Runs, but not for long

[JET]

I have a 1968 Johnson 3 hp 2 cylinder outboard with new coils, plugs, condensors and a clean and shiny carb etc., as well as a new fuel tank. Plenty of fuel at the carb when not running. Motor will start, but must be held on the choke to keep going. Eventually dies after two or three minutes. Everything is gapped properly and initial setting on low and high speed mixture is one and one half turns out from fully closed. I have tried adjusting mixture as we go but it wont run long enough.<br /><br />Any suggestions?<br /><br />Thanks for any help

 

[sloopy]

Re: Runs, but not for long

LOCALLY for you, you need to clean the plugs, I had this problem to... I have no iea why the blugs get dirty when every thing else is new!!! put some new ones on and spray a hlf bottle of ether in a 6 gallon tanl full of gas, then mix this ether/gas with 16/1 oil. pour it into your the gas tank and run it (underoad) then keep doing this until, you are done with all that gas! note you can also just mix it in a 5 gallon can, I just like even numbers

 

[JET]

Re: Runs, but not for long

plugs are brand new and clean and give a good strong spark.

 

[rickdb1boat]

Re: Runs, but not for long

Jet, can't help but thinking it's still a Carb. problem. If I were you, I'd tear the Carb off again and make sure the float is set properly and clean it again real good. Blow it out with compressed air and try it again. Don't go mixing up all the VooDoo cures, cause if it won't run right, now, that's not gonna help cure the real problem. Did you use a rebuild kit on the Carb. or just clean it? Could be the needle seats are sticking or any number of things that a kit would take care of! Also, after it dies, pull the plugs. Are they wet?

 

[harrison20002]

Re: Runs, but not for long

Hi Jet; DON'T use any kind of Ether mixture. You'll wash all the oil off your cylinders and dry metal to metal will raise **** with them. Listen to Rick. Recheck your carb. rebuild, especially the needle valves and float level. One other thing, is the vent open on your fuel tank? Makes a guy feel stupid but we've all done it once or twice. Happy Boating & good luck with your OB. Hal

 

[harrison20002]

Re: Runs, but not for long

JET: Be sure and let us know what your problem was. This is a very common problem and will surely help someone else down the line. Happy Boating, Hal

 

[Brew]

Re: Runs, but not for long

If the rechecking the carb doesn't resolve anything, you might want to look at your fuel line. If you've got an air leak somewhere, that might starve the motor for fuel.<br /><br />Good Luck!

 

[JET]

Re: Runs, but not for long

Thanks to everyone for the help. This forum and a good manual can work wonders. The motor now runs well at idle, ticking over like a little clock. at full throttle it runs reasonably well. When throttling up from idle it has a tendancy to die if you go to fast. Sometimes it wont get to full throttle without dieing. Is this just a mixture control problem?