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I'll get to the weird setup supplying gas in a minute, but let's start at the beginning. Yesterday was a Saturday, and I had just started diagnosing the fuel system. John Zimmerman had seen Part 1, and called to see what was going on. I asked if he could stop by for a few minutes and bring his lawnmower gas can. That few minutes turned into four hours, but whatever...
The work on Saturday absolutely required two people. John first stood at the front as I turned over the engine. I had put one spark plug on the end of its wire, and he watched for a spark. It was great, so I reinstalled the plugs and we dripped a few drops of gas into the twin carburetors and tried to start it. It fired immediately, but would not stay running.
We ascertained that the fuel pump was indeed delivering gas. I was confused in Part 1 by the way the pump works - it is an "on-demand" pump, so it only runs when fuel pressure drops to a certain level. Multiple tries showed the car would readily run on gas dripped into the carbs, but would not continue to run.
We reasoned that the likely cause was the needle valves in the carbs being glued shut by gasoline that had sat for five years. A quick Internet check on my phone confirmed that the carbs had to be removed to access the floats and needle valves. Here's an exploded view - click to expand:
Basically, on each carb I needed to remove cover #29, then, remove screw #26 to allow me to remove float #25, and then I could lift out the needle valve, #24. Interestingly enough, in this diagram the needle valve is shown upside down - the point should go up.
The carbs have to be removed as a pair, and then can be separated from the linkage. Here's the engine with one carb removed, and the other ready to go. Sorry about the finger in the picture - I seem to do that a lot.
Once we had the carb on the bench, John held it while I removed the cover and exposed the float:
All that gunk on the float is residue from 53 years of gasoline going through these carbs. Removing the float uncovered the stuck needle valve:
We freed up the valves, and also freed up the choke mechanism, which was frozen solid on both carbs. We then reassembled everything, and gave it a try. It would still run on gas dripped into the carb, and it would "hit" but not run on the gas in the carbs. We called it a halt for the day - I really appreciated that John hung in there for four hours as we dealt with this! We both really stank of old gas by the time we were done.
I later sent the picture above to Phil Oles, who in addition to being a fine machinist is a retired chemist. He confirmed that the old gas had probably gummed, and required some strong solvent. Exploring several possibilities, we settled on "starter fluid", the spray that you use on carbureted engines to get them to fire in extreme circumstances. Phil impressed me by immediately identifying that substance as diethyl ether.
So, today I went to Autozone and picked up some supplies: a can of starting fluid (I checked the back right away, and sure enough, diethyl ether), a quart of 20W50 oil, a long-neck funnel with a sealed top, and several feet of 1/4" fuel hose and matching hose clamps. The oil was for the carbs - those SU carbs use oil as a damping fluid, and a good bit leaked out when we working on them. The Internet claimed that straight 20W was used back in the day, but that's hard to find now, and lots of folks claimed better results using a multi-viscosity oil like 20W50.
I also stopped by the drug store, and picked up a syringe designed to give babies medicine. It was only a couple of bucks, and the perfect tool to get the oil back into those carbs.
When I got back to Grant St. I started by testing with using the starter fluid with the carbs still hooked to the gas tank. I mean, hope springs eternal, right? But it just wouldn't run beyond the second or two that the starter fluid carried it.
I started some lathe work. See, I needed a way to marry that funnel to the fuel hose. I used a 3/4" Delrin rod I picked up at Cabin Fever a couple of years ago. Delrin is a very dense plastic, and definitely impervious to gasoline. I drilled the back side 15/32" to fit the nose of the funnel, drilled through 3/16", and then turned a nose to fit the fuel hose,:
I plugged the MG's fuel line to the carb with a 1/4" screw so it wouldn't spew gas while testing, and then put together this rig to supply fresh gas to the carbs:
Here's a closeup of that Delrin adapter in place - it worked perfectly:
Once all that was done, I had to do a little work to the choke mechanism so it could be used, and then put some gas in the funnel, sprayed a little more starter fluid for luck, and gave it a try. The result was the video at the opening - it runs!
So, here's what's next:
1. Before doing anything else, I'm going to install the big wheels on my EZCarlift and rotate the car 180 degrees. Right now, the exhaust is right in the center of the shop, and that test really stank things up! I'll make it so the exhaust goes out the overhead door. The car runs, but required some heavy choke to do so. Probably, that means the jets are still partially clogged with old gas. I'll need to run it in with gas with fuel cleaner additive to try to flush the carbs. Probably will do that from the temporary gas supply. I hope the carbs don't require a rebuild kit - that costs $160 for both carbs.
2. Sadly, the fuel tank must be drained, the entire fuel system cleaned, and some fresh gas put in. A nasty job, but I actually expected it when I signed up for this gig. Five years is a long time for gasoline. Modern gas with ethanol sours in about six months.
3. The clutch hydraulics need refilling and bleeding, at least. If it's a slow leak, I'll leave it for the next guy to rebuild, but the car can't be driven until that's working again.
4. I'm not interested in a test drive until I carefully go over the entire braking system, including flushing the fluid and rebleeding. Fortunately, I have a vacuum bleeder, so it's not a big deal.
5. All the lights (especially brakes) and other electrics need to be evaluated before a test drive also.
6. I'm gonna change the oil and filter - this little guy deserves that!
7. John is eager to do some detailing work on this MG. The interior needs a serious cleaning, and the paint also. He thinks he can bring up a really good shine, which will look very interesting against the rust holes...
8. I'm in the market for a shop camera. Taking those pictures above really slimed my phone! It also made my phone's belt case smell like gas. Fortunately, I had a spare case to use while this one airs out. I'll get a cable release also, so I can take pictures without touching the camera.
The rust issue remains the big question mark. The car is definitely flexible. On the lift, if you open the driver's side door, it won't close again until you put the car back on its wheels. That led to a very funny scene that I managed not to photograph: John climbing over the door into the car while we were doing initial testing. Neither he nor I are as young as we once were!
The repair panels to fix the sills and fenders cost around $2000 - I checked. That's the tip of the iceberg, since I'm not qualified to weld them in. I do have a mental picture of a welded X-brace under the car that will make it safe and stable while leaving the rust alone. I doubt I'll go that far.
I believe you've duplicated the carburetor that Henry Ford used on his first engine. It was a drip style, without using Delrin, of coursee.
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