fault is electrical. So Spark plug first then trouble shoot the magneto and ignition system.

Chris

Nos4r2 · 09 July 2007, 17:11

<slaps head> Of course....

It'll be the ignition coil/magneto thingy. It'll have a crack or cracks in and be rusty.

Seamark Nunn sell them. About £17 each.