Won't stay running unless fully aired up.

[gumpy]

So to shut down you're reaching in there and pushing the lever right now?

No. It shut down just fine. It wasn't running on startup after 30 lbs. He's prevented the shutdown cylinder from activating the rack fuel shutoff lever until it gets fully aired up, and then
removing the wire he used to hold it. After it's aired up, it starts normally, runs normally, and shuts down normally.

[eagle19952]

sounds like it's wired backwards...so that the coil is not closed on the key switch or a bad relay.

[gumpy]

sounds like it's wired backwards...so that the coil is not closed on the key switch or a bad relay.

No. It's not wired backwards. It's either a bad Skinner valve (most likely), or it's a bad sensor in the shutdown system.

[eagle19952]

No. It's not wired backwards. It's either a bad Skinner valve (most likely), or it's a bad sensor in the shutdown system.

time will tell. i did say bad relay. and backwards meaning improperly also...

[gumpy]

time will tell. i did say bad relay. and backwards meaning improperly also...

Well, here's the thing. He was driving it down the road just fine one day, and the next morning, it wouldn't stay running. The difference was he pulled over for the night. Now, I'm not saying some road gremlin didn't get in there while he was traveling and rewire that Skinner, but I think it's unlikely. I suppose there's a scenario where a broken, or breaking wire could cause the symptoms. I don't think they'd necessarily be repeatable as his are.

Not completely discounting the bad relay idea, either, since there is one in the shutdown system, but I can't come up with any scenario where a bad relay would produce the symptoms he's experiencing. If the relay were stuck on startup, it might certainly cause it to shutdown when it airs up to 30 psi. However, there's not a solution for the problem going away when he gets fully aired up. If the relay were stuck, it would still be stuck at 120 psi, also, causing a shutdown.

Considering he said they washed the motor just before leaving FL, I'm sticking with the moisture in the Skinner valve theory, which is causing it to stick open, or partially open, until enough air pressure builds in the system to force it to close.

[DoubleEagle]

Considering he said they washed the motor just before leaving FL, I'm sticking with the moisture in the Skinner valve theory, which is causing it to stick open, or partially open, until enough air pressure builds in the system to force it to close.

Excellent logic, and given the history of Skinner Valves and their ability to cause grief, I agree totally.

[robertglines1]

Could you pull air line off and drop 2or3 drops of air tool oil in it/or line then reconnect? I have done this in other parts of air system with good results. I agree it sure functioned until  it sit for awhile.