84 Johnson 115 fuel issue

AventuSD

Recruit
Joined
Apr 2, 2017
Messages
3
Hi guys, longtime lurker 1st post.


I have an 84 johnson 115 that was running great until water got in the tank courtesy of a disintegrating gasket on my fuel sending unit. After pumping out all the bad fuel I replaced the sender, sealed it up, refilled fresh gas with stabil 360, replaced my racor fuel water seperator and rebuilt and cleaned the carbs for good measure.

The engine started up and idled great. I headed towards the end of the no wake zone, hit the throttle and just as I was starting to plane off, it seemed fuel starved lost power and stalled out. I reprimed the system and the engine would idle and run slow all day but whenever I went to give it more than 50% throttle it kept losing power. I limped back to the dock and started researching what it could be.


I replaced my anti siphon valve and checked that my tank vent wasn't clogged. I checked all my fuel lines and replaced some of the older lines inside my outboard, upgrading to stainless clamps rather than plastic. I also checked and cleaned out the small fuel filter inside the outboard.

Tested it again, same result. Now I'm wondering about the fuel water seperator. I used to use a 30 micron but all west marine had was 10 micron so perhaps that is my issue? I was assured it shouldnt matter but just in case I purchased another 30 micron filter, cleaned out the filter housing ports with carb cleaner and compressed air and reinstalled all the fittings. I then properly filled the canister with new fuel before installing to ease priming and reduce air.

The boat ran great for about 15 minutes before bogging down again. AGAIN I limped back to the dock. It's definitely a fuel issue so I suspect the fuel pump. My setup is a mix tank with a diaphram fuel pump (438556). I used the rebuild kit and got the same results so I just ordered a new sierra pump thinking maybe my Springs were too worn or something.

I took it out on a test run and it stalled out just like previous times. As I'm messing with the engine and checking everything, I'm getting closer and closer to the rocks and Navy property. The motor wont fire now... great. Finally out of desperation I undo a few hose clamps and bypass the filter completely running my main tank line directly to the engine. The motor starts and runs 100% the rest of the day.


I took it Fishing today and all was perfect other than im not using my fuel water seperator.


My question is what else could I be missing here? My motor always ran great with the racor 30 micron previously. Now 2 brand new filters and a new fuel pump later, I can't get it to pull fuel through the filter.

Long post but thanks for reading!
 

AventuSD

Recruit
Joined
Apr 2, 2017
Messages
3
Anybody? Maybe there's still some water in my fuel and it clogs up the filters pretty quickly?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
Trouble shooting on a 1984 model starts with a compression test.----------Always the first thing to report.
 
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