JD 320 stalls when engine gets hot/warm

[nate81]

I'm noticing that when I try to mow the grass on really hot days my 320 will stall out on me after cutting for a while....if i choke it, it'll keep it going for a little longer but will eventually totally stall. It won't start back up until the engine has cooled.

I unplugged both of the wires from the spark plugs and used a screwdriver to test for spark...i did see spark in both.

I took the gas cap off and i did see a bit of dirt/grime in the little hole on the inside of the cap...i cleaned that the best i could...i havent run it since last night, so i'm not sure if cleaning the gas cap fixed it yet.

Fuel filter was changed last year I believe, or if it wasnt 2012...it was definitely late 2011.


I took the bowl off the carb....there was hardly anything in the bottom of of it and the float seemed to move up/down freely.

 

[BBO]

You may need a new gas cap. Leave it loose and try it. Change the filter again. It is cheap...
It could also be an electrical problem with the coils. Does it run smooth with normal power, or is it sputtering?
Change the spark plugs also.

But the deal with the choke does seem to indicate that it's being starved for fuel.
Stay away from fuel with Ethanol...

 

[nate81]

I'm going to the JD dealership this morning...i'll see how much a new gas cap costs. yesterday while cutting grass the mower died....i tried take the gas cap off and then i put it back on, but the mower still would not start.

I'm going to change the fuel filter today as well.

If i'm seeing a spark from the coils does that mean they are ok? It runs well with normal power, but it does not like to idle often...normally when i pull the throttle down to empty the baggers it will just die out on me and i have to restart.

Where do i get fuel that doesnt have ethanol? (edit: googled...found a mom/pop gas station that has unbranded ethanol free gas 5 miles from me)

 

[nate81]

I picked up a new gas cap, fuel filter and two new plugs (even though i just changed the plugs back in april or may)....when i took the old plugs out they looked like this http://i.imgur.com/NDAJBhv.jpg

Should the different coloring matter?

I asked the mechanic at the JD shop and he told me as long as i see spark at the wire the coils should be fine...i'm hoping he's right because the coils are about $70 each, and i'd need two!

Its raining today, i won't be able to test the mower out and see if the new plugs, gas filter, and gas cap fixed my problem.

 

[mfreund]

You only need 3 things to run, fuel, spark and compression. I think you are ok with the electrical side of the tractor running, I would try different fuel. Plugs look good to me, no worries there.

I know this is given, but I will ask do, you have enough oil in the engine?? Another Idea, check to make sure that there is nothing obstructing the air flow around the flywheel. IE mouse nest under the top shields

 

[BBO]

Another Idea, check to make sure that there is nothing obstructing the air flow around the flywheel.

And the air filter itself...

 

[nate81]

I got some seafoam and ran it through the tank...i had abotu 1/4+ tank of gas and ran a few ounces...it still stalls but at least now the thing will idle...i'm thinking the idle issue is unrelated. I feel like its overheating.

Oil level is good, checked that first thing to be sure it wasn't the low oil cutoff.

Where/what is the flywheel?

I cleaned(checked) the airfilter and washed the foam pre filter around it and reoiled that.

The book says to be sure the cooling fins are not plugged....are those kind of like heat sinks? just metal fins coming off the engine?? Because i have a liquied cooled system would I still have cooling fins? if so...where are they!? i swear this engine was installed upside down, i can't get to anything!

I'm going to fill up with ethanol free gas today with some more seafoam.

Oh...the coolant level in the off-white plastic tank (reservoir?) tank is good...but i opened the radiator this morning and it seems low to me...but there is no fill line inside the radiator...how am i supposed to know how much fluid should be in the radiator itself?

 

[nate81]

I just put two pints of water in the radiator....its not filled to almost the brim where the radiator cap goes on. Can i have too much fluid in there?

 

[JD420]

I had a 320 that was doing the same thing after it was hot it would start acting like it was running out of fuel. I found the the fuel pump was going bad. Mine had a mechanical fuel pump mounted by the carburetor. When it starts running bad remove the fuel line coming from the fuel pump going to the carburetor and put the hose in a clear container and crank the engine and observe the amount of fuel pumping out. It should squirt good solid amounts of fuel. If it just trickles out check to make sure you have a good fuel supply to the pump. It should run out of the supply hose at a good rate.

 

[nate81]

I had a 320 that was doing the same thing after it was hot it would start acting like it was running out of fuel. I found the the fuel pump was going bad. Mine had a mechanical fuel pump mounted by the carburetor. When it starts running bad remove the fuel line coming from the fuel pump going to the carburetor and put the hose in a clear container and crank the engine and observe the amount of fuel pumping out. It should squirt good solid amounts of fuel. If it just trickles out check to make sure you have a good fuel supply to the pump. It should run out of the supply hose at a good rate.

You no longer have your 320? What happened to it? how many hours did you have on it?

The coolant in my radiator seemed low to me...while the overflow tank has been good. I'm going to try running it this morning to see if it stays cooler