MGB & GT Forum

Let's see...how does it go? "I'm madder than a wet hen"?

Yeah...kinda that.

So...I get up this morning. Sun shining, quiet...everyone sleeping. I push the car out into the sun and stretch the tonneau then decide I'll run into town and fill up early. Planned on taking a drive up to High Cliff state park...and around Lake Winnebago.

Car ran great...

So...I go to my regular station. I go there because everything they have is non-eth...but at just over regular prices. I get to the pump and decide to fill it with 93 Octane...just to see what the difference is. Normally...I don't do this because of the propensity for the higher grade to sit in tanks longer and having it go stale. However, this station is very busy. Like I said...all the gas is non-eth, so there's a LOT of people in and out of there every day and it's only an 8 pump station.

I pull out of the station and start driving home. Things are running well for about a mile then I get to a light and all of the sudden it won't hold an idle. I mean...it dies...almost. I rev it a couple of times and put it in gear. Starts sputtering and running REAL bad. I pull into a park on the way and again...as soon as I let off the throttle...it dies. No intent of idling...just pretty much a straight line to 0.

I manage to barely get it started again...and made a B-line home. I push in the clutch to round a corner...dead. Put it in gear, pop the clutch and it sputters to life. As long as I kept the RPM's up it ran at 55 for the 7 miles but again...after I let off the gas, I coasted into the garage. I let it sit for awhile...and now it won't even fire.

I tested everything I could think of. It's got spark(verified by tester), compression(125 straight across the board) and the fuel pump is clicking without hesitation after I pulled the line off the front carb.

I swapped coils with my known good spare, pulled the cap/rotor...checked the points as well.

I pulled the valve cover, checked all the clearances and operating order of the valve train...all looks to be good to go there as well.

I removed the carbs, tipped them over and pulled the float bowls off to drain the gas as well. Nice and clean, no obstructions.

Now...while I had the rear carb off and upside down, I was careful to look for signs of the float bowl needle being stuck in the closed position. One of them fell right down...the other took a little tap but didn't appear too stuck up in the jet, however it took a slight tap to get it to drop. I don't know if it's just because I had it at an odd angle...or if IT could be the problem.

The plugs looked good...save for #3. It was pretty black and sooty. Also...I took a Q-tip and as I was rotating the engine over by hand, poked it though the plug holes on every cylinder. #'s 1&4 piston domes were dry. #'s 2&3 were wet. I don't get that one at all...

So...Bad gas...or stuck float bowl needle. That's where I'm at.

Anyone else have an experience with bad gas that's similar? I'm NOT looking forward to draining 12 gallons of gas, purging the lines etc...

Thanks in advance.

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"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

"Who do you think you are? I am."...Pete Weber

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...



Edited 3 time(s). Last edit at 2015-04-28 09:52 AM by HiPowerShooter.

JEB,

All signs point to a bad load of fuel. Go to an auto parts store and get two bottles of Dry Gas or other brand of fuel additive whose label says it disperses water in the fuel. Gasoline and water don't mix, and I suspect if you take a sample from the fuel line at the carb into a clear glass jar you'll see clear stratification of two separate liquids. The difference is quite obvious. If you're not sure, then there's probably no water present, but you can confirm by just adding a couple ounces of water to the bottle and you'll see the difference.

Dry Gas or similar changes the chemistry of the fuel, allowing the water to mix with it and be dispersed throughout the fuel load, and be burned off, harmlessly and unnoticed. So if you detect water, add a bottle of Dry Gas to this, and the next, tankful of fuel, and your problem should disappear...

Dick

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Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

I'm just real leery of installing the carbs, filling the bowls/lines again with a load of bad fuel. Right now, with the carbs off, I was able to put a pickle jar just aft of the radiator when I tested the pump. I allowed it to push about a quart through the system so I could look at it. Didn't smell obviously varnished...but I didn't let it sit long enough to see if it's separating either. Maybe I'll run out and do that.

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"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

"Who do you think you are? I am."...Pete Weber

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...

