1995 Johnson 15hp

[Against Her Wishes]

Hi,

I've got a 95 Johnson 15hp (J15FREOC). I got it about 2 months ago from my brother who had it since 2007... without giving it any annual maintenance. The fuel line was leaking so i replaced the line & bulb & also replaced the spark plug. I took it out and ran it for about 2 hours straight then it cut off, thankfully it was when I was already back at the ramp. I can get it to crank & run for about 30-40 seconds as long as I spray some starter fluid in the air intake & keep pumping the ball, but it eventually just shuts off again.

Can someone help me figure out the problem? I was gonna install a fuel/water separator & also try to tinker with the fuel pump to make sure the filter isn't clogged.

 

[Daviet]

Re: 1995 Johnson 15hp

First off, no not use starting fluid, it has no lube in it. Use fuel mixture in a squirt bottle.
If the primer bulb pumps up firm and it will start by squirting fuel into the carb it sounds like you have a needle and seat problem, not allowing fuel into the carb. Sounds like it is time to overhaul the carb.

 

[Against Her Wishes]

Re: 1995 Johnson 15hp

Thanks for your quick reply! When you say I should be using a "fuel mixture" instead... what do you mean? How hard should the bulb get? I can keep pumping it & it doesn't seem to get hard enough to where I should stop pumping...
Also, & keep in mind this is my first boat so I am VERY green on everything...
Should I ever close the vent on the gas tank? I have a 12gal tank & one day I left about 5gal of gas in it & left the vent closed & over a couple of days all of the gas leaked out through the connector where the fuel line hooks up to the tank. I could see bubbles coming out of the connector. Does this mean there could be air getting into the fuel line?

Thanks for you help!

 

[Daviet]

Re: 1995 Johnson 15hp

Fuel mixture = 50:1 gas/oil mixture, the stuff in your gas tank.
If you close your vent on a hot day the pressure can build up in your tank and it will escape any wat it can. The leaking at the connector, if it's an omc type, is probably a defective o-ring in the connector. Could cause an air leak, you can replace them.

 

[Against Her Wishes]

Re: 1995 Johnson 15hp

It's a 4-stroke motor so I don't use a gas/oil mixture in the tank. My brother told me only 2-strokes you need to use a mixture on... he was using just high octane & said I should use that.
Could the air leak cause the motor to do what it has been doing or do you still think the the carb needs "overhauling"... & by that do you mean rebuild or cleaned?

 

[Daviet]

Re: 1995 Johnson 15hp

Sorry, i am so used to working on 2 strokes that I forget there is anything else.
I think you still have a carb problem, if you have to choke it or spray fuel into the carb to keep it running you need to overhaul the carb. Take it apart, clean it completely and install a new carb kit.
I am sure some one with 4 stroke experience will come along and offer additional advice.

 

[Against Her Wishes]

Re: 1995 Johnson 15hp

Okay, well thanks for all your help Daviet!