2000 - Johnson 50 HP Issues

My dad has my grandpaws boat. It is an aluminum haul with a 2000 Johnson 50HP (J50PLSSM). It has given us problems always and I decided to try and work on it since my dad doesn't have time. Believe it or not, the boat has sat for at least 6 years and it started on the first crank once I primed it. I was kinda amazed, but the issue we always had is still occurring. It will run fine for 5 minutes... then turn off. No excessive smell of gas besides your normal gas/oil mix burning.

Back before it sat, we had it worked on by 3 different mechanics. None got it working long. I believe the last guy had it working good at his shop. We took it fishing and didn't make it an hour before it started acting up. That's the last time I remember using it.

So, I kinda looked around. Made sure the hoses were fine and they were. Spark plugs look clean. So I primed it again and turned it on. Took a few tries, but it ran. When it started to die off, I pressed the throttle and it ran fine for 30-45 seconds then wanted to die again. I kept pressing the throttle and the issue would be temporarily resolved. Obviously this isn't a viable solution.

Anyone have an idea? Wouldn't those mechanics have said it was the fuel pump when we brought it in if that was it? It's a pretty expensive part LOL. They could have made a pretty penny on it.

 

Im no out-board motor expert but it sure does sound like a fuel problem...how bout cleaning the carbs and fuel lines going to it...I would think the fuel lines would have filters on the ends of it...maybe their clogged?

Are you using old fuel?

Is your gas tank metal or plastic? There Might be rust at the bottom if metal, that's why it'll run for a bit then suck up some rust and clogg it?

Is their any fuel adjustments on the carb? Play with that a little to see if it helps

 

its a johnson..problem solved...

in all honesty tho..it kinda sounds like the fuel pump may be on its way out. the reason i say this is because when you rev it, it sparks up a bit and runs but at idle its not getting enough push.

no expert here

and as for mechanics, depending on where you take it, believe it or not there are still some out there who want to help by starting with cheaper fixes first.

secondly. what type of gas are you running? pure gas or ethynol additives? the reason i say this is because after running regular gas in our boat before the bullshit ethynol came out deposits start to form in your tank. once you start puttin that shit in there it breaks down all the gunk and starts shoving it thru the motor.

i can go into more detail if you would like

 

The gas I am using now is ethanol free. I added a little bit of Seafoam. I cannot speak on my grandfathers behalf on what he put in there.

I will try changing the in line fuel filter then moving on.

 

have u checked to see if theres a hole in ur gas tank hose? sounds like it isnt staying primed also.....buy a new hose and see if that helps. thats worked for me before

 

do these engines have jets? if they are carborated they do, so i would clean the main and pilot jet as well as the whole carb.

 

More info please

is it a VRO system, how many reeds, what generation of fuel delivery. If it is carb. how many are on it?

Actually a model number or serial will work

 

J50PLSSM