73 JDX 4 295 Kohler fuel issue

[Mailman]

After we finally got some snow I decided to get my X4 out for a run. At the start it ran with no issues at all but as I put a few miles on it, it would stop like it ran out of fuel, I would prime it up with a primer bulb I had installed a few years back and off we would go. Finally it got to where it would hardly run without pumping the bulb all the time. I checked the fuel line fitting inside the tank and found that the line and check valve had came loose and dropped into the tank. I replaced the line (blue) and check valve and it seemed to take care of the problem but when I got about a mile away it stopped and couldn't get it started. One question is can you use the blue fuel line for inside the tank on the check valve? Another thing is when I get it in the shop I am going to check the vacuum line from the crankcase to make sure it is on. Question no. two is should a person use tygon line instead of the blue line especially on the inside of the tank with the check valve? Oh yes I have converted the Walbro carb to a Mikiuni VM-34.

[Steven Rempel]

thoughts, is your tank vent blocked, have you tried running a mile or two with the cap on lose? with a mikiuni carb how is the fuel pump, new, old, weak?

the drop line in the tank is best if it is a stiffer type of line I find
just my thoughts

[Mailman]

I'll try the loose cap once, the fuel pump is one I took off another machine but when I put it on the X4 I rebuilt it with a new kit. When you talk about a stiff line into the tank do you mean poly or could it be rubber? Also the vacuum line from the engine block is ok.

[Mailman]

Well I put a 12" piece of rubber hose on the check valve and fastened it with wire instead of a clamp and also wired the fuel line, the fuel filter, and both sides of the primer bulb so there was NO air leaking around the fitting and that seemed to solve the problem. I ran it about five miles and didn't stop or miss one time so must of been enough vacuum leaking before to cause it to loose it's prime.

[Steven Rempel]

when I read the overhaul manual they mention that the line should be stiff so as the pick up will not be flopping around in the tank and possible grabbing air when running with low fuel.

the impulse line from the crank case you also want a stiff type line so when the engine is hot the heat does not soften the line causing weak impulse which would then make for a poor fuel pump performance.


I find that if I use old fuel line the is still flexible but has hardened up over the last few year is a good option. I seam to be replacing fuel line every 5 years or so. So I just reuse a small length of that aged fuel line for inside the tank and the impulse line.