Repairs tractor shuts down after 25 minutes and difficult to restart

[jneknez]

I have tried loosening the cap, completely removing and cleaning the vent hole. I don't think there is a pump. The fuel line runs from the bottom of the tank into the filter then into the carb.
I will try cranking and seeing how much fuel is coming through the line then try it again when I have this condition. I'd be surprised if it was different though.
Thanks for the ideas.

 

[ILENGINE]

I went back on read your original post and noticed that they installed a new fuel filter. Which fuel filter did they install. There has been cases where the fuel filter for a fuel pump system was used on a gravity system, and would restrict flow and cause running problems.

 

[jneknez]

They said they installed OEM parts the bill says RT 1358 1/4-5/16 filter. I thought of buying another and replacing just to rule it out but it would be odd behavior for it to run properly for nearly a half hour then cut out don't you think? This problem is very consistent now each time I run it...then it runs smooth again once it sits a while. I've also adjusted the mixture slightly in both directions with no change.

 

[ILENGINE]

That part number is for a Rotary aftermarket fuel filter. it crosses over to the 25 050 22-s Kohler filter which is 51 micron designed for fuel pump use only. So there may be something to the fuel filter. I would try a different filter designed for gravity flow systems. Something in the 75 micron size range.

 

[jneknez]

Thanks for checking...I think that has to be my next step. I will pick one up in the morning and run it again.

 

[bertsmobile1]

Befire you start mowing remove the fuel line and time how long it takes to to fill a cup.
When it stops new time measure how long it takes to fill the same cup.
If there is a significant difference then remove the fuel tank & clean it out.
Check the outtlet hole carefully as some times a flash of plactic from the moulding partially blocks the outlet and other times the outlet hole is not quite big enough.
Then you add debris sitting on the bottom of the tank that iss too big to flow down the line & you can get this exact situation.

 

[jneknez]

Thanks to everyone who offered advice. I finally have it figured out. Ran it again today. Timed the fuel flow while cold then the same issue presented at the same time as previously noted while running. As soon as I felt the slight hesitation again I put it in full choke and was able to run a few minutes longer. When it finally died I pulled the line from the carb and there was a trickle for 4-5 seconds then the trapped air in the filter cleared and it started flowing freely again. I reconnected to carb and it started right up. The suggested 33940 fuel filter appears to be discontinued and Sears only sells 33392 locally. I have it but am hesitant to throw it on. Looks exactly like the new one the shop installed.
My final concern is that the line coming from the bottom of the tank goes slightly uphill to rest on a bracket on the tractor then down to the filter and again slightly uphill into the carb. This has been the same flow since purchased new 6 years ago and never a problem. I'm going to shorten this line so it is a bit more direct.
Thanks again for your thoughts and assistance.

 

[bertsmobile1]

Thanks to everyone who offered advice. I finally have it figured out. Ran it again today. Timed the fuel flow while cold then the same issue presented at the same time as previously noted while running. As soon as I felt the slight hesitation again I put it in full choke and was able to run a few minutes longer. When it finally died I pulled the line from the carb and there was a trickle for 4-5 seconds then the trapped air in the filter cleared and it started flowing freely again. I reconnected to carb and it started right up. The suggested 33940 fuel filter appears to be discontinued and Sears only sells 33392 locally. I have it but am hesitant to throw it on. Looks exactly like the new one the shop installed.
My final concern is that the line coming from the bottom of the tank goes slightly uphill to rest on a bracket on the tractor then down to the filter and again slightly uphill into the carb. This has been the same flow since purchased new 6 years ago and never a problem. I'm going to shorten this line so it is a bit more direct.
Thanks again for your thoughts and assistance.

Blowing the line out to make sure it is clean is a good idea, shortening it is not. It needs some wriggle room and a fuel pump will overcome any up hills.
Pull the line to the carb off and the plug out.
Earth the plugs as far away as possible put the carb line in a reasonably bigjar with some fuel in the bottom like you are about to bleed the brakes.
crank the engine and watch what comes out.
You should get a little air at first then it should flow free & clean.
If you are geting a lot of air then the pump is sucking air & you have a hole, bad diaphragm, loose joint,