johnson 50 fuel starving issues

[bsilvester]

ok first let me introduce myself my name is brandon and im new to this forum, i deceided to start a new thread as it seams none quite match my problem and need help bad so here it goes
I have a johnson 50 hp 4 stroke efi low emmisions motor on my boat and the motor only has about 30 hours max on it. when i run it with muffs and a hose all if fine no issues. The motor starts and ideals awesome and will for an eternity, however when on the lake i start going and any throttle at all and after a few minutes it sputters and dies, it will restart almost imidiately and run the same amount of time, however when it starts to sputter i can reach back and pump the prime ball and it will continue to run fine. its been to two mechanics and has had the fuel tank pick up replaced, all fuel lines, filters, connections, o rings and the fuel pump replaced both inside the motor houseing and outside includeing the primer ball. now im lost
ANY ideas where to go from here or maybe someone who knows whats up thank you in advance and hope to meet everyone soon
Thank YOU

[Cofe]

Not too familiar with 4 stroke outboards, but it sounds like the carb float needle may be sticking.

What year is your motor? Any warranty?

[vandad]

Hi Brandon,
Start step by step:
Check whether Fuel is being pumped into the engine or not, but just looking at the fuel filter you can see whether it is being filled/emptied regularly or not. If not, then you either have a leak somewhere in your fuel line/ or even perhaps somewhere near the fuel filter/fuel pump. It may be worse and your fuel pump may be faulty.
The fact that you say you must pump the fuel using that prime ball is due to a leak somewhere BEFORE it reaches your carbs.

Also, remove the engine cover, start the engine, and manually open the throttle (engine accelerates) and see how long it can go before dying. Maybe, your carbs are flooded after a while, maybe you need a new floater in your carbs.

Also, make sure the air hose are connected and not blocked.


I had the same problem with my Evinrude 70hp. I just rebuilt the carbs and now it works fine.

[lmuss53]

It looks like you've been all through pumps, hoses and connections. Is the tank built in? Could it be a plugged vent? Try it on a portable tank and see if it gets better.

[bsilvester]

hey guys thank you bunches i learned picking the brain of an evenrude johnson mechanic that there are two fuel pumps on this one, one fills the bowl for the second to up the pressure for the injectors and i took it apart found float stuck 1/4open, and alot of crap in there. in the process of cleaning it and putting it back together. gonna take it out to the lake this weekend let you know if thats the fix.
THANK YOU

[bsilvester]

It looks like you've been all through pumps, hoses and connections. Is the tank built in? Could it be a plugged vent? Try it on a portable tank and see if it gets better.

ps the pic of your boat looks just like mine LOL