Won't stay running unless fully aired up.

Scott & Heather · May 10, 2016, 04:41:43 AM

Lol Craig and I posted at the same time. That should be your issue. I'm almost sure it is....

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Dave5Cs · May 10, 2016, 07:41:12 AM

Yep and thats why I was asking where he was airing up with the shop air. Also if it was having a problem or does still from the rear then you have a stuck check valve up front also. But move the Skinner valve first to see if it is moving its shaft. If not try moving it by hand and lube it up if needed then see if it works better.
Dave5Cs

eagle19952 · May 10, 2016, 08:19:24 AM

you can certainly observe it's function without removing any screws...

buswarrior · May 10, 2016, 09:58:09 AM

But the experiment won't proceed if it shuts the engine down as 30 lbs approaches?

The sense of satisfaction of the engine finally continuing to run might be needed for morale purposes?

happy coaching!
buswarrior

DoubleEagle · May 10, 2016, 11:05:09 AM

The Skinner Valve gets my vote. It seems to be one of the most troublesome parts of any bus that has them.

eagle19952 · May 10, 2016, 02:49:36 PM

Quote from: buswarrior on May 10, 2016, 09:58:09 AM
But the experiment won't proceed if it shuts the engine down as 30 lbs approaches?

The sense of satisfaction of the engine finally continuing to run might be needed for morale purposes?

happy coaching!
buswarrior

oh...

gumpy · May 10, 2016, 03:25:32 PM

I've detailed my theory. I think it's the only plausible explanation for the symptoms indicated.

I feel others may have differing views, and may even be confusing the individual components involved.

I'm bowing out of this discussion until more information is known.

Lou, feel free to call me or email me if you need more information or guidance on how to diagnose this problem.

craig

gumpy · May 11, 2016, 04:30:01 AM

One final...

I sent this problem to a bus mechanic friend of mine who knows more about buses than any of us will ever acquire. He's the guy I trust with my bus and the guy I go to for
all problems I can't solve. He confirms my diagnosis of a bad skinner valve based on the symptoms provided.

Good luck, Lou. Email me if you need or info.

craig

eagle19952 · May 11, 2016, 10:48:47 AM

and now we wait... any updates ?

Scott & Heather · May 11, 2016, 04:24:22 PM

He won't be back at his bus until next week

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lou432 · May 11, 2016, 07:31:30 PM

Wow! And I thought my head was spinning from my career change ! Until I read the replies I didn't know what a Skinner valve was. haven't put my hands on one but thanks for the pictures and the detailed information that everyone gave me I see no problems finding it and problem solving it. Scott, Dave ,Donald ,Walter, Bus warrior and anyone that's contributed to the thread I can't remember:-) thank you very much for all of your input. I am really chomping at the bit to get back to New Hampshire now to investigate and solve this problem. If I haven't mentioned it within this thread I have decided to move the bus 200 miles to the Syracuse New York area to reside in it until I find a place but feels right for me.
Wasn't planning on going back to the New Hampshire till next weekend but it's only a three and a half hour drive from where I will be Friday evening so I may surprise attack just to put my mind at ease and figure out what's happening. Thanks again to all of you !!! I will post immediately when I return.

gumpy · May 11, 2016, 08:21:38 PM

Hmm... Thinking maybe we left out one important detail. The above photos are not of the Skinner valve, which is probably the culprit. They are of the air cylinder
that actuates the fuel shutoff. There's another right next to it that controls the fast idle.

The Skinner valves are the electric valves typically located on the firewall that control the air flow to those cylinders. I'll attach a photo.

Locate the shutoff cylinder using the above photos, and then follow the air line back to the electric valve to determine which one is the problem. It will have air lines
coming in and out (whereas the cylinder only has one coming into it), and electric wires attached to it.

DoubleEagle · May 11, 2016, 08:24:58 PM

He can't miss it now!

eagle19952 · May 11, 2016, 08:59:30 PM

Quote from: DoubleEagle on May 11, 2016, 08:24:58 PM
He can't miss it now!

the acting cylinder is called a clamping cylinder...trace/follow the airline. it ends/starts at the skinner valve

Scott & Heather · May 11, 2016, 10:42:26 PM

Clear as mud now? 😳 welcome to the madness 😩

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