1955 Johnson 3hp only runs on full choke

Excellent site, this is fantastic for searching for info! Kudos to you all! Like you've all seen before, I rescued a 1955 Johnson JW-11 Seahorse 3hp, in good shape, had been sitting for 10+ years without running, gas in it. Totally disassembled carb and cleaned out every nook and cranny. Fuel tank spotless, as is fuel line and shutoff valve. Gaskets looked good actually, didn't put in a carb kit (yet). Lower unit oil looked good, she cranked up on pull 3! BUT, now will ONLY run with full choke. Fuel filler cap vent is open, so don't think that's the culprit. When running with full choke, and then when it's closed/off, the motor will surge and then die. Any ideas on what could be issue, what I missed, etc??? Any and all info GREATLY appreciated! Thanks!

Re: 1955 Johnson 3hp only runs on full choke

It's a fuel supply problem. Hate to say it but you missed something in the carb. I'd get a kit and put it on... They're real cheap and easily available. Personally, I would not waste the labour to take a carb apart if I wasn't putting a kit in it for the $20 or so... It's just not worth the time to re and re it again.

Did you soak the carb or use carb cleaner when apart?

Btw, did you check the coils? Usually the old ones are toast unless they have been replaced.

And welcome to iBoats

Re: 1955 Johnson 3hp only runs on full choke

Sitting for 10 years with gas in it...pull the carb again, take it apart and let the body soak four a couple of days in carb cleaner, then blow it out and reassemble. It's either crudded up somewhere inside or maybe the float is not floating, you can let the float dry out and then re-seal it with shellac, fuel proof dope, superglue or two-part epoxy. Definitely check under the flywheel...coils/points/condensors/plug wires, etc., it's due for a tune up.

Re: 1955 Johnson 3hp only runs on full choke

Welcome to the forum!!

Re: 1955 Johnson 3hp only runs on full choke

One other thing. There's a metal mesh grate that goes between the air horn and the carb mouth. That's gotta be there for proper running. It's fairly coarse mesh and actually acts as a bit of a choke to richen the fuel load.
- Scott

Re: 1955 Johnson 3hp only runs on full choke

How about the filter in the gas tank? Does it have the sintered balls type filter? Those things are virtually impossible to clean and are meant to simply be replaced. Remove the fuel line to check for healthy flow from the tank.

Re: 1955 Johnson 3hp only runs on full choke

amzoil powerfoam unclogged my fuel screen... You're probably leaking air in through the cracked jet packing. I replace w/o-rings if I don't need the whole kit. Also, make sure the washer gasket between the carb halves is sealing. If it's a cracked cork one, get a carb kit. The 'metal intake screen' that a responder spoke of isn't mandatory to get her to run well, but put it on if you have it. g'luck,kirby

Re: 1955 Johnson 3hp only runs on full choke

Great little motors! Try this web sight (one of the pros here gave me this) they have a complete kit for that motor, carb kit, points, coils, water pump plus complete easy to understand instructions. I put one in my 3 hp JW-17 and it runs like a new motor! http://www.maxrules.com/fixtuneitup.html

Re: 1955 Johnson 3hp only runs on full choke

there is a little brass tube that has your gas shut off on it. It looks like a regular nedle valve but it has a screen in it and often actually very often gets clogged. pull the valve out and look at it. might be that simple

Re: 1955 Johnson 3hp only runs on full choke

I recently restored a JW-11 1955 model johnson 3 horse. I had similar problems with the motor running. It turned out that the fuel filter, which is located inside tank above the shut-off valve, was clogged. This type of filter is a piece of brass that is porous on the top end. I removed that filter and installed a new fuel line with a filter inline. For future reference, can anyone say if it is possible to repair one of those brass filters.