20 hp Johnson Fuel Line Question

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RutStrut

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A couple of questions for those that may have experience, the manual suggest 5/16, but I installed a 3/8. Having problem on start up and not getting enough fuel, I dont want to spend the money and replace with a 5/16 if not needed. Also wondering if an in-line fuel filter would be a good idea? Wanted to add that this is the factory jet model # J25JRSS. Anyone have any info on this motor I would appreciate it. I inherited it from a family member that only used it 4 times, total of 12 hours. I have replaced some of the wires that were chewed and put new plugs in.
 
Pump your primer ball to over ride the fuel pump.Make sure impeller is good if its been sitting a long time.I don't think your fuel line is the issue.
 
3/8" is larger than 5/16". If it is not getting fuel with the 3/8" line, the line is not your problem. As mentioned earlier, pump your primer bulb. If it is still not getting fuel, check your carb. Check for dirty or stuck needle valves or a hung up float. A trick I have learned on these small two cycle engines is to take a spray bottle and spray some of your fuel/oil mix into the carb to see if it runs on that. Most of the engines I work on either have no fire at the plug or no fuel going into the cylinder.
 
KMixson said:
A trick I have learned on these small two cycle engines is to take a spray bottle and spray some of your fuel/oil mix into the carb to see if it runs on that.

Good advice. I carry a small squirt bottle (from my GF's hair color stuff) on both boats. It came in handy a few times during no start conditions. I just put some premixed gas in it from my spare one gallon jug that I always carry and squirt directly into the carb. This got me home a few times.
 
Another tip I recently read about is to try and keep the primer bulb pointed skyward when pumping it so the check valve inside doesn't interfere.
 
Thanks for all the suggestions and tips, I think I have narrowed it down to some junk in the old plastic tank. When I emptied the old gas it seemed clean and not discolored, so I filled in with prem gas, oil and a can of seafoam. One time when the motor quit and the squeeze ball deflated, I disconnected the line from the tank and noticed some crude in the holes of the adapter. So my plan this weekend is to funnel the gas out (funnel with a screen) clean the tank by adding some gas and washers, gravel, etc and try her again.
 
I'm sure this happens to the best of us, but double-check the fuel tank VENT.
 
HA about that fuel tank vent...

I just bout a 68' Evinrude 18 HP and the first time I took it out it ran fine for a few minutes and then died out. It started right up again, run well and then... it would die out again. After taking it out again tonight and trying a few things I think we narrowed it down to the vent on the fuel can. When I took the lid off I heard a hissing sound likek air rushing in.

Is there an easy fix for this like new fuel cap? Is there a vent I can buy to install? Can I drill a small pin hole in the top to allow air to get in?
 
atuck593 said:
HA about that fuel tank vent...

I just bout a 68' Evinrude 18 HP and the first time I took it out it ran fine for a few minutes and then died out. It started right up again, run well and then... it would die out again. After taking it out again tonight and trying a few things I think we narrowed it down to the vent on the fuel can. When I took the lid off I heard a hissing sound likek air rushing in.

Is there an easy fix for this like new fuel cap? Is there a vent I can buy to install? Can I drill a small pin hole in the top to allow air to get in?

Almost the exact same situation on my 20hp Johnson that I'm giving away. I actually ran it with the fuel cap almost falling off and same situation of the intermittent stopping and eventually no start condition. Good luck.
 

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