Fighting what I think is a fuel issue

kspring61 · Oct 5, 2020

UPDATE: So I started to drain the tank this morning, had a fuel can underneath the tractor, pulled the line off the fuel pump and fuel started coming out at a nice steady stream. Over the next several minutes the stream of fuel started slowing until finally just a dribble. So I was like "hey, here is the issue, must be plugged". So I took off the fuel cap and as I started unscrewing it I hear a swoosh of air and the fuel immediately starts flowing full stream out of the fuel line and into the can. So to test that the cap indeed was not venting I screwed it back in and again after several minutes the fuel starts slowing down and after a bit it is a slow dribble again. So unscrew the cap and I hear "swoosh" and the fuel starts flowing again full force.

So, I am assuming my vented cap is not venting correctly. Anyway to clean these or is it just a new cap (probably best option) and does anyone know the part number?

LouNY · Oct 5, 2020

Is your fuel cap vented or does your fuel tank have a vent hose?
It could be a plugged fuel tank vent line.

kspring61 · Oct 5, 2020

LouNY said:
Is your fuel cap vented or does your fuel tank have a vent hose?
It could be a plugged fuel tank vent line.

Looks like a vented cap, inside plastic has one large hole and 4 small holes around it.

LouNY · Oct 5, 2020

Yes it does and looking at the parts breakdown for the fuel tank it does not show any vent lines.
View attachment kioti fuel tank.pdf

DieselBound · Oct 13, 2020

Late to the party. After reading the original post I thought right away to check the fuel cap!

I had a problem with my original locking cap allowing water into my tank. Didn't find this out until my dealer sent me a new cap after I tossed in a rant (in an email of another issue) about how cheesy the original one was.

kspring61 · Nov 26, 2020

Second Update: Been gone for awhile due to MIL passing away, but finally got back home and my new cap was here. Tried it out and still have an issue with losing power after 1/2 - 1 hour of use. So I drained the tank and flushed it out. Good fuel flow from tank. Took the fuel pump off and pulled the plate to inspect for stuck debris or a tear in the diaphragms. Everything looked OK, but now when I start it the problem is worse. With tractor sitting and just running the rpm's up to 2000 it starts to falter after about 20 seconds and then just dies. Give it a few seconds and starts right up. So I took the fuel line off where it goes into the fuel filter and cranked the engine, hardly anything came out. Is this a valid test to see if the fuel pump is pumping correctly??

Thanks

jimglassford · Nov 26, 2020

That test tells you have little fuel flow. The pump could be fine and there is a restriction upstream. Take both air lines off and see if you can blow air into the outlet.

TnAndy · Nov 27, 2020

ruffdog said:
Bugs are good ones to block tank outlets. First, they may crawl up into your unfiltered nozzle opening and die there. Then, the next time you fill, you deposit Mr. bug right into your tank. That is why I at least shake out the nozzle before I insert it in the filler hole.

THIS is what happened to me twice with my Yanmar. Dirtdaubbers ! Even though your fuel tank nozzle is in that bracket to keep rain out (I assume), they have the ability to seek out the smallest hole/crack and enter it looking for a place to build their nests. They get in the end of the fuel filler nozzle, die, and when you fill the tractor tank, you hose it right into the tank. I finally solved that particular issue by using a TIGHT plastic cap off a spray paint can over the end of my filler nozzle.

The other thing I did is fix the stupid tank outlet. Yours is probably like mine.....1/4" plastic fitting coming out of a plastic fuel tank on the tractor. Doesn't take much of an obstruction to float around in the tank, block the hole and shut your fuel down to the point the tractor starves for fuel.

Read here for my fix: https://www.tractorbynet.com/forums/yanmar-new/384506-well-finally-fixed-i-hope.html

kspring61 · Nov 27, 2020

jimglassford said:
That test tells you have little fuel flow. The pump could be fine and there is a restriction upstream. Take both air lines off and see if you can blow air into the outlet.

TnAndy said:
THIS is what happened to me twice with my Yanmar. Dirtdaubbers ! Even though your fuel tank nozzle is in that bracket to keep rain out (I assume), they have the ability to seek out the smallest hole/crack and enter it looking for a place to build their nests. They get in the end of the fuel filler nozzle, die, and when you fill the tractor tank, you hose it right into the tank. I finally solved that particular issue by using a TIGHT plastic cap off a spray paint can over the end of my filler nozzle.

The other thing I did is fix the stupid tank outlet. Yours is probably like mine.....1/4" plastic fitting coming out of a plastic fuel tank on the tractor. Doesn't take much of an obstruction to float around in the tank, block the hole and shut your fuel down to the point the tractor starves for fuel.

Read here for my fix: https://www.tractorbynet.com/forums/yanmar-new/384506-well-finally-fixed-i-hope.html

After flushing the tank I checked the fuel flow to the pump, it was fine. Checked it again when I saw the pump outlet flow was not good and still had good gravity feed flow from tank.