'96 Johnson 175 fuel leak issue

[kitebuz]

I'm doing some work on our 1985 Mako 25 w/ twin 1996 OMC 175's. Both motors have been a bit hard starting & smoking more than normal. I figured out the starboard motor was leaking fuel where someone used a zip tie on the fuel line vs a hose clamp. Fuel would squirt out w/ each pump of the primer bulb...

I was hoping it was the same issue w/ the port engine, but no such luck. This one has been even harder to start & smokes more (like de-carb kind of smoking) during warm up. Oil will drip from the carbs if left unused for a few days. I finally got it started the other day, and noticed a fuel leak coming from fuel shut-off lever (red lever in pic). I don't have our the shop manual handy this week, so thought I would check here.

I can get fuel dripping around the lever - especially w/ a couple pumps of the primer bulb. I looked back when trying to start the engine at one point after priming the bulb, and actually saw a stream of fuel squirt out of it about 12". Is there a gasket to replace in this unit, or should I just replace the whole thing? Would a fuel leak here cause it to run rich? Like I said, it seems to be way over-oiling with the smoke, and oil seems to be leaking out into the carbs when in storage.

Thanks for any advice.

 

[racerone]

Re: '96 Johnson 175 fuel leak issue

The red lever is not a " shut off device " at all.---That unit is an electric valve / primer used to start the motor.--It operates when key is pushed in during cranking.---The red lever is used for manual operation of said device.----The leak at the red lever is due to a bad o-ring or the gasket.---Simple fix is to remove the 4 screws there .--Careful as the wee nipples like to break off , but even that part is available for repair.---The leak also may be inward when motor is running and that would lead to extra smoke / fuel usage.

 

[Chris1956]

Re: '96 Johnson 175 fuel leak issue

Kite, To add to what Racer has said, if you are using the OMS oil injection on those motors, any air leak into the gasoline line will cause more oil to be injected, causing more smoke. I had the main strainer leaking air, on my motor one time. The air was so blue with smoke, the mosquitos were dropping like flies. You could see a smoke trail on the ocean, marking my course.

 

[kitebuz]

Re: '96 Johnson 175 fuel leak issue

Great info - thanks. I knew I risked mis-labeling things w/out the manual, but I wanted to start figuring this out. I will order up the gaskets & O-rings and have at it.

Chris - the oil injection is still hooked up, although I was 1 step away from disconnecting and going pre-mix due to this issue. I still might, but I would rather fix the problem first. I am actually really glad to hear you say you've seen the same thing. I think we had a couple people at the docks nearly call the fire department it smoked so bad on start-up. I know I've got a leak at the primer valve now, and pretty sure it could suck air in a # of locations where they used darn zip ties on the fuel line. I'm going to fix the primer leak, and back track to the fuel tanks and replace all zip ties, and possibly run new fuel line.

On another issue, I don't know what this white cap is that is wired to a plug, but I was able to move it some side to side. Is it supposed to be tight or loose (& what is it)?

 

[racerone]

Re: '96 Johnson 175 fuel leak issue

The white bits are a fuel filter held in place by that round plastic nut.-Was there a hose attached to that nipple ?

 

[kitebuz]

Re: '96 Johnson 175 fuel leak issue

The white bits are a fuel filter held in place by that round plastic nut.-Was there a hose attached to that nipple ?

There was a hose attached, but I am talking about the plastic part with the two wires (black & white?) coming out of it below the filter.

 

[Chris1956]

Re: '96 Johnson 175 fuel leak issue

Kite, That motor has a vacuum switch installed into the gasoline side of the fuel system to warn if you have a fuel restriction. The item you refer to is the vacuum switch, and if it leaks, could be letting lots of air into the gasoline side of the fuel system causing the smoke. It should disconnect to replace. It also has an oring seal which could be bad.

 

[kitebuz]

Re: '96 Johnson 175 fuel leak issue

Kite, That motor has a vacuum switch installed into the gasoline side of the fuel system to warn if you have a fuel restriction. The item you refer to is the vacuum switch, and if it leaks, could be letting lots of air into the gasoline side of the fuel system causing the smoke. It should disconnect to replace. It also has an oring seal which could be bad.

I didn't see any leaking around it. I just wasn't sure what it was, and thought it was strange that it was not more securely attached to the motor. The obvious leak was at the primer valve, but I will keep looking for others.

 

[dazk14]

Re: '96 Johnson 175 fuel leak issue

The correct BRP zip tie is what is used on those and they work quite well.

 

[kitebuz]

Re: '96 Johnson 175 fuel leak issue

There are some ties that look fine, but I am talking about regular zip ties used for the fuel line that were doing nothing - & fuel was leaking out.

 

[boobie]

Re: '96 Johnson 175 fuel leak issue

If it's the zip tie designed for fuel line, make sure they are good and tight. They make a special gun to tighten them.

 

[dazk14]

Re: '96 Johnson 175 fuel leak issue

There are some ties that look fine, but I am talking about regular zip ties used for the fuel line that were doing nothing - & fuel was leaking out.

Fuel leaking out is obviously a problem. The brp's look the same, except they have very small added "ear" to better ensure a 360deg seal.