John Deere D140 (1GXD140EKCC324968) 22 h.p. Briggs Model # 407777 Type # 0274G5 Code # 120224YG Runs perfect for about 10 min. then cuts out on one cylinder. Has new carb. kit, new plugs, new fuel filter, new air filter, new coils. Fuel tank is vented ok, no fuel lines kinked. disconnected the kill wires for the coils and still does it. Only thing I haven't replaced is the fuel pump because I disconnected the fuel line, turned the engine over and it shot fuel about 12-14 inches. I'm at a loss. Any help would be greatly appreciated. Thank you!
• Fuel tank is vented ok, no fuel lines kinked.
• Only thing I haven't replaced is the fuel pump because I disconnected the fuel line, turned the engine over and it shot fuel about 12-14 inches.
• How do you know the tank vent is OK ? What test did you use ? I ask this because the vacuum within the tank is tiny... infinitesimal... really small. Proabably only 1 or 2 millimeters of Hg. You'd need a laboratory-grade scientific instrument to measure this. If you drilled a 1/32" hole in the cap that's one thing, but if your test was using a 60psi compressed air nozzle, then that's not a good test. This is why I ask.
• Fuel spurting out of a disconnected fuel hose is a test of Volume. However, the requirement to get through the hose, fuel filter, and past the float needle requires Pressure. Those are 2 different qualities. You need a test that verifies fuel Pressure.
I think your tests are good initial tests, but not good enough to completely rule out the vent and fuel pump as "absolutely NOT the cause". And since you're so far into this problem, out of other possibilities, and obviously need some help... this is where I would look.
If it still runs on one cylinder it's doubful it's a fuel issue since they both use the same carb. One of your coils must be bad, If you can tell which cylinder keeps running and which one quits, swap the coils on each and see if the problem stays on the same cylinder or if it moves - this will confirm the bad coil. These sometimes get hot and stop working I think.
I removed the fuel cap so i know it is vented and the fuel pump is a impulse fuel pump I have made sure the impulse line is in good shape, and when I hold my thumb over the line I feel a lot of suction. I run the fuel line into a plastic water bottle and it fills rather quickly. As far as actual pressure, I have no real way to test it. Thanks!
If you know you have fuel and spark in the cylinder that quits I would be checking for a blown head gasket or a cracked intake manifold which opens up when hot.
I have tried it with the kill wires removed with no success, I did a compression test this morning and I have 150 on each cylinder. swapped places with the coils, still the same result, when the engine starts to miss and cut out it is always the same side. A huge thank you to everyone who has been trying to help it is very much appreciated.
This is a confusing issue, Makes no sense - Lets assume it's Not fire - now you will need to concentrate on fuel delivery , pump- filter- carb . You never say never in mechanical issues and cannot get too focused on one thing.
I've learned this the hard way. Looking back on your post I see you've checked the fuel system as well.
If it were me, I'd hook up a new fuel source with an electric fuel pump and see if anything changes
I ran into something like this and found my fuel line was sucking air - only figured it out after using an electric pump hooked up to a gallon bucket of fresh fuel , you never know.
As the saying goes
When you have eliminated all of the possible then only the improbable is left
On a twin cylinder with a single barrel carb when you have ruled out electrical you are left with fuel
And on your engine it can only be a leak at the inlet manifold ( there is a rubber seal there ) or a bad valve / cam lobe
A loose valve guide can cause random stumbles
