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CV740 dies after getting hot....at my wits end on this
#1
D
dbrunone
D
dbrunone
This has been an ongoing problem for 2-3 years now and I'm completely out of ideas, at my wits end with this damn thing. Unit is a Ferris IS3000Z zero-turn with a Kohler CV740 27hp motor.
Problem: pretty consistently 15-20 mins into mowing my lawn, especially if it is thick and the motor is stressed, the thing will just die. BUT, if I quickly turn off the blade and pull the choke, I can keep it running. Going back to Run will kill it right away. After it does this, it doesnt run right for the rest of the day or sometimes longer. I'm mostly able to get it back to the garage in "full choke" although sometimes it dies doing that too, and I need to crank it a lot to re-start it.
If I can get it re-started in the garage and get the choke to run, it will surge up and down, or sometimes die completely. The infuriating thing is, sometimes (like last week) it will do the whole lawn perfectly with no issues.
Things I've done to try to remedy in the past 6 months:
Hunting goes something like this (this vid is from last year):
Here are the valves:
PLEASE help, I'm about to sledgehammer this thing....
Problem: pretty consistently 15-20 mins into mowing my lawn, especially if it is thick and the motor is stressed, the thing will just die. BUT, if I quickly turn off the blade and pull the choke, I can keep it running. Going back to Run will kill it right away. After it does this, it doesnt run right for the rest of the day or sometimes longer. I'm mostly able to get it back to the garage in "full choke" although sometimes it dies doing that too, and I need to crank it a lot to re-start it.
If I can get it re-started in the garage and get the choke to run, it will surge up and down, or sometimes die completely. The infuriating thing is, sometimes (like last week) it will do the whole lawn perfectly with no issues.
Things I've done to try to remedy in the past 6 months:
- Replace ignition modules (incl plug wire) with new, using a kit Kohler recommends which eliminates the spark advance module and goes to a "fixed" timing system (this is the part they direct you to buy when looking up old ignition module numbers)
- New spark plugs
- Checked continuity of all wires going to ignition system
- Checked spark with a spark tester
- New fuel filter
- New fuel pump
- New carburetor
- Checked compression (even while its acting up), I get ~150psi on both cylinders which is what the book recommends
- Took fuel hose off carburetor and cranked it, watching fuel pump rate (looking for clogged lines). Was fine on all tank selectors
- Took off valve covers and watched valves actuate while cranking. Nothing abnormal.
- Shop 2.5 years ago replaced head gasket thinking that was the problem
- Different shop recently blew out all fuel lines with air and cleaned fuel tanks
- Ran a bunch of Seafoam through it in the fuel
Hunting goes something like this (this vid is from last year):
PLEASE help, I'm about to sledgehammer this thing....
#2
I
ILENGINE
I
ILENGINE
Sounds like starving for fuel. Pulling the choke about proves it. Since all the normal parts have been replaced. Just a though next time it starts doing then feel the carb bowl, and see if it is getting hot to the touch. Since everything has been replaced I am wondering if getting heat from exhaust causing fuel to boil in carb bowl.
#3
Hammermechanicman
Hammermechanicman
Does sound like vapor lock. Check the. Cylinder cooling fins for animal stuff. Check that no exhaust gas leaking near carb. When the engine start surging spray some water on the carb and fuel line to cool them and see if it changes how it runs. Might take some aluminum foil and make a heat shield to put between carb and engine/muffler and see what happens.
#4
StarTech
StarTech
Or could be like few engines that I saw the last few Springs here where Winter gasoline is boiling in the fuel lines and filter during our hot Spring weather from the exhaust heat. I can actually see it bubbling in the clear filters. The only solution so far has been to insulate the fuel lines. Once Summer gasoline mix start being at the fuel depots the problem went away.Sounds like starving for fuel. Pulling the choke about proves it. Since all the normal parts have been replaced. Just a though next time it starts doing then feel the carb bowl, and see if it is getting hot to the touch. Since everything has been replaced I am wondering if getting heat from exhaust causing fuel to boil in carb bowl.
#5
A
arch252
A
arch252
I had this happen on a 17hp Kawasaki. I added a brush guard to a JD LX279 and the side plate of the brush guard was redirecting some of the exhaust toward the carb, getting it hot and causing a vapor lock.