Crank the idle adjustment screws in a bit and see if the problem is solved. You may have fuel that just won't idle at 650rpm. Try sitting in the car with your foot on the pedal at 1000rpm. If it doesn't die, that's all it is. :-) Basil

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Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
1958 MGA Coupe (Racecar)
1959 MGA Coupe (unrestored)
1960 MGA Coupe (unrestored)
1960 MGA Roadster (Driver)
MKIII Elva Courier (E1056)
1967 427 Cobra
1972 Alfa Romeo Montreal
A coupla late MGBs
1960 Austin Healy BN7
More Cars than Brains

One more thing to add to my emergency kit. Not complaining - grateful.

Called Canadian Tire, they don't have "Dry Gas", but have an STP product, but salesperson said it's really just Methyl Hydrate.

Is this the case, and how much would one add to a full tank?

Doing Gary's Run in 3 weeks, and want to fix problems on road.

Just read the label to see if it mentions getting rid of water in the fuel. You don't want octane booster, you want a product that allows water to dissipate throughout the fuel load. Typically it's a bottle per tankful...

Dick

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Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

I can't even start it...It fired once, after a couple of tries prior to me pulling the carbs...other than that. Nada.

When I pulled over at the park, I did advance the idle adjustment screws approx. 1/4 rev. No change. No idle.

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"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

"Who do you think you are? I am."...Pete Weber

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...

I just went out an pumped about 4 cups of gas into a clear jar. I'm letting it set for a few minutes to look for signs of separation. Nothing stood out at first glance. The fuel doesn't seem to have such a strong odor in comparison to the can of gas I just got for my lawn implements. When I sniff it...I don't get that overwhelming "whoa" odor it seems. Seems less volatile in a way. Maybe I'll do a burn test and see what it's burning at as well.

---

"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

"Who do you think you are? I am."...Pete Weber

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...

It still sounds like water in the fuel to me, but once you have it back together you could try swapping in a different condenser...

Dick

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Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

Based on smell or your burn test (if you try that) does it seem like it could be mixed with diesel? Can you empty your float bowls and fill them with known good gas? Then start it and see if it runs okay for a few minutes and then goes sour again after it is getting fed from the tank.

Charley

Take the air cleaners off and try, a vent might be blocked. If that doesn't work, leave the air cleaners off, manually raise each carb piston, and shoot in a healthy dose of WD40. Now start it. If it tries to fiure on WD40 - it's a fuel problem. If not, it's probably electrical :-)

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Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
1958 MGA Coupe (Racecar)
1959 MGA Coupe (unrestored)
1960 MGA Coupe (unrestored)
1960 MGA Roadster (Driver)
MKIII Elva Courier (E1056)
1967 427 Cobra
1972 Alfa Romeo Montreal
A coupla late MGBs
1960 Austin Healy BN7
More Cars than Brains

JEB,
You should remember the story of the pilot who did his fuel checks, saw no separation and took off only to have engine failure at 1000', Turns out that he'd drained pure water from both wings and there was more left behind. That's why we also use the smell test, if it doesn't smell like fuel......it isn't.

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Chris Howells

1968 MGB Purchased already dis-assembled but which is largely back together so I'm a lot less ignorant.

And color.

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"It is a mistake to try to look too far ahead. The chain of destiny can only be grasped one link at a time."
Sir Winston Churchill
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"It all starts in your mind's eye, then it goes to your heart
and finally to your very soul."
G.S.George PHD

A quick and cheap water disperser is metho, (denatured alcohol). A pint in the tank should do.

Herb

Ok...I'm thinking it's NOT the fuel. I see no signs of water whatsoever...it's nice and clear with just a tinge of yellow. No real solid particulate at the bottom of the jar after the shake/swirl test I remember doing with JP5(oh...We got gas in Australia once on deployment, the fuel guy was amazed at how clear it was...the best he'd ever seen!). I had the carbs out and blew air though all the vents as well. I'm going to put it all back together, add some HEET to it for good measure, allow the pump to pass a few cups through the filter, reconnect the line and light the fire. See what I get. I will still do a burn test...and try the IR gun on it to see if I can find a discernable diff in temp. Thanks for the help guys...I'll let you know.

Playing Devils' advocate here...so does a flaky condenser fit the description as well??

---

"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

"Who do you think you are? I am."...Pete Weber

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...