Kawasaki 23HP Twin Overheating

[sean donato]

Well it's pretty simple at this point, it not getting one of 3 things. I'm assuming the intake is clear and it had compression, since it did run. Which leaves fuel and spark. It's quite unusual for 2 coils to go out at once. You can verify spark with a cheap spark tester. Assuming that's fine it just leaves fuel issues. Pretty sure you've covered all the obvious and easy stuff at this point. Have tou had the carb off and physically apart to inspect it? Doesn't take much dirt/crud to screw up newer carbs. Fid you check the main jet fuel shut off solenoid to make sure it's working?

 

[djg james]

Well it's pretty simple at this point, it not getting one of 3 things. I'm assuming the intake is clear and it had compression, since it did run. Which leaves fuel and spark. It's quite unusual for 2 coils to go out at once. You can verify spark with a cheap spark tester. Assuming that's fine it just leaves fuel issues. Pretty sure you've covered all the obvious and easy stuff at this point. Have tou had the carb off and physically apart to inspect it? Doesn't take much dirt/crud to screw up newer carbs. Fid you check the main jet fuel shut off solenoid to make sure it's working?

How do you check the shut off solenoid to see if it's working?

 

[sean donato]

How do you check the shut off solenoid to see if it's working?

Take it out and let it plugged in, turn the key on. Should suck in. You may have to ground the body. Some of them you can pull the needle out of. Then just stick the body back in and run it to see if there's a difference. I have several plugs here I stick in for testing purposes.

 

[djg james]

Well now I'm really confused. I removed the pump's exit hose going to the carb and turned it over. No flow. I put the OLD pump back on leaving the same hose connected and I immediately got a good flow. Hooked up the carb and it would not catch.

Moved onto the solenoid. Unhooked the grown and tried to unthread it without disconnecting the second wire. It was sealed inside some shrink tubing. Fuel dripped out when I had it partially unthreaded. The engine fired when I tried it, but died after a second. Screwed the solenoid back in with the ground wire disconnected and tried it. It didn't catch. Screwed the ground wire back on and the engine fired up and ran half throttle without any surging. Ran it for a minute without issues and then drove the mower back into the garage.

So the NEW fuel pump was bad and the solenoid was working properly. The impulse line (which I changed any way) was a stout piece of tubing and did not collapse under vacuum as I thought might be happening. So what caused the original dying? The only thing I can speculate at is the spark plugs were overheating and failing. Kind of odd for both to go bad. Or maybe the extra cleaning I did WILL help.

Maybe the solenoid ground wire just needed cleaning causing it to fail when it got hot.

These are pretty thin guesses, but I don't know what else to look at. And sorry for giving you the play by play with every step I took. I do so because maybe I missed something simple.

Stay tuned as I try to mow the whole yard in one session.

And as always, thanks for your help.

NOW, back to the splitter

 

[sean donato]

The spark plugs didn't have anything to do with the issue, of that I'm quite certain. Check over the new fuel pump to be sure the impulse and in/out are in the same location as the old one. (Just to be sure.) My guess at this point would be the coil on the fuel shut off is failing once it gets hot.

 

[djg james]

The spark plugs didn't have anything to do with the issue, of that I'm quite certain. Check over the new fuel pump to be sure the impulse and in/out are in the same location as the old one. (Just to be sure.) My guess at this point would be the coil on the fuel shut off is failing once it gets hot.

Got it. As you can see and as I've said before, I'm no mechanic.

Just to be clear, the coil you mention is the solenoid I've been messing with?

Thanks

 

[sean donato]

Got it. As you can see and as I've said before, I'm no mechanic.

Just to be clear, the coil you mention is the solenoid I've been messing with?

Thanks

Yes. It's has a coil to produce a magnetic field to pull the plunger down/in to let fuel pass the main jet. If it's not working properly or the circuit goes open when it gets hot it will shut the fuel off to the carb. No fuel = no run. It's the best guess I got from what you've checked out and replaced.
Don't worry about not being a mechanic. Simple engine, easy to walk through diagnosis. Just process of elimination.

 

[nedsim]

Also check to make sure there's nothing preventing the plunger from making its full stroke. If the plunger doesn't seat completely in the energized (open) position, the solenoid will draw more current than it's designed for and heat up, which will raise the winding resistance, and possibly lower the current, and thus magnetic field, enough that the plunger closes until the solenoid cools enough to start the cycle over. If the solenoid gets hot enough that you can't hold on to it for 15 seconds or so, I'd dig deeper.

 

[djg james]

Last question. When a fuel pump fails, it fails for good? No starting and stopping like the situation I've seen. I'm ordering a new solenoid to have on hand in case. If the fuel pump can work intermittently then I'll order another one to have on hand in case it goes. If they fail all at once and then are done, I don't want to have one on hand setting around and have the rubber diaphragm dry rot.