#6
D
dbrunone
D
dbrunone
SOLVED!!! After 3 years and over $1500 and several full days of my time thrown at this thing, I finally found the problem. And it is as stupid as you'd think. I even spent a whole day tearing off the heads and replacing head gaskets thinking that might be the issue.
At the suggestion of my father in law's mechanic friend, I ran a temp wire straight from the battery + terminal to the fuel solenoid on the carburetor. BAM, thing fired up instantly and ran perfectly.
Bottom line is, although I measured 12.5V at the solenoid connection point, something is pinched or frayed somewhere to the point where it can't deliver the proper amperage, causing the fuel solenoid to drop out sometimes, especially after ~20min of use. Unbelievable, never seen anything like it.
At the suggestion of my father in law's mechanic friend, I ran a temp wire straight from the battery + terminal to the fuel solenoid on the carburetor. BAM, thing fired up instantly and ran perfectly.
Bottom line is, although I measured 12.5V at the solenoid connection point, something is pinched or frayed somewhere to the point where it can't deliver the proper amperage, causing the fuel solenoid to drop out sometimes, especially after ~20min of use. Unbelievable, never seen anything like it.
#7
K
keakar
trace the wire back to the switch and see if that fixes it, if not then its between thew switch and the engine and might just be in the plug for the engine
K
keakar
well you are not solved just yet, that still needs to run through the main switch so the solenoid only gets power when key is on or the solenoid drain the battery and/or burn up or both but it will also flood the engine with gas while it sits unused since that is what the solenoid it there to stopSOLVED!!! After 3 years and over $1500 and several full days of my time thrown at this thing, I finally found the problem. And it is as stupid as you'd think. I even spent a whole day tearing off the heads and replacing head gaskets thinking that might be the issue.
At the suggestion of my father in law's mechanic friend, I ran a temp wire straight from the battery + terminal to the fuel solenoid on the carburetor. BAM, thing fired up instantly and ran perfectly.
Bottom line is, although I measured 12.5V at the solenoid connection point, something is pinched or frayed somewhere to the point where it can't deliver the proper amperage, causing the fuel solenoid to drop out sometimes, especially after ~20min of use. Unbelievable, never seen anything like it.
trace the wire back to the switch and see if that fixes it, if not then its between thew switch and the engine and might just be in the plug for the engine
#8
D
dbrunone
Right, obviously I disconnect the wire when not running the mower. I will troubleshoot the wire but at least I know what I'm looking for now, instead of wondering whether its a valve problem or clogged fuel port or something else.
D
dbrunone
well you are not solved just yet, that still needs to run through the main switch so the solenoid only gets power when key is on or the solenoid drain the battery and/or burn up or both but it will also flood the engine with gas while it sits unused since that is what the solenoid it there to stop
trace the wire back to the switch and see if that fixes it, if not then its between thew switch and the engine and might just be in the plug for the engine
Right, obviously I disconnect the wire when not running the mower. I will troubleshoot the wire but at least I know what I'm looking for now, instead of wondering whether its a valve problem or clogged fuel port or something else.
#9
Scrubcadet10
Scrubcadet10
that solenoid is not there to stop the engine from flooding,, that is more or less the float needles job, that solenoid is supposed to prevent backfire. Or "afterfire"well you are not solved just yet, that still needs to run through the main switch so the solenoid only gets power when key is on or the solenoid drain the battery and/or burn up or both but it will also flood the engine with gas while it sits unused since that is what the solenoid it there to stop
trace the wire back to the switch and see if that fixes it, if not then its between thew switch and the engine and might just be in the plug for the engine
#10
K
keakar
it is there as a backup secondary safety to shut off fuel to starve the engine and shut it down
backfiring is only related to timing or improper valve adjustment
K
keakar
lol, WRONG !!!that solenoid is not there to stop the engine from flooding,, that is more or less the float needles job, that solenoid is supposed to prevent backfire. Or "afterfire"
it is there as a backup secondary safety to shut off fuel to starve the engine and shut it down
backfiring is only related to timing or improper valve adjustment
#11
Scrubcadet10
Scrubcadet10
I've never heard it described that way.
Type 'afterfire fire solenoid " into Google and see what comes up.
