1974 Westy - An Exercise

[whc03grady]

Here is a problem that came and went for me this weekend, and I thought it might prove to be an interesting troubleshooting exercise for those so inclined.

Bus: 1974 Westy, engine modified w/ 009 and a Weber Progressive.

Conditions: very cold (sub-zero) with intermittent snow, ca. 4000'.

Indications: after a cold night, the bus turned over very slowly, needing a jump to start. Bus ran well afterwards, until dying while slowing down to pull into a convenience store. Got the bus running again by dumping the clutch. Upon trying to leave convenience store, bus turns over but will not start. Suspecting battery, it is replaced whereupon bus turns over much more quickly but still will not start. Checked for and found spark at coil and plugs. Points opening and closing. Checked for and found fuel coming into carburetor.

We figured it out (with help from the tow truck guy who took us to his shop) and got it running.

Exercise: Can you tell me what the problem/s was? It was a one-two punch. There is a hint below.












Hint: stupid exposed Weber air filter was pretty dirty.

[vwlover77]

Well, I know the Weber carb has no provision for heating itself, and temps were very cold.

My guess is you removed the air filter to have a look and found your carb clogged with ice.

[whc03grady]

Not quite.

[RSorak 71Westy]

stuck choke combined w/ dirty air filter = flooded

[Amskeptic]

Here is a problem that came and went for me this weekend, and I thought it might prove to be an interesting troubleshooting exercise for those so inclined.

Bus: engine modified w/ 009 and a Weber Progressive.
very cold 4000'.
turned over very slowly,
ran well afterwards,

OK, here is a punky battery but easy fire-up suggests that the carburetor choked OK. Dirty air filter may have been helping in this instance.

until dying while slowing down
Got the bus running again by dumping the clutch.
trying to leave turns over but will not start.

Dying while slowing down suggests that choke has opened up but preheat is not working, why would it, you don't have one. Battery is still punk.

Suspecting battery, replaced still will not start.
found spark at coil and plugs.
fuel coming into carburetor.

With cold intake runners, your fuel is liquid by the time it reaches the combustion chambers. Now a dirty air filter will promote flooding. A fresh battery will help both the spark required to overcome lots of liquid and the cranking required to get some vapor to reach combustion chambers.

In that instance, I would pull the air filter, pump the gas a few times for some accelerator pump fuel vapor, then hold the accelerator to the floor for air and crank away. (warning, do not ever start a engine without the air filter on for danger of backfire that could ignite the carb, unless you promise yourself to keep cranking through such a thing, this will help suck the fire back down.

Either way, the factory choke/air preheat can't be beat, that's my story and I'm sticking to it.
Colin

[whc03grady]

Answer:
In the shop with the air filter off, the bus coughed to life, and steadily began to run more smoothly. The thingie that the air filter sits on was full of water, water that had been ingested as snow. The water/gas mixture being less than ideal for combustion was enough, along with the too-dirty air filter, to disallow a start. Ludwig couldn't get enough air to burn the watery gas.

Of course the center mount's lack of ability to keep the fuel vaporized in cold weather very likely acerbated to the problem, but I think it was the one-two punch of water and dirty air filter that knocked Ludwig out.

[Amskeptic]

Answer:
In the shop with the air filter off, the bus coughed to life, and steadily began to run more smoothly. The thingie that the air filter sits on was full of water, water that had been ingested as snow. The water/gas mixture being less than ideal for combustion was enough, along with the too-dirty air filter, to disallow a start. Ludwig couldn't get enough air to burn the watery gas.

Of course the center mount's lack of ability to keep the fuel vaporized in cold weather very likely acerbated to the problem, but I think it was the one-two punch of water and dirty air filter that knocked Ludwig out.

Water? Snow? Way in the center of the engine atop the engine itself?
Did you have drifts in the battery trays? Poor car.
Colin

[whc03grady]

Well, it was snowing that really fine snow, and it was reeeeeeeeeally cold, so I suspect the snow entering the scoops survived as snow long enough to get to the air filter. And I am ashamed to admit that while Ludwig has an intact engine-to-engine bay seal, there is some, ah, rust that allows more than a little of the environment inside.

[Amskeptic]

Well, it was snowing that really fine snow, and it was reeeeeeeeeally cold, so I suspect the snow entering the scoops survived as snow long enough to get to the air filter. And I am ashamed to admit that while Ludwig has an intact engine-to-engine bay seal, there is some, ah, rust that allows more than a little of the environment inside.

I am sure that I will be able to see for myself exactly how snow gets onto your air filter when I stop by in June.
Colin

[whc03grady]

With any luck when you stop by in June we'll be installing my yet-to-be-rebuilt stock Solexes and won't have to worry about this Weber crap ever again.
The weather, that could go either way

[chitwnvw]

I was planning on a skiing adventure when I am in Missoula this next June. Mitch said that was the time to come. Yep, June. Big time snow. Yep, Melissa promised.