 

[sean donato]

Usually the pulse type fade out as the diaphragm gets hard or it's a sudden thing. Diaphragm breaks/ tears or the flapper valves mess up. Never seen one work intermittent.

 

[Andy K]

I have a JD 757 that has the Kawasaki engine and it would run great for an hour and then would start sputtering as if it was running out of gas. I could usually limp it back to my shop using the choke. I chased my tail for about 4 days and then it hit me. I pulled the top off of the carb, exposing the fuel bowl. I could see where the float was actually rubbing against the side of the bowl causing it to "run out of fuel". I took a file and removed about .003 material where the rub mark was and it now runs like a champ! There is an issue with the engine running hot in this mower causing things to warp.

 

[djg james]

I have a JD 757 that has the Kawasaki engine and it would run great for an hour and then would start sputtering as if it was running out of gas. I could usually limp it back to my shop using the choke. I chased my tail for about 4 days and then it hit me. I pulled the top off of the carb, exposing the fuel bowl. I could see where the float was actually rubbing against the side of the bowl causing it to "run out of fuel". I took a file and removed about .003 material where the rub mark was and it now runs like a champ! There is an issue with the engine running hot in this mower causing things to warp.

Something to certainly consider. What model do you have? I have the FH680V 23HP twin. Did it do that from day one of you owning it? Mine only started doing it this year (10+ year old mower).

I've got a solenoid on order, and if it does that again, I'll replace it.

 

[Andy K]

Something to certainly consider. What model do you have? I have the FH680V 23HP twin. Did it do that from day one of you owning it? Mine only started doing it this year (10+ year old mower).

I've got a solenoid on order, and if it does that again, I'll replace it.

I believe mine is a FH680d 23HP horizontal shaft, I bought it from my nephew who had owned it since 06. He did lots of mowing at the college he attended to help pay for school and that was the same model they used. He figured if a bunch of drunk and hungover college guys couldn't tear it up that it had to be a great mower. It now has 840ish hours on it. It started having the fuel starvation issue at about 14 yrs old and about 700 hours.

 

[JimR]

Usually the pulse type fade out as the diaphragm gets hard or it's a sudden thing. Diaphragm breaks/ tears or the flapper valves mess up. Never seen one work intermittent.

My deceased neighbor had these same issues with a 27hp Briggs on his zero turn. He finally called me to change the fuel pump on it. After changing the pump he had the same issues. I tore into it and found a very slight crack on the impulse line. I replaced that line and his mower was running like new again. I know that you already changed that line. To me it sounds like a fuel issue. Like others have said. When it dies pull the carb line off the pump and spin the motor over. Does it squirt gas?. If no, loosen the gas cap and try it again. If still no gas then you definetly have an inline fuel problem. Another thing is that you can have crap in your fuel tank blocking off the outflow nipple.

 

[sean donato]

My deceased neighbor had these same issues with a 27hp Briggs on his zero turn. He finally called me to change the fuel pump on it. After changing the pump he had the same issues. I tore into it and found a very slight crack on the impulse line. I replaced that line and his mower was running like new again. I know that you already changed that line. To me it sounds like a fuel issue. Like others have said. When it dies pull the carb line off the pump and spin the motor over. Does it squirt gas?. If no, loosen the gas cap and try it again. If still no gas then you definetly have an inline fuel problem. Another thing is that you can have crap in your fuel tank blocking off the outflow nipple.

Not me, just helping @djg james out with his mower.

 

[JimR]

Not me, just helping @djg james out with his mower.

Ooops, he will see it.

 

[djg james]

Ooops, he will see it.

Yup, I saw it. I'll try to figure out a way to check. Then again, if plugged, why would it work initially and the stop after an hour and then restart once cool. I'm betting (hoping, praying, etc) that it's the solenoid. As @sean donato said, most likely, the fuel pump would fail for good. Not saying what you've mentioned couldn't happen, though. I will pop the line off to check flow if it happens again.

 

[JimR]

Yup, I saw it. I'll try to figure out a way to check. Then again, if plugged, why would it work initially and the stop after an hour and then restart once cool. I'm betting (hoping, praying, etc) that it's the solenoid. As @sean donato said, most likely, the fuel pump would fail for good. Not saying what you've mentioned couldn't happen, though. I will pop the line off to check flow if it happens again.

I'm just throwing it out there because I have seen this happen. I believe that you have a fuel starvation issue. To find it, you need to start at one end and work your way back or forward until you find the problem. That could also be crap in your carburetor. I would check the fuel source first before hitting the inside of the carb.

 

[lloyd786]

Fuel tank vent? Do you have suction in the tank if you open the cover?

 

[djg james]

Fuel tank vent? Do you have suction in the tank if you open the cover?

Caps are vented.