Tuesday, May 5, 2009

The Great Flood...

When we last left our hapless heroes, they were struggling with a pair of flooding S.U. carbs on their 24 Hours of Lemons entry, the "Killer Bee" MBG.

I took the float lids back off to inspect and adjust the float. One look at them and I knew it was futile; The float hinges were worn beyond use. So I threw the lids and metering valves into some solvent to soak overnight.

The next day a quick trip to the local MG supplier revealed that the superior floats with an adjustable brass arm were NLA. The only version available anymore are the all plastic versions, that are non adjustable, but they do sell .015 shims to adjust the needle valve instead if needed.

I bought the floats and of course I forgot to get shims before I left.

Both the floats were a little tight around the float pin, which kept them from falling freely to let gas in. A little magic with a brass wire wheel cleaned up the pins. Working the pins them in and out of the float hinges reamed the floats so they were nice and free to open and close with gravity.

The MGB bible (IMHO) is the Haynes MGB repair manual. According to that book, the correct float height is about 1/8th of an inch, or .125. A good starting point.

The new floats come with instructions that claim anything between .062 and .187 is fine (1/16 to 3/16). Previous experience tells me that is horse puckey. At 1/16ths you'll flood around every corner, and 3/16ths it will sputter.

I set up my floats to measure them, and found the front float was at .136, and the rear was at .179. I'd prefer them to be about the same, and slightly high if possible to prevent flooding under hard cornering.

Test A) I swapped the float pins, slight improvement.

Test B) I returned the float pin and swapped floats, results were worse, further apart.

test C) I returned the floats and swapped the needle valves. MUCH worse.

Test D) I returned the needle valves, and this time swapped the floats AND float pins.

SUCCESS! Now the front was reading .152 and the rear .163. Pretty close, but they are both a bit too high, which will lower the fuel level in the chamber by a bit too much for comfort. I'll have to keep this in mind if it shows any gremlins on the road.

For now, back on the car they went, and I turned on the key for testing.

All this work resulted in MASSIVE FLOODING. Oh the fun we have.

4 year old gas was spurting EVERYWHERE, pouring right out of the carb throats! I lifted the chamber piston and gas began spewing like a geyser!


I turned off the key and scratched my head...

That does not seem right.

I troubleshot the fuel system for a while longer until those bloodthirsty mosquitoes drove me indoors. The pressure was good, not too high, not too low, started and stopped ok. The float needles were functioning, and the float level should keep the fuel level below normal if anything... yet it is still flooding. The "Generic" floats were looking MIGHTY suspect as I retired for the night.

Back to the store for a whopping $1 worth of adjustment shims I guess.

"You smell like gas" my Cute-But-To-The-Point-Spouse said. "Stay off the couch".

Well, at least I'm not sleeping on it, har-har! (Considering my antics, as she says...)

(Kitty Still Here)

Next: Oh... DUH.

Previous: It lives... IT LIVES, BWAA-HAA-HAA!!

From the beginning of this mess: The Hook... (Part 1)

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