Old Johnson 4HP wont run on carb fuel

[fishon71]

I have an old 1980's Johnson 4 HP motor that will not run unless I spry starting fluid in carb.

Fuel pump pumps fuel okay and fills bowl.
Carb has been dis-assembled soaked, blown and cleaned.
Just seems like fuel will not leave bowl and get into intake.
If I give it a little squirt of starting fluid she starts right up.

Any ideas?

 

[tmcalavy]

Re: Old Johnson 4HP wont run on carb fuel

Old gas? Get a can of Sea Foam from an auto parts store, mix according to directions with some fresh gas, get it started and run it. Should help clear out any lingering crud in the carb and the entire fuel system. Could also be a bad or fouled plug, or weak spark.

 

[fishon71]

Re: Old Johnson 4HP wont run on carb fuel

I'm using fresh gas and carb & fuel system is spotless inside best I can see after soaking in carb cleaning solution and blowing out with compressed air. It really was not too dirty before I caleaned it.

Also I have new spark plug with strong spark. She screams with starting fluid. (I know this is bad to do!) Just does not pick up gas from carb for some reason. I suppose there must be something blocked some where.

I will tear it down again

 

[F_R]

Re: Old Johnson 4HP wont run on carb fuel

Without a model number we don't know what motor you have. But are you SURE the high speed orfice plug is clean? On most it is in the very bottom of the carb bowl, deep in the hole behind the hex plug. It has a tiny hole in it that must be absolutely, positively squeeky CLEAN. Anything less will give the results you describe.

 

[fishon71]

Re: Old Johnson 4HP wont run on carb fuel

Seems to be clean. I even looked at it with a magnifying glass under a bright light - shiney clean.

I'm lost with this one.

 

[tashasdaddy]

Re: Old Johnson 4HP wont run on carb fuel

you said you know starer fluid, is bad, it's the 2 stroles worst enemy, and an easy way to burn a hole in the piston. use some of your premixed gas. and a spray bottle. have you check the compression. may not be strong enough to pull fuel in. the fuel pump, pumps to the carb, the piston pull the gas in from there. and a low compression engine will fire on the started fluid.

 

[Scaaty]

Re: Old Johnson 4HP wont run on carb fuel

Does it hard start then STAY running? If so raise the float fuel level...