Unusual problem on a 5.5hp Johnson 1960

[joesnuffy]

I have been working on a 1960 5.5hp Johnson. The motor runs great once I get it running. The problem I am having is when I first start it I pump up the fuel bulb and I can hear the carb filling up with fuel like on any other motor. If I choke the motor it won’t hit or start. If I disconnect the fuel fitting on the motor and set the speed to fast and pull it over like 7-10 times without choking it then it firers up and runs and once its warm it starts up first or second pull without choking it like most motors. I put a new style float in carb replacing the cork one but they both give me the same results. Not sure what to think I thought someone might have encountered this issue before. I can live with the issue but I was thinking of selling the motor so I wouldn’t want t sell it like that. Any help appreciated.

Joe

[Mumbles]

Sounds like the float valve is leaky, worn, or dirty, and the motor is flooding itself.

[joesnuffy]

Thanks Mumbles I will replace the valve I think I might have one on a parts motor and see if that does it before purchasing a new one. I did unscrew the brass fitting for it and made sure it had the plastic washer and made sure once I put it back in I made sure I tightened it snug. The needle looked to be o.k. but I did not pressure test it the bowl has to be on it for fuel to go into the carb. Is it possible to flip the carb upside down and try pumping fuel into it using the bulb?? to see if I can get fuel to go past needle?

[chris-p]

Or float height wrong.

[steveh]

My ’59 CD-16 5.5 had similar symptoms. I replaced the thermostat and cleaned the points. Fixed the issue.

[joesnuffy]

Chris,
I think the float level is correct. When I flip the carb upside down the float is level in the closed position. When I put the new float on it also was level in the closed position. I did adjust the new float to drop down making sure it did not get hung when all the way down.

Steve,
The motor has the thermostat and when the motor is running it is runs at a good temp not to hot and it also warms up quickly. I also have electronic modules in the motor and it runs awesome once its running.

What I do know is when the motor is running no fuel comes out of carb. When the motor is running if I pump the bulb it will make the motor slow down until it burns some fuel then it goes back to running normal. When the motor is cold if I pump the fuel bulb until carb is full then pull the rope the spark plugs get flooded with fuel. I think it may be a leaky needle valve.

Thanks everyone for the help.
Joe

[phil-b]

Could it be a leaking pump diaphragm? Are the plugs the same color?

[billw]

quote Phil B:

Could it be a leaking pump diaphragm? Are the plugs the same color?

Ditto for me on this one. You can loosen the pump from the power head, put a couple of extra screws and nuts in the pump mounting holes to keep the pump from leaking externally, then pump the bulb hard and see if fuel comes out of the pump’s pulse hole. If it does, the diaphragm is no good.

Long live American manufacturing!

[bob]

What the gentlemen stated above is excellent advice.It could also be a compression problem.Check plugs and if they are very wet than probably flooded.Is gas dripping out of carb?(a little gas puddled in carb throat is usually OK)If dripping down then flooded.If this checks out OK,then it could be low compression.Having to pulls 7- 10 times even if a little flooded is an indicator.Once it runs and warms up then it will start much easier even with lower comprsession.You can check it with a compression gauge and should be 70 psi per cylinder or higher.(you may get away with a little lower).Another way to check your compression is after you start it and warms up will it idle down nice and low?If it does,then your compession is probably OK.Also,the little donut gasket that goes over the high speed nozzle in your carb can cause difficult starting.If flatened or crumbling apart should be replaced.Good luck.

[joesnuffy]

Thanks for the advice everyone.

The fuel diaphragm may just be the problem. I will check that today. Once the engine is warm if I disconnect the fuel line while the engine is running for like 4 seconds before killing the engine it starts right back up immediately normally 1 pull if I don’t 2-3 pulls.

The carb also stays dry no fuel oozing out of it when I pump up the fuel bulb I can hear fuel going into the carb then the fuel bulb gets hard to pump like normal and no fuel leaves or leaks out the carb. No fuel oozes out the carb while its running either.

The spark plugs run clean as and dry when the engine is running they only get wet on the initial start-up. Both plugs get nice and warm once running and engine warms up quick so thermostat is working. The plugs are also new but the old plugs I had in it up to yesterday were running dry and clean looking the were begging to clean up on their own the more I ran the engine the cleaner looking they became.

To start the engine initially cold I pump up the fuel bulb then disconnect the fuel line from engine set the speed to high speed then pull the rope like 7-10 times fuel actually shoots out the fuel fitting on engine then after like 5 pulls it tries to start but it normally takes a few more pulls.

Compression seems really good. I also put new plug wires on the engine and it will run very slow especially with the electronic modules it actually has a hard time stopping it idles down so low. The motor also had this problem with the points and condensers installed I forgot to mention that.

Joe

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