Johnson 40hp starts then quits

[blacktrain]

I have had other posts about the problems I have had with this motor and I would like to update. I have a 1995 Johnson 40hp (Model# J40ELE0) It has a new stator and cdi and a new primer solenoid, new plugs. Now the motor will start every time I hit the key, but runs only a second or two. I hit the key again and same result. Thank you for your help...

 

[racerone]

Is there any fuel in the carburetors ?

 

[blacktrain]

yes, if you open up the drain plug on the bottom of each carb. a lot of fuel comes out.

 

[Vandkanten]

Besure to run with right plugs: QL78C

Clean and check the plug wires, and also the wires from CDI to coils.
Clean all ground connections (use a small metal brush) and replace the wire harness connectors. Disconnect the killwire (black/yellow) at the CDI box.

 

[jakedaawg]

Are you aware of and do you use the throttle advance feature of the remote control? No offense intended, you would be surprised how many folks don't realize it exists. Matter of fact, I educated a new customer about just this today.

 

[jakedaawg]

Besure to run with right plugs: QL78C

Clean and check the plug wires, and also the wires from CDI to coils.
Clean all ground connections (use a small metal brush) and replace the wire harness connectors. Disconnect the killwire (black/yellow) at the CDI box.

I believe that champion QL78YC

 

[jakedaawg]

Disconnect the killwire (black/yellow) at the CDI box.

be aware, if you do this AND start the motor, it will be tricky to shut off should it run. It would however indicate a key switch/wiring issue. You would have to choke it off.

 

[blacktrain]

Yes, I am aware of the throttle advance feature,and use it all the time. I made up two new plug wires, tried that but had the same result. Now for some reason when I try to start it, it fires right up and runs perfect for 5-6 seconds then quits just as if you turned the key off. I haven't tried disconnecting the kill wire yet, I will try that and I will let you know what happens. I sure do appreciate everyone's help. Thanks...

 

[jakedaawg]

Yes, I am aware of the throttle advance feature,and use it all the time. I made up two new plug wires, tried that but had the same result. Now for some reason when I try to start it, it fires right up and runs perfect for 5-6 seconds then quits just as if you turned the key off. I haven't tried disconnecting the kill wire yet, I will try that and I will let you know what happens. I sure do appreciate everyone's help. Thanks...

I would begin my diagnosis this way:

remove plugs.
install open air gap spark checker
turn key to "run" position
use a remote start switch attached at small yel/red terminal of start solenoid.
Crank motor and see if you have spark.
if no, test key switch

doing above and not using key to crank motor for spark test rules out a false result. This mimics the run and quit condition you experience.

 

[jakedaawg]

Should you have spark the next thing I would verify would be a simple cleaning of the main jet in the carbs and the idle bleed orifices. Mainly because it's easy and free. After that cdi electronics dot com has a free trouble shooting guide for ignitions.

on another note...does it stay running if you turn the red lever on the primer solenoid 90 degrees?

 

[blacktrain]

I tried everything you have suggested and nothing worked, but when I turned the red lever on the primer it started and run perfectly.

I removed the solenoid and bench tested it and I hear a clicking sound so i presume the solenoid works, I went to our local dealer and purchased a repair kit that came with a new cover, gasket and lever with a small o-ring on the end of the lever. After carefully following the directions that came with the kit i put it all together and the motor will only run with the red lever in the open position. Does this mean its time for a new one? Thank you so much for all the appreciated help...

 

[racerone]

The fuel that goes into the engine with the primer valve OPEN bypasses all the carburetor circuits .----That clearly tell me and you that there is a problem with your carburetors.----There is no doubt in my mind that you need to look into your carburetors here. !!

 

[jakedaawg]

Racer is absolutely correct here. This assumes that you understand the two positions of the lever. Normal position is when the lever is in line with the body ofnthe solenoid. Manually open is when the lever is 90 degrees to the body of the solenoid. If that is the case then your carbs are plugged and need to be properly serviced. Or they were filled with oil due to a fuel restriction or running out of gas. Most likely is plugged jet. Use a parts breakdown and completely disassemble the carbs including the orifice hidden in the bowl.

 

[Fed]

Bumping the key in when it wants to die is pretty normal.

 

[blacktrain]

I cleaned the carburetors and now the motor starts right up but again it runs for a few seconds and shuts down. I tried both positions with the red lever on the solenoid and got the same result. Also I have noticed that with the key switch in the off position I have fire to the plugs. Key switch on or off I still have fire. Thanks again for all your help it is greatly appreciated...

 

[racerone]

Does the electric primer work when you push in the key, yes or no ?----Have you looked at the wires on your ignition switch and are they all tight and in place ?

 

[blacktrain]

Forgot to mention, when i unhook the black&yellow kill wire my spark improves greatly when hooked back up the spark is weak...

 

[blacktrain]

yes the electric primer is working when i hold in on the key switch....I took apart the remote and made sure the terminals were tight on the key switch...

 

[racerone]

Sounds like you need to go through the wiring harness.----Cut the shrink wrap of the cable and inspect each wire on it and the motor.

 

[jakedaawg]

Do you know how to use an ohm meter and do you have one?