"but it will also flood the engine with gas while it sits unused since that is what the solenoid it there to stop"
That is wrong because it happened to me, Kohler courage 19, needle failed and filled the crankcase up with gas. My solenoid didn't stop it.
Many engines don't have those and rarely flood... Why? The needle is doing that job.
Type 'afterfire fire solenoid " into Google and see what comes up.
"but it will also flood the engine with gas while it sits unused since that is what the solenoid it there to stop"
That is wrong because it happened to me, Kohler courage 19, needle failed and filled the crankcase up with gas. My solenoid didn't stop it.
Many engines don't have those and rarely flood... Why? The needle is doing that job.
#12
B
bertsmobile1
B
bertsmobile1
Sorry Keakar but you are mistaken
The only reason the the solenoid is there is to comply with EPA regualtions to prevent the engine drawing fuel through the carb main jet and pumping unburned fuel out the muffler after your turn the engine off during those last few revolutions.
BEcause the engines run very lean now days the mufflers are red hot internally and when the air fuel ration becomes correct for burning at atmospheric pressure it ignites in the muffler causing what is called an "afterfire"
To prevent all the "freedom fighting rednecks" ripping them off they get called an "anti- afterfire" device and not an EPA device.
The only reason the the solenoid is there is to comply with EPA regualtions to prevent the engine drawing fuel through the carb main jet and pumping unburned fuel out the muffler after your turn the engine off during those last few revolutions.
BEcause the engines run very lean now days the mufflers are red hot internally and when the air fuel ration becomes correct for burning at atmospheric pressure it ignites in the muffler causing what is called an "afterfire"
To prevent all the "freedom fighting rednecks" ripping them off they get called an "anti- afterfire" device and not an EPA device.
#13
B
bertsmobile1
B
bertsmobile1
And it does not stop the engine from flooding when not in use.
Again EPA regulations do not allow any part of the fuel system to be open to the atmosphere so if the float needle fails the carb bowl will fill up to the point that fuel will come out of the air vent passage then run down the carb & into the engine totally bypassing the main jet .
I see this every day in the work shop . It is very very common & because some ego with poo where it's brain should be posted on Y-tube that the solenoid prevents the engine flooding when not in use then all the other equally brainless fools perpertated they myth because they were too lazy to think it through properly. till eventually it became an undisputed fact
Again EPA regulations do not allow any part of the fuel system to be open to the atmosphere so if the float needle fails the carb bowl will fill up to the point that fuel will come out of the air vent passage then run down the carb & into the engine totally bypassing the main jet .
I see this every day in the work shop . It is very very common & because some ego with poo where it's brain should be posted on Y-tube that the solenoid prevents the engine flooding when not in use then all the other equally brainless fools perpertated they myth because they were too lazy to think it through properly. till eventually it became an undisputed fact
#15
C
cbs123
C
cbs123
It probably serves both purposes, but itn does indeed prevent shutdown backfiring. A common problem on motors before fuel solenoids. Fuel would spray into the hot exhaust and "backfire"lol, WRONG !!!
it is there as a backup secondary safety to shut off fuel to starve the engine and shut it down
backfiring is only related to timing or improper valve adjustment
#16
B
bertsmobile1
However the later is a side effect and should never be considered as an intentional us.
These fail regularly both in the closed & open position
More than one mower has turned up with the kill wire removed from the magneto so the owner was relying upon the solenoid to shut the engine off rather than finding the electrical problem & fixing it.
B
bertsmobile1
Yes in practice it stops the after fire and in doing so kills the engine.It probably serves both purposes, but itn does indeed prevent shutdown backfiring. A common problem on motors before fuel solenoids. Fuel would spray into the hot exhaust and "backfire"
However the later is a side effect and should never be considered as an intentional us.
These fail regularly both in the closed & open position
More than one mower has turned up with the kill wire removed from the magneto so the owner was relying upon the solenoid to shut the engine off rather than finding the electrical problem & fixing it.
#17
Hammermechanicman
Hammermechanicman
Those afterfire solenoids are a regular reason for folks bringing riders in to work on. Open coil, wire broke off, rubber tip turned to goo, rubber tip turned hard, plunger stuck open, plunger stuck closed. Kohler seems to think their solenoids are special even though they fail more than others. I have used OEM ones and the $15 chineese ones. Hate to say it but the $15 solenoids work just as good as the OEM ones.