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MG TD TF 1500 - Low fuel level in flloat bowl

Two weeks ago I started my search for issues related to ethanol fuel. One of my first checks was to look for odd stuff in the float bowls. First place was the front float bowl. Pulled the cap off and found myself staring at a float that was sitting on the bottom of the bowl!! (BTW, there was no goo under it.) It had been a couple of weeks since Lazarus was last driven (much rain and thunderstorms). Float checked out fine. Next guess was a problematic Gross-jet. I replaced it with a new one from my spares stache.

On reassembly I dropped the new red fiber washer and had it disappear into neverland. It was simple to just reinstall the old washer.

Today I spotted the new washer on the floor of the garage. Decided to install it where it belonged. Removed the nut and lifted up the float chamber lid. Found myself staring at a float that was 'way down in the bowl. Lifted it out and found virtually no fuel in the bowl. Last time the engine had been run was Thursday, 5/17, when I did the fill up with non-ethanol.

I'm befuddled as to where the fuel has gone to. I don't detect any leakage around, or under, the carburetor.

I've been a Grose-jet fan for a lot of years. They were developed fairly close to our home in Massachusetts. Not sure if modern ones are as good as the ones that Ansel made. Maybe it's time to switch to a modern viton-tipped valve. Bud

Bud Krueger

Bud - I have Gross Jets in both our TD and MGB and have not had any problem. Have you poured some fuel in the offending float bowl and watch for the level of fuel to drain out on its own?

Are the needle valves in your carburetor worn (grove around either on the needle or valve seat)?

Also look for any cracks in the float chamber and arm. Also check the carburetor for leaks. Also check that the fiber washers have not deteriorated.

I will be following your troubleshooting since I have Gross Jets in our TD since shortly after I got the car in 1974. The same thing in our MGB.

Keep us posted.
DW DuBois

Hi David, in a few minutes I'll go out and shove a number of blue shop towels under and around the front carburetor just before I turn on the key and fill up the float bowls. Then I'll start nosing around to see if any wet spots show up. I'll let you know what I find. Bud
Bud Krueger

Had you turned the key on, activated the pump first before you checked fuel level? That would be the correct test for the filling mechanism. If that is fine, and then the fuel goes away after sitting, it has to be leaking or evaporating. George
George Butz III

No, George, I didn't do that. However, after reassembling the float bowl yesterday I did turn the key and filled the bowls. Checked by depressing the tickler.
Checked the blue towels last night, and again this morning. No sign of dampness. Then took a closer look with a flashlight and think that I may have spotted the problem. I can see dampness on top of the channel that goes from the bottom of the float bowl to the bottom of the carburetor. I have a new set of washers. I'll remount the float bowl this morning and see what happens.

Interesting to note that the aroma from non-ethanol fuel is different from that of standard fuel.

Spotted another oddity yesterday - the float bowls are not at the same height above the ground. A difference of 3/8 inch. Put a level on the intake manifold and you'll see the slope. I'm sure that it makes no difference in operation. Just an oddity. Bud
Bud Krueger


You are truly converted if you call Ethanol fuel "standard". ;-)

James Neel

Jim, I stared at the keyboard for quite a while trying to figure out what to call the stuff. I really should have put 'standard' in quotation marks.

Remounted the front float bowl with new washers and snugged the banjo bolts up good and tight. Just went out for a short spin to the grocery store. Was probably in there about ten minutes. Came out and just pulled the starter (after turning on the ignition) VROOM. No choke, No sputtering. Temperature gauge was just barely indicating. Maybe Lazarus wasn't warmed up enough yet. I'll try again after lunch with a longer trip. Bud
Bud Krueger

Hi Bud,

My car sits for long periods, and I made the mistake of filling it up some time ago. Problems abound. At one point I noticed green sediment at the bottom of the float bowls (copper oxide) and one of the inlet filters was clogged. This may be your problem. Iíve also noticed corrosion on the needles, which may cause problems. Yesterday I drained the remaining few gallons, cleaned the needles, and the difference was amazing.

J Barry

As we've been discussing vapor lock lately, especially in warm weather, the float bowls can vaporize fuel in the bowls as they cook above the hot exhaust manifold. The vapors will disappear out the vent with no trace.

As soon as the pump kicks on they'll refill quickly.

I put marine Stabil in EVERY tank of gas or fill-up. That seems to keep the gas gremlins at bay even over a prolonged lay-up over the winter.

James Neel

Fuel containing ethanol seems to pick up water over an extended period of storage. No surprise as ethanol is completely miscible with water. To prevent this creating problems I always drain the tank over winter and store the fuel in a steel jerry can (don't use polyethylene as its too permeable). Easy to do if you remove the spare plug in the bottom of the tank and replace it with a petrol resistant tap. As a result I never have any issues with fuel containing ethanol (probanly only 5% here though).
Dave H
Dave Hill

This thread was discussed between 20/05/2018 and 21/05/2018

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