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Interesting scenario - anyone experienced this with a stuck float?

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Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
After carb and distributor rebuild, I dialed the car in and drove it a few miles (until warm) including some freeway miles. It drove fantastic. The final touch later in the day was to swap the carb floats since the plastic ones were a bit elongated in the mounting holes. I bought new floats with the metal tangs and adjusted and mounted them.

Since then the car would run great until hot, at which point the idle would drop and lope and "poot" irregularly out of the exhaust, and the car would spit some coolant after shut-down. I also noticed that after a few minutes the fuel pump would click a few times on the restart...

After the last drive I popped the hood, and happened to feel the carbs. They were hot. Not warm, hot. Heat shield and everything is in place. Temp gauge was at "N". I also noticed wetness at the end of the fuel overflow line.

My theory is that the front carb float was sticking and dumping fuel into the front two cylinders. I would think this would serve to cool the carbs rather than heat them up, but would love some thoughts or explanations. Perhaps the misbalance of mixture between the front two and back two cylinders generated the extra heat???

(I've since swapped back to the original floats, as they were working fine, but haven't had a chance to take the car out for another long drive.)

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infinity2018 Joe T
Denver, CO, USA   USA
Carry a fire extinguisher in the car while you experiment.

Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
Have one permanently mounted. smiling smiley

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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
Assuming you readjusted the floats? You can check to see if the float needle is sealing by inverting the cover and float assembly in your hand while someone actuates the switch. Not cranking just powering up the electric pump. Of course all precautions for gasoline flowing should be followed. It sounds lie a needle and seat problem to me.

Kurt.

Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
Hi Kurt. For now I reinstalled the old floats but will try the new ones down the road again once I sort out what the iasuw is. Needles and eata didnt change.

I thought it might be vaporlock but none of the other symptoms seem to be there...car starts right up again etc...next step is to change the oil since it smells a bit gassy nd I dont want to burn my bearings.

I initially suspected my symptoms point to possible head gasket but no other symptoms are present. No gases or oil in coolant, no coolant in oil, compression is good...is it possible for the head gasket to be at fault without these telltales?

And how warm should carbs get to the touch typically?



Edited 1 time(s). Last edit at 2018-02-08 08:06 PM by Poundingsand.

Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
Kurt, ate you thinking all of the symptoms I mentioned could point to a needle and seat issue?

S1 Elan Kurt. Appley
Akron, Ia., USA   USA
In reply to # 3677763 by Poundingsand Kurt, ate you thinking all of the symptoms I mentioned could point to a needle and seat issue?

No, just the overflow and poor running. I've never felt the float bowls after running but would expect them to be cool. Hope that is just a fluke. The other problems you were having sound like float needles leaking fuel past them or float level way too high.

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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
In reply to # 3677789 by S1 Elan
In reply to # 3677763 by Poundingsand Kurt, ate you thinking all of the symptoms I mentioned could point to a needle and seat issue?

No, just the overflow and poor running. I've never felt the float bowls after running but would expect them to be cool. Hope that is just a fluke. The other problems you were having sound like float needles leaking fuel past them or float level way too high.

You know, on second thought, the gasoline can get plenty hot as it runs up along the frame rail close to the exhaust. Shielding that line is sometimes necessary to prevent vapor lock so hot float bowls should be common.

littlecars Avatar
littlecars David Bassett
Nashville, TN, USA   USA
1965 Chevrolet Corvair "Ski Team Transport SOLD!"
1965 MG Midget MkII "Buffoon"
1966 MG Midget MkII "Swiss Cheese"
1970 Triumph Spitfire MkIII "Tamara's Turd... SOLD!!!"    & more
Peer do you have the original 1967 style carbs (what are the AUD #s?) with the funky little tin flap/breather mounted below the fuel entry into each bowl? I read somewhere when the temperature under the hood reaches a certain level, or during aggressive driving, the tiny hole will allow gas to drip onto the top of the bowl and flow onto the heat shield. Not sure what the fix would be. Car won't run well if the temperature of the fuel rises to dangerous levels. In the stock photo below, a pair of silver "breathers" are shown near the pair of float valves. Photo says for 1969-71 but I believe earlier cars had these too.



Edited 3 time(s). Last edit at 2018-02-09 12:06 PM by littlecars.

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Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
David, I have AUD 404s, recently rebuilt. Aside from the symptoms I mentioned, the car was leaking more oil than usual after shutdown (but not during driving). This adds to my theory that the carb was dumping fuel into the cylinders - possibly thinning the oil and promoting the extra dripping...I don't believe they have the little flaps. I have an extra hose nipple, and have run a drain hose forward and down near the driver's side headlight.

hoggie Avatar
hoggie Mike Hogan
Oklahoma City, OK, USA   USA
by the way, after a run, do you smell gas and the top of the one of the carbs is wet ? If so, most likely, your needle/seats are not closing completely (or a float has fuel in it). Either need to be cleaned or replaced. Also if you have replaced the fuel pump, be sure your not exceeding 4psi. Doesn't take but a small bit of grit in the line to cause them to leak and flood the carb. One of the most common issues I've found over the years. I have a metal inline fuel filter mounted on the carb fuel line hose. I took it off one for a period of time, and within a few weeks I started to have some flooding. Don't know where it picked up the debris because the tank and lines were clean. Put the filter back on and problem solved. Those needles and seats are just too easy to foul up.

Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
I will be checking them again in the morning. Do you think my symptoms might reflect a stuck float and flooding the running engine? The symptoms don't seem typical of flooding. - hard to restart etc...but I do smell fuel and see wetness on the overflow. But the engine continues to run albeit poorly.



Edited 1 time(s). Last edit at 2018-02-10 12:13 AM by Poundingsand.

Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
Test drove the car about 20 miles today after a quick oil change and checking mixture and carb synch. The car ran much better even with temp needle almost at "N". I was so intent on watching oil pressure that it took me a while to realize it was idling quite nicely warm. Today wasn't as warm as the last drive but still good signs.

The bad news is that I still lost some coolant on the drive (overflow onto the frame rail but no noticeable drop in level in radiator) and the fuel overflow was wet. But no coolant overflow after shutdown... Now I'm questioning the routing of my hoses as well as the integrity of my radiator cap. So I have questions:

1) how far should you have to push the radiator cap down to twist it shut. Mine makes contact with the inside of the radiator and moves imperceptibly when I push down with my palm to twist it shut.

2) am I possibly overfilled on coolant? Pic attached

3) are my hoses from the carb routed correctly? Another pic included!

I'm curious as to the fuel path through the lid of the float...



Edited 1 time(s). Last edit at 2018-02-10 06:55 PM by Poundingsand.


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S1 Elan Kurt. Appley
Akron, Ia., USA   USA
Peer, are you sure you have the correct radiator cap? The early radiator like yours uses a deeper cap than is standard at most parts stores. A quick measurement of your cap and where it is supposed to seal will tell the tale. Incorrect cap will lose coolant constantly but loosing coolant will occur in the early radiators if they are filled right to the top anyway. If you can see your coolant in the radiator its probably full enough.

Kurt.

Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
Hi Kurt, its made in England and rated to 7 lb. Should it just sit on the lip in the radiator or require some compression of the spring when locking it?

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