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SmilinSam

CH18 Kohler fuel line-or- Heat issue??

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SmilinSam
Whats the proper way to route the fuel line into the carb on a CH18 Kohler twin? My Super Cub was giving me fits and all I could find was that the fuel line was mashed down and hard dried between the air filter base and the tin on the head to the flywheel side of the valve cover. Thats where the line was routed from the pump into the carb on this one, but I have no idea if that was factory or not. 50% Crushed fuel line was starving the engine for fuel when it got hot and under a load.

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leeave96
I found the same deal on my CH18. My remedy was to have plenty of slack in the fuel line so it fit square through the opening instead of being pulled more diagonally and pinching the fuel line. Good luck, Bill

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PhanDad
Here's some pics of what I believe is the stock routing of the fuel line on the CH18 spec 62501 that was installed in my 75th:










In the pics it doesn't appear to be crushed and I don't remember an issue when I took it apart.

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SmilinSam
Well the mashed line wasnt the problem. Still runs from cold to about a half hour doing as much as you want. After that it starts acting up again when pulling the governor. You can keep it from dying by pulling the choke out and pushing it back in, but eventually that does not help while the PTO is engaged. Shut it off till cold, and you can go again for another half hour of hard work or so, then the process repeats. Its consistantly this way anyhow. Seems to me to be a heat/fuel issue. The only thing I can think to do is put a electric fan above the engine on the hood and try and force move the hot air from the compartment by bringing cool air in throgh the ducts on the top of the hood. ???

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SmilinSam
Other things to mention are I have switched to an electric fuel pump , located outside the hot engine compartment, and its working. There is a metal barbed union in the fuel line connecting 2 short pieces of hose where the original vacuum pump was. I will be replacing the whole fuel line I think and eliminate that ,but doubt that is the problem.

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PhanDad
Maybe an issue with the carb fuel shut-off solenoid? Heat causing it to only partially open or cycle restricting the fuel flow? I don't think the barbed union is the cause. The slight increased pressure drop should be easily overcome by the fuel pump.

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rpickle
Yes, BLT got me squared away. I cut the grass with it last week, but was using a nasty PTO-to-deck belt. Have new one to install along with a new tranny belt this evening before I cut again. Thanks for asking.

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ssmewing
This may or may not help but I had the same symptoms on an onan. The fix was the coil. The heat was causing the bad to coil to not work. I changed the coil and all was well. I thought it was a fuel problem also as sometimes some chock helped and other times it did not.

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1Litre
CH18 has magneto coils for each cylinder.I doubt that both shut down at the same time. If you pull the choke and it runs better it is lacking fuel. Check that the vent for the tank is working . It may be the cap or a seperate line. Do not remove the fuel shut down solenoid. Your muffler will eventually fail with the internals getting fractured and the seam and end caps will leak. That keeps unused fuel on the shut down of the engine to end up in the muffler and eventually ignite after shut down . Have you checked the fuel filter?

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Al
Hi, Sounds like some of the trouble we see with the ethanol blended fuel. 90% of our problems would go away if this stuff was banned. 1 alcohol draws water from the atmosphere and surplus water shows up in the carb bowls and tanks. 2 Alcohol is a strong solvent and corrodes and actually eats away the carb castings, and the steel float bowls are always rusty and often rusted through. 3. These new carbs are jetted REALLY lean to meet emissions, now you add a fuel that has about 10% less energy by volume than gasoline. You need larger jets, but they are not available, so you are running even leaner and hotter. Add the fact that this stuff in very short time causes varnish build up in the passages in these carbs. A very lean carb with a (for example .010 passage) gets a varnish build up of .001, this reduces the passage to .008 really lean. Now lets say you are very selective about the fuel you buy, (no alcohol)but you go to a station with a blender pump and buy the good no alcohol premium fuel. You dial it up, but the last guy bought ethanol, or worse if the pump also dispenses E85, you get about a half gallon or more of what the last person bought as it is left in the hose after the blender valve. We see a lot of engines that run a half hour to 45 minutes and sputter and die. Getting rid of the gasohol fixes it many times. In cars with fuel injection, the computer just converts the info from the oxygen sensor and changes the pulse width of the signal to the injectors to fix the mixture. On these engines you have carburator with no way to adjust the mixture. Al Eden

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SmilinSam
Tried running it with the side panel off and it still died after about half an hour. After that I made several small changes: 1) replaced the fuel filter with a kohler extra capacity filter 2) removed my plastic inline shutoff 3) shortened the fule line and raised it up to the level of the electric fuel pump and tried to eliminate any sharp bends. Ran it for about 90 minutes with no problems. Put the side panel back on and ran another hour with again no problems. All this on the same tank of gas I was using and having the above problems, and without adding any new gas to the tank. So, one of the 3 things done or a combination thereof? fixed my problem.

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