Kohler 4cz23 Genset hates me

[Technologic80]

When I first bought my boat, the genset ran fine. But would turn itself off after about 10 minutes. No biggie, we would just time it to be done with whatever (coffee maker, microwave) by then. It wasnt that much of an inconvenience but I definitely noted its odd behavior.

I changed the impeller, checked the sea strainer assuming it was getting too warm. No difference.

It finally shut down 3 weeks ago and hasnt restarted since. It did this once before and I was able to get it running again by tapping the fuel pump and carb bowl with the plastic end of a screwdriver, then putting carb cleaner into the carb to get it to start. Thats not working any more. Ive got plenty of fuel going IN to the fuel pump. I dont even know where the fuel line goes IN to the carb to check.

Its a 1997 Kohler 4cz23 gasoline 4kw genset with 5, yes 5 hours. New plugs, new air filter, just changed the oil (kohler oil filter/10w40 oil as recommended), new Kohler genuine impeller. When it runs (I have oil & temp gauges) both are in the perfect operating range - the temp never leaves 160 degrees and the oil psi stays right around 50-60psi.

SOMEBODY PLEASE help me before I set fire to my hair and shoot this generator to the moon!!! :facepalm:

 

[rbh]

Re: Kohler 4cz23 Genset hates me

When I first bought my boat, the genset ran fine. But would turn itself off after about 10 minutes. No biggie, we would just time it to be done with whatever (coffee maker, microwave) by then. It wasnt that much of an inconvenience but I definitely noted its odd behavior.

I changed the impeller, checked the sea strainer assuming it was getting too warm. No difference.

It finally shut down 3 weeks ago and hasnt restarted since. It did this once before and I was able to get it running again by tapping the fuel pump and carb bowl with the plastic end of a screwdriver, then putting carb cleaner into the carb to get it to start. Thats not working any more. Ive got plenty of fuel going IN to the fuel pump. I dont even know where the fuel line goes IN to the carb to check.

Its a 1997 Kohler 4cz23 gasoline 4kw genset with 5, yes 5 hours. New plugs, new air filter, just changed the oil (kohler oil filter/10w40 oil as recommended), new Kohler genuine impeller. When it runs (I have oil & temp gauges) both are in the perfect operating range - the temp never leaves 160 degrees and the oil psi stays right around 50-60psi.

SOMEBODY PLEASE help me before I set fire to my hair and shoot this generator to the moon!!! :facepalm:

Do you have the book for the gen set?
The newer models have auto shut down for various reasons, low oil, overheating "ETC"
Go through the book or get a tech to look at it.

I know thats not alot of help, but if you have fuel and spark and its running cool with enough oil and you are not overloading the circuit, I don't have a place to start from to look for the problem.

 

[Fireman431]

Re: Kohler 4cz23 Genset hates me

Kohler has 11 different shut-down failsafes to save the generator. Call a service tech. You could spend days trying to trouble shoot an errant electrical code and wind up doing more harm than good.

On a side note, it certainly sounds like it has a fuel deliver issue. Most twin cylinder Kohlers have two separate fuel pumps. A hig pressure and a low pressure (for lack of proper terms). One is available at Autozone. One is around $350.

Best of luck.

 

[Technologic80]

Re: Kohler 4cz23 Genset hates me

I guess I shoudve cliffnoted my original post.

I have plenty of spark. No fuel is getting past the carb.

Although my Kohler isnt as sophisticated as the new ones (I have 4 fail safe triggers - oil psi, exhaust temp, block temp, and ac output), those are all bypassed as you are starting the unit. Once you let go of the start button, THEN the engine would stall right away if one of those circuits was tripped.

I cant get the unit to fire unless I spray carb cleaner in the throat of the carburetor. Once the carb cleaner gets burned (2 seconds), it stalls. If I give it a continuous spray, it keeps on running happily. NOT the same behavior as a fail safe, where it would start normally and then stall after you release the start button, thus ending the safety circuit bypass. Mine will just crank and crank and crank until you manually input some kind of combustible into the carburetor throat.

Anyway, the fuel pump is in a ridiculous spot for me to replace it. It could be the anti-diesel solenoid too. Another item in a hard to get at spot. I have a technician coming out tomorrow to diagnose. Ill keep the board updated!

 

[Fireman431]

Re: Kohler 4cz23 Genset hates me

Have you checked all of the reset-able breakers? There are one or two on your unit. One is for the fuel flow, I believe.

 

[rbh]

Re: Kohler 4cz23 Genset hates me

Almost sounds like the problem I had with my onan emerald, the little board was fried.
When you hit the starter the board is bypased I "think" (or there is a starting circuit) and if you pull off the starters main power cable and then pull off the electric fuel pumps + lead, hook up a multi meter or a test light you should have power there when you hit the start button.
No power- possible issues, board, wireing harness, breakers.

 

[Technologic80]

Re: Kohler 4cz23 Genset hates me

Ah HA!

Ive made slight progress... went out to the boat, tested the fuel pump. Plenty of fuel at around 4psi!

