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'74 Dual Carb Bus - gas in oil?

Posted: Mon Jul 27, 2009 7:57 pm
by Birdibus
I parked my 74 westy a few months ago when it began running very badly. Colin discovered on Saturday there was a gallon of gas in the oil! You should have seen the horrid blue smoke and the blow by flying out the tailpipe!

Now there is fresh oil in the bus, and she seems to be running well enough for now. My question is, how is it that gas can get into the oil? If Colin explained, I don't recall the answer. Something about a valve stuck open?

Re: gas in oil, how's that?

Posted: Mon Jul 27, 2009 8:05 pm
by Amskeptic
Birdibus wrote:I parked my 74 westy a few months ago when it began running very badly. Colin discovered on Saturday there was a gallon of gas in the oil! You should have seen the horrid blue smoke and the blow by flying out the tailpipe!

Now there is fresh oil in the bus, and she seems to be running well enough for now. My question is, how is it that gas can get into the oil? If Colin explained, I don't recall the answer. Something about a valve stuck open?
There are two ways to contaminate the engine oil supply. One is a sticking needle valve in the carb that does not close when the float bowl fills up. The other is a sticking choke plate.

I do not remember if I wrote down the test you need to make should this symptom pop up again. As I remember it, if the bus starts running poorly again on you, pull over, shut it off, go to the air filter connections and pull them up off the tops of the carburetors and feel for the choke plates. They should be sticking pretty much straight up and down on a warm engine. If one is closed, that is the problem. You had some sticky-ish choke plates on both cars. Needle valves are trickier. I had a brand new crap needle valve drain my gas tank into the crankcase, the engine would not turn over because of hydrostatic lock. We did talk about it. I asked you to let me know if the oil smoke fragrance clears up, because of all that oil that dumped into the heat exchanger and muffler. If it does not clear up after 100 miles, then ring damage may have occurred from gas dilution.
Colin

Posted: Mon Jul 27, 2009 9:27 pm
by skin daddio
any chance a messed up fuel pump could cause it? i have a 65 standard dual port w/ empi carb in the yard and i thought gas got in because of the pump was knocked out loaded.

Posted: Mon Jul 27, 2009 9:55 pm
by Amskeptic
skin daddio wrote:any chance a messed up fuel pump could cause it? i have a 65 standard dual port w/ empi carb in the yard and i thought gas got in because of the pump was knocked out loaded.
Not in this instance. . . though "knocked out loaded" is bit hard to interpret.
Colin

Posted: Thu Jul 30, 2009 1:12 pm
by Birdibus
Left carb
Image

Right carb
Image

March 20, 2009, I sent you a PM. Part of our exchange:
The 74 bus died this morning. Sounds really bad. Hopefully it is just a loose float in the carb, but it sounds dire. cataclysmic.

there was a backfire, then I lost power. I found a loose boot on the right side and reattached it. the left boot was ok. didn't help much. anything else to check?
What made you think of a loose float?

Colin
I thought of a loose float because it happened once before and the symptoms were similar. I haven't looked yet.

It runs, barely, on one or two cylinders. It ran rough when I started this morning. I let it idle until all 4 cylinders kicked in and it seemed to smooth out. At the end of the block I stopped, then thought I heard it pop when I revved to pull forward. Engine died. Stared again, and it was VERY rough, like only one cylinder. I checked the L-boots and reset the right side. Was able to start it, but it was still rough. I made a U turn and rolled downhill most of the way home. I pulled to 71 out of the carport, and was able to drive the 74 up the driveway, but roughly.

Oil is full.
Turn on the ignition but not the engine. Pull the wire to the cut-off jet on the right carb. Touch the wire terminal to the spade on the cut-off and see if it clicks. Put it back on. Now try the left side. Do they both click nicely? Are the wires in good condition leading to the #15 (+) terminal on the coil? It sounds like a cut-off solenoid. Notta big deal.
If the symptoms remain after testing the electrical connection, you can pull the cut-off and clean it and the hole it came out of with spray GumOut. Lemmee know. This sounds like the classic dual carb bus solenoid dance.
Do you think there was gas in the oil at this point? or afterwards?

Posted: Thu Jul 30, 2009 7:31 pm
by Birdibus
More bad news. I placed a fresh sheet of cardboard under the bus, then realized I need to warm the engine before changing the oil. I drove a block and when I came home, I noticed fresh spots on the cardboard. Gas! I saw a fresh drip, and found the source to be this. Please name it:
Image

Posted: Thu Jul 30, 2009 8:14 pm
by werksberg
Bad fuel pump or leaky hoses....

Posted: Thu Jul 30, 2009 8:33 pm
by Elwood
Yicks :pukeleft: Black Widow webs. but beside that Birdi I agree with Werks, bad line leaking and maybe the pump. I say replace all.

Posted: Thu Jul 30, 2009 8:42 pm
by skin daddio
i'd pull the dipstick and see if its thinned with gas, then smell for same.

Posted: Thu Jul 30, 2009 9:11 pm
by Elwood
Yes forget the pump replacement like skin says - but the line is leakin forsure.

Posted: Thu Jul 30, 2009 10:36 pm
by werksberg
The fuel pump diapham might also be leaking (pumping) fuel into engine case too.

I'd say replace the fuel pump and those hoses too.

But first steam or car wash the engine with engine degreaser first (but cover the dist. and carbs to prevent them getting wet.

IM me where in Inland So Ca. you are Birdibus and maybe I can drop by to help you on one of my runs to stops....

Since I see carbs.....I take it is your '71 Bus? With Generator or alternator?

Posted: Thu Jul 30, 2009 11:07 pm
by Birdibus
Hey Werksberg, the leaky fuel pump is on the 74, dual carbs. Yes, it needs more cleaning under there. Help would definitely be appreciated. This bus has been non-op most of the past 12 years. Got it running last year only to have more problems a few months (and not many miles) later. I used to drive it every day, but it's been a long time now.

So, what path does the gas take to get into the oil? Does it go in all the time or just when it runs? Yes, I smelled gas on the dipstick a couple days ago and I smell it in the oil I drained a couple of hours ago. I haven't replaced the filter and oil yet. Should I?

Does one generally look for an OG rebuilt fuel pump, or do we prefer to buy new?

Barb, I killed the spiders, I just to to get in there to collect the webs on a stick.

Posted: Fri Jul 31, 2009 6:37 am
by RSorak 71Westy
The bad fuel pump leaks fuel thru the bad diaphragm in to the crankcase, it only does it when its running.

Posted: Fri Jul 31, 2009 10:17 am
by twinfalls
Birdibus wrote: So, what path does the gas take to get into the oil? Does it go in all the time or just when it runs?
Does one generally look for an OG rebuilt fuel pump, or do we prefer to buy new?
.
On a punctured diaphgram the gas goes under it.
From there is shoud go on the floor through a small drain pipe, but it can also go into the crankcase following the pushrod that operates the pump.

It pumps gas to the oil only when the pump is running setting gas under pressure.

New pumps and repair kits for the 1974 are NLA. I was lucky to find some of the last pumps years ago.
The best would be a rebuild with a new diaph. from an old new stock kit.

Clean the mess and investigate at the pump drain tube after or while running the engine.

Posted: Fri Jul 31, 2009 10:20 am
by werksberg
I can get new fuel pumps.

The carb fuel pump "looks" like the std. type 1 fuel pump and they are cheap.

The listing for a '74 is for a FI and that one is very expensive! :pale: