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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14440
Experience:  Certified on Onan and Generac generators
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I have an onan 4000 genset ky j series. it has voltage to solenoid.

Customer Question

I have an onan 4000 genset ky j series. it has voltage to solenoid. I cleaned nearly new carb and solenoid. It has spark at plug. runs with starter fluid then stops. It throws a 3 36 code. I have a manual and there is gas coming into bowl. I dont know what else it could be
Submitted: 5 years ago.
Category: Small Engine
Expert:  Hank F. replied 5 years ago.

Thank you for choosing Just Answer for the solution to your problem.
My name is Hank, and I am going to assist you with this.


First, please don't use starting fluid - it is very bad for an engine, and even worse on air cooled than liquid cooled. Instead, use gas or carb cleaner.


What you have done is clearly identified that you have a fuel issue - let's see if we can figure out why.

Will the set fire at all without spraying fuel into it?


Did you check the fuel shut off solenoid to see if it is working?


How old is the carb? "Nearly new" is kind of vague.


How long has it been since the genset was run with the new carb on it?


Exactly how did you clean the carb - and what did you use to clean it?


Please provide as much detail as possible.


Customer: replied 5 years ago.
The carb is less than a year old. it looked new inside. i used carb cleaner. there were a flew brown things inside. I tried to start it this weekend it started and quit twice. it started a third time and ran for maybe 15 seconds and quit again. it wants to start but wont unless i squirt in fluid then it dies again. its probably a 2001machine and has not been run much. i replaced the carb last year and it had been running. Its hard to access the insides of the machine since its set inside a compartment
Customer: replied 5 years ago.
The solenoid is new and it is working
Expert:  Hank F. replied 5 years ago.

Yes, this is not an easy set to access.


But from what you are describing, you are having a carburetor issue.



As gas gets old, it turns to varnish and clogs up the passageways inside the carburetor, not allowing enough gas to get to the engine.

This condition is cumulative. Every time gas sits, the varnish builds up just a little more, like coats of paint, until eventually gas can not flow. It will not happen overnight, but the symptoms can show up all of a sudden, even while simply stopping to refill with gas.

The use of fuel additives, such as Sta-Bil or Sea Foam will not stop this process from happening. They will greatly slow it down, but the gas will still go bad.


When this happens, either the engine simply will not start, or it will not run without the choke on (this reduces the amount of air getting pulled into the engine, changing the fuel/air mixture), or it will run but surges.


Another issue that varnish in the carb can cause is that the varnish may not allow the float needle to seal properly against the seat, causing the flow of gas to not shut off when the bowl is full. The result will be gas overflowing the carb and running into the cylinder, and possibly out the air intake. If the gas gets into the cylinder, it will seep past the rings and down into the crankcase. This will be evidenced by your oil level being over-full and/or the oil smelling like gas.


The only 2 solutions are to either replace the carburetor or give it a good, thorough cleaning.

When removing the carb, make sure to take a good picture, or make a good drawing of where all springs and linkages are attached. This will make reassembly much easier.

Most people believe that cleaning a carb involves removing the bowl and wiping it out, then spraying some carb cleaner through it.

This is simply insufficient.

To properly clean the carb, you must remove it, disassemble it (making sure to remove all non-metal parts), and soak it in a commercial solvent for several hours. Soaking it overnight is even better.

Then clean all solvent off with a spray type carb cleaner, making sure to get lots of cleaner into every hole and passage there is. Pay special attention to the tiny holes in the bore of the carb, under the throttle plate for the carbs that have these holes. Use lots of cleaner. And make sure to wear safety goggles to avoid getting the over spray into your eyes. There will be over spray.

Dry the carb with low pressure compressed air.

This is an EPA compliant carburetor, and as such, is not supposed to be taken apart or adjusted.

When you have an issue with it, you are supposed to replace the entire carb.

But, sometimes it is possible to clean them. Just remember, that as an EPA compliant carb, there are no parts available for it, so if you lose or break anything, you will definitely need to get a new one.


Occasionally, even a good cleaning is not going to be sufficient, and you may end up having to replace the carb anyhow. Be prepared for this.


Since you are seeing debris in the carb, it would also be a good idea to change the fuel filter.


If for some odd reason this does not help, please let me know so I can assist you further.



Customer: replied 5 years ago.
I will try that and soak the whole thing. do i have a time limit on getting back if that doesn't work
Expert:  Hank F. replied 5 years ago.

No, sir.

You take all the time you need.


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