Removed the carburetor (keep in mind - Ive NEVER worked on a carb). Brought it inside, removed the bowl. It had at least a teaspoon of crap in the bowl Looked like grit.

Cleaned the bowl and the whole carb out with carb cleaner and a can of compressed air. Re-installed. Still no start Again, if I put carb spray in the carb, it starts right up but stalls out when that runs out. My carb bowl was full of gas. Gas isnt making it up from the bowl to the intake.

Now I just figured out I should've checked the "jets". I had no idea. From what Ive read on the web, the jet is the tube that comes down by the float, right? Do I remove that? When I looked up that tube, there was what looked like a screw (the jet?) with a slot, like you could unscrew it with a small screwdriver.

Should I go remove the carb again, remove the bowl, and unscrew the thing up in the tube? Any advice is appreciated.

 

[rbh]

Re: Kohler 4cz23 Genset hates me

Ah HA!

Ive made slight progress... went out to the boat, tested the fuel pump. Plenty of fuel at around 4psi!

Removed the carburetor (keep in mind - Ive NEVER worked on a carb). Brought it inside, removed the bowl. It had at least a teaspoon of crap in the bowl Looked like grit.

Cleaned the bowl and the whole carb out with carb cleaner and a can of compressed air. Re-installed. Still no start Again, if I put carb spray in the carb, it starts right up but stalls out when that runs out. My carb bowl was full of gas. Gas isnt making it up from the bowl to the intake.

Now I just figured out I should've checked the "jets". I had no idea. From what Ive read on the web, the jet is the tube that comes down by the float, right? Do I remove that? When I looked up that tube, there was what looked like a screw (the jet?) with a slot, like you could unscrew it with a small screwdriver.

Should I go remove the carb again, remove the bowl, and unscrew the thing up in the tube? Any advice is appreciated.

I think thats your main jet your describing, get a book for your carb and you will need compressed air to blow out the circuits and some fine wire
- low/idle, midrange, high speed and your choke circuits (are the butterflies hanging up in the ventury?)

 

[Technologic80]

Re: Kohler 4cz23 Genset hates me

I think thats your main jet your describing, get a book for your carb and you will need compressed air to blow out the circuits and some fine wire
- low/idle, midrange, high speed and your choke circuits (are the butterflies hanging up in the ventury?)

Thanks for the reply!

Well good news (I think?). Brought the carb back in, cleaned it again. Paid special attention to the float. The float needle has a rubber tip that had significant crust on it. I cleaned it off very good and cleaned the bore of the float needle.

Reinstalled, started RIGHT UP!!!!

It was hunting quite a bit, it only would do that before once in a while, so Im going to lube the linkages first. I also played with the mixture screw so maybe I didnt turn it as many times as I thought.

NEXT: INSTALL A SMALL MICRON FUEL FILTER!!!!!! Heres what I drained from the bowl the first time:

 

[rbh]

Re: Kohler 4cz23 Genset hates me

Thanks for the reply!

Well good news (I think?). Brought the carb back in, cleaned it again. Paid special attention to the float. The float needle has a rubber tip that had significant crust on it. I cleaned it off very good and cleaned the bore of the float needle.

Reinstalled, started RIGHT UP!!!!

It was hunting quite a bit, it only would do that before once in a while, so Im going to lube the linkages first. I also played with the mixture screw so maybe I didnt turn it as many times as I thought.

NEXT: INSTALL A SMALL MICRON FUEL FILTER!!!!!! Heres what I drained from the bowl the first time:

View attachment 166749

YUP thats YUCK!!

Air fuel mixture, start at I think 3 turns out, motor under load back out till it starts to chug 1/4 to 1/2 back in.

 

[Fireman431]

Re: Kohler 4cz23 Genset hates me

When cleaning the carb, turn each screw in while counting the turns...just until it seats. When reinstalling them, seat the screws gently and then back them out the number of turns earlier noted. No offense to anyone who posts, but unless the manual says 3 turns out, you're liable to never have that thing running correctly.

Also, there is more than just the main jet. There is a high idle, midrange (main), and a low speed jet. Each one should be removed, cleaned out with a rigid tool (wire welder tip cleaning tool is perfect), sprayed, and reinstalled. New gaskets are a must, even if the old ones look good. Air leaks cause the majority of carb problems on a rebuild/cleaning. Pay attention to the float, making sure it moves freely up and down and that the needle and seat are clean and mate up properly. All in all, should take only an hour or two.

 

[rbh]

Re: Kohler 4cz23 Genset hates me

If you need to download the manual try here.

http://lawnandgarden.manualsonline.com/manuals/mfg/kohler/35cfz_4cz_5cfz_65cz.html?idRes=2024507

You can change jets, you can not adjust them. And I think there are only two places on these carbs that can be adjusted, air fuel and the idle.
3 turn out is a base line I have used on many motors for setting the air fuel mix a turn one way or another does not make a big deal as you will be turning it in, then out, to find that sweet spot.

 

[Fireman431]

Re: Kohler 4cz23 Genset hates me

Just for clarification, I said they need to be cleaned, not adjusted. Jets are seated in all the way, with fuel and air moving thru. The biggest problem is old fuel and random crap clogging them up.