'62 Johnson 5.5hp Difficult Cold Starting

[lindy46]

Working on a '62 Johnson 5.5hp. I've gone through everything and once I get it started it runs pretty good. It's just getting it started that's a pain. Takes 25-30 pulls before it even farts. Compression 75psi and even. All new electronics - points are properly set and cleaned with acetone. New wires, new plugs. Spark jumps a 3/8" gap. Carb cleaned and rebuilt. New hoses. Did a decarb with Seafoam. Even spraying premix directly into the cylinders won't give a sputter when cold. You just have to yank and yank and finally she sputters, then starts. Low speed needle is open 1.25 turns (yes, I cleaned under the freeze plug), but high speed is only open 1/8 turn. Any more and she dies. Good fuel pump. Any ideas?

 

[racerone]

Why is the high speed only open 1/8 turn ?-----Does choke plate close and stay closed when pulling it over ?-----Does spark jump a gap of 1/4" or more?-----Do you use the marking on the throttle grip as the " gospel " for start ?-----You may need to open throttle more for start up.----Answering each question is the path forward.

 

[OptsyEagle]

Also, on that motor, if I recall, the throttle butterfly gets opened just a little when the choke lever is pulled out. I suspect the benefit of having the throttle set to start when starting is simply for when it starts and you push the choke back in. In any event, I can't remember if the mechanism that opens the throttle butterfly a little upon choking is something that you need to connect when rebuilding the carb or not. In any event, take a close look at the left side of the carb where the throttle butterfly connects and see if it opens a little when you pull out the choke. If it doesn't then that may be your problem. If it does, then I am at a loss.

You could also look to ensure that your carb is synchronized with your throttle cam. The mark on the cam should hit the middle of the carb roller just as your carb starts to open. If it doesn't, there should be two hex nuts on the starboard side of the throttle cam to adjust it. With this check, you definitely want to make sure your choke knob is pushed in. Don't ask me why I know that but I am at least 3 hours older then I should be because of that and I am not going to get that time back. lol.

 

[lindy46]

Why is the high speed only open 1/8 turn ?-----Does choke plate close and stay closed when pulling it over ?-----Does spark jump a gap of 1/4" or more?-----Do you use the marking on the throttle grip as the " gospel " for start ?-----You may need to open throttle more for start up.----Answering each question is the path forward.

If I open the high speed needle more than that, the motor stalls out once I get it started. Choke plate closes properly and stays closed when choke is engaged. My spark tester is set at 3/8", so that is where I checked it. Spark was strong and snappy. When starting, I turn the throttle grip to the neutral stop - I never rely on the markings on the throttle grip.

 

[lindy46]

Also, on that motor, if I recall, the throttle butterfly gets opened just a little when the choke lever is pulled out. I suspect the benefit of having the throttle set to start when starting is simply for when it starts and you push the choke back in. In any event, I can't remember if the mechanism that opens the throttle butterfly a little upon choking is something that you need to connect when rebuilding the carb or not. In any event, take a close look at the left side of the carb where the throttle butterfly connects and see if it opens a little when you pull out the choke. If it doesn't then that may be your problem. If it does, then I am at a loss.

You could also look to ensure that your carb is synchronized with your throttle cam. The mark on the cam should hit the middle of the carb roller just as your carb starts to open. If it doesn't, there should be two hex nuts on the starboard side of the throttle cam to adjust it. With this check, you definitely want to make sure your choke knob is pushed in. Don't ask me why I know that but I am at least 3 hours older then I should be because of that and I am not going to get that time back. lol.

When you engage the choke, the cam follower pulls away from the cam, opening the throttle butterfly slightly. I did set up the link & synch and it is right on. I thought of pulling the intake manifold and look for problems there, but that wouldn't explain why the motor won't even sputter when gas is squirted into the cylinders. I'm now about 10 hours older due to this motor and the customer sure won't want to pay me for my time if I can't produce a good running motor. Oh well, I'm retired and needed something to do!!

 

[OptsyEagle]

Any chance that the spark plug boots are reverse and now go to the wrong cylinders? A quick switch should confirm it, since these motors should start with one pull.

 

[racerone]

Nuetral stop on a 5-1/2 model ????

 

[HighTrim]

Lindy, I know you know what you are doing, so not trying to be rude by some of these but what I can come up with.

Gasket installed on the main center nozzle in carb? Thick donut gasket, or 201B o ring.

Is the exhaust plugged? In that I mean there is not enough air flow to atomize and pull fuel from the carb to the combustion chamber efficiently. Have you pulled the exhaust cover?

What plugs are you running? Have you tried a spare set to verify?

EDIT: Just saw that you tried pre mix direct in the cylinder. Should pop like that. I wonder if there is a crank case leak?

 

[S.A. Baker]

Point gap is?.... Dosn't need to be off by much to cause hard starting! Been there!

 

[lindy46]

Lindy, I know you know what you are doing, so not trying to be rude by some of these but what I can come up with.

Gasket installed on the main center nozzle in carb? Thick donut gasket, or 201B o ring.

Is the exhaust plugged? In that I mean there is not enough air flow to atomize and pull fuel from the carb to the combustion chamber efficiently. Have you pulled the exhaust cover?

What plugs are you running? Have you tried a spare set to verify?

EDIT: Just saw that you tried pre mix direct in the cylinder. Should pop like that. I wonder if there is a crank case leak?

Yeah, the thick gasket on the main nozzle is new and in place. Haven't pulled the exhaust cover - something to check. Motor had J8C's and I switched to new J6C's. The cover actually calls for J4C's.

 

[lindy46]

Point gap is?.... Dosn't need to be off by much to cause hard starting! Been there!

Right on 0.020" and points are clean.

 

[racerone]

Model # of the motor ?

 

[lindy46]

CD19

 

[racerone]

Is there a nuetral stop on the CD models ?

 

[lindy46]

No, you're right, there isn't. I've been setting the throttle between "start" and "fast" - probably closer to "fast" in my attempts to start it.

 

[racerone]

You need to look at the 1/8 turn open on the high speed jet.----NOTE , all the fuel comes through the high speed jet , even for starting.

 

[lindy46]

You need to look at the 1/8 turn open on the high speed jet.----NOTE , all the fuel comes through the high speed jet , even for starting.

Yeah, sort of strange. But once it's running, it immediately dies if I open it up any more. I obviously checked the needle and it is fine. I guess I could try another needle - I have a couple on hand. Possibly the orifice is defective? I've seen that before, but on the slow speed orifice. Interesting - when they brought the motor to me, it would hardly run at all. I pulled the carb and the slow speed needle tip was actually broken off and plugging the orifice. Couldn't get the tip of the needle out of the orifice, so I replaced the top half of the carb and the slow speed needle with one I had on hand. Maybe I should go ahead and replace the bowl also. That still doesn't explain why the motor doesn't pop when I spray premix directly into the cylinders.

 

[OptsyEagle]

Did you look at the spark plug wires. If they are switched it will never pop, start or run.

 

[AlTn]

Chine's thoughts on post #8 concerning the carbon build up, crankshaft seal leaks, or crankcase seam leaks bear looking into....what else you got to do besides pull the powerhead?...as a friend of mine said," Retired means your time is worth nothing."...he was only half joking.

 

[lindy46]

Did you look at the spark plug wires. If they are switched it will never pop, start or run.

Yeah - they're correct.