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2000 Johnson 50 hp J50PLSSM (No start, cranks like a champ) possibly becoming a boat anchor

S

Sz90pw

New member
Hello All, thanks for admitting me as a new member:

I have a 2000 50 hp johnson model J50plssm:

This motor has been nothing but trouble since taking ownership this year:

Symptoms include the following:
  1. Will not start unless starting fluid is sprayed, When it is, only runs a couple of seconds. Primer bulb does firm up when squeezed.
  2. If and when it does decide to fire, when the trottle using the remote throttle is applied, there is a delay for the carbs to recognize and then they rev up erractically.

Here is what I have done so far:

  1. Changed the plugs
  2. check continuity on the coil wires.
  3. checked the continuity on the coil pack
  4. replaced the CDI powerpack
  5. checked continuity of primer solenoid
  6. cleaned carbs
  7. replaced fuel diaphragms in the VRO unit
  8. replaced gas line from tank to engine along with primer bulb
  9. replaced all fuel lines internal to the engine
  10. replaced fuel filter
  11. checked compression on both cylinders (each read 140 psi)
  12. I adjusted the timing per the service manual for the crank spark lever to 2.5 inches and adjust throttle linkage to the correct start points.

Still can't get it to run correctly or at all. I am at my wits end. Any and all advice is appreciated.
 
One step at a time.-----It sounds like the primer VALVE is not working .----Pull wee hose off the top carburetor.-----Crank engine while pushing key in.----Does fuel pulse out of the wee hose ?---When you had carburetors apart for cleaning did you find any dirt / varnish in the bottom of the carburetor bowls ?
 
Last edited:
Racerone,
Thanks for the quick response.. When I took the carbs apart, the float bowl area and the surrounding components looked fantastic. Looked very clean and no signs of varnish build up.
I am not sure about the wee hose. I assume those are the two hoses that come from the primer solenoid? I will take a look at them tonight. However, when I did push the ignition key primer, the sound was different, so it may be coming out, but I will visually confirm tonight.

The other thing that I will do.. Empty the entire fuel system and start with new gas and new plugs, I hope to try that tonight.

Any other tips or suggestions are greatly appreciated.
 
If you are willing to trouble shoot based on many years of experience , some here can help you navigate and find what is wrong.----If you want to replace parts and do things based on what your friends / neighbor suggested then we can not help.
 
racerone said:
If you are willing to trouble shoot based on many years of experience , some here can help you navigate and find what is wrong.----If you want to replace parts and do things based on what your friends / neighbor suggested then we can not help.
Click to expand...

Thanks for the advice.
Finally got back down to it and pulled the wee lines off the top of the carbs, while cranking the engine and pushing the key for choke, no gas coming from either of those lines. The fuel lines were blown out but still no gas. Multimeter shown 4.8 ohms, but a bench test with a 12 volt battery on the wires should make the solenoid fire but it does not.could this be the problem for no cold start or any starting for that matter?
 
Dangar Studios has a video on how to check/test/overhaul the primer solenoid. It's on YouTube, and should be visible on this site as well in the videos section.
 
Thanks for the info!
what I have found out is that when the primer solenoid has 12 volts going to it, it will click to pull the plunger and release more gas into the system. The problem is when the power is removed, the plunger stays in a stuck position allowing excess fuel into the carbs flooding the plugs and losing spark. When the power is removed to inner springs of the solenoid should extend the plunger and seal off fuel. Has this ever happened to anyone?
 
In an experiment, I removed the primer from the boat, pinched off the fuel line and attempted to start it. No luck.
my spark is also noticeably weaker on the top plug than the bottom plug.
Any one have any ideas?
 
All,
I am in a conundrum now..
the engine will show signs of life while giving almost wide open throttle in neutral, it will fire up, rev high rpms and then slowly die out within 5 seconds I cannot keep it running, any ideas?
 
Boobie said:
Replace the primer or squirt some fuel in the carb throat to try and keep it running.
Click to expand...
Boobie,
thanks for the advice! The primer was replaced and is functioning, gas is squirting from the top carb line while cranking and key pushed in. Float bowls on carbs are full. Must be something in the carb?
 
Some will argue.----Spend no money.------Have your battery load tested.----Take starter apart for inspection and an ohm test on armature.----Inspect battery cables.-----Check flywheel key.-----Some simple trouble shooting needs to be done.-----Or hurry to a shop and they will quickly determine what is wrong here.
 
An update.. after breaking down and replacing carb inners, it runs for a short time until the “no oil” light comes on. The conditions are it will run in neutral on the first detent for about 3 mins until the “ no oil” light comes on. So close to success. Any thoughts? This engine does have the VRO system.
 
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