Kubota MX5800 Vapor Lock

[crokett]

I borrowed an MX5800 this morning. I didn't check the fuel level visually in the tank, evidently the gauge is off. The tractor died, I checked the tank, no fuel. I've put fuel back in. It turns over, but won't start. I'm pretty sure its in vapor lock. I know I need to purge the air out of the lines but I'm not sure what procedure to follow for this specific model. I've done some looking online, but it seems to be model specific. I'm hoping someone has pictures. I'd like to fix it myself just to learn how it's done.

 

[crokett]

It's fixed. About 15 years ago I helped with a a fuel line purge after some one else ran it dry on a John Deere that then was probably 20 years old. Today I called a friend who called another friend who said with the newer tractors just keep cranking until they start. I said what if I run the battery down. he said charge it back up and keep trying. Anyway, it started after 15 or 20 seconds of cranking.

 

[FatTire]

There is a little bleed valve before the injectors (after the lift pump) but it sounds like you didn't even need it.

 

[Grouse09]

Gives me courage to change my fuel filter. I wanted to change it when I got lower than a half a tank, but have been putting off doing it in fear of the vapor lock potential.

 

[KennyV]

I know you can get air in your injector system and that will stop high pressure fuel delivery... But what are you doing to diesel fuel to cause it to "vapor lock"? short of extreme temperature and very low vacuum I do not think you can get diesel to vaporize.

 

[bdhsfz6]

The MX5800, like many newer Kubotas, has an electric fuel pump. You can hear it clicking when you turn on the ignition. That means fuel pressure is building even before the starter cranks the engine. The result is the air in the system is purged more quickly during cranking and often needs no bleeding. Use caution though since prolonged cranking can overheat the starter.

 

[Steve1300]

I know you can get air in your injector system and that will stop high pressure fuel delivery... But what are you doing to diesel fuel to cause it to "vapor lock"? short of extreme temperature and very low vacuum I do not think you can get diesel to vaporize.

I think the term "vapor lock" as the OP used is a reference to having no prime in the fuel pump. It isn't the same as a "vapor lock" caused by fuel vaporizing in the fuel lines.