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MG TD TF 1500 - Fuel Overflow Problem?

Once again I must come to the forum, hat in hand, for assistance.

I have not run or driven the TD for several months (weather too hot). It has been a joy to drive for years now. I wanted to drive it today but ran into this:

1. Went to start car. Notice the fuel pump continued a slow clicking and would not stop. Started the car and all seemed normal at first, then began rough running until my wife hollered that fuel was pouring out of the bottom (drain tube) into my litter pan. I shut the car off, but fuel continued. I caught the rest in a glass jar, but it didn't stop draining until I started the car (briefly) again. Then it stopped. Has not drained out since.

2. I pulled the rear carb float bowl cover and the bowl was completely full. I checked the Grose jet ball, and it was free, and the lever looked properly bent.

3. I checked the front float bowl, and it was empty. Float was at the very bottom, with no gas in the bowl. The Grose jet ball "appeared stuck," but when I went to change it it was free, but I changed it anyway.

4. I started the car again and it started fine, but rough running quickly ensued. I shut down and checked the front bowl again, and it had the normal level of fuel this time. Oil pressure seems a bit lower than normal, and the temp is indicating only 30C. That's weird! I guess I'm not running on all cylinders.

I don't know how to continue my troubleshooting and need all the help I can get. I have forgotten so much of what I learned when I was semi-restoring this car it's unreal.

Any and all assistance will be greatly appreciated.

L Karpman

Sounds like you sprang a leak in a float or your float stuck, and the bowl is overflowing. You may also have had a bit of debris in the float jet, holding it open. You may have a flooded engine - I would drive it for a bit.

In the worst possible scenario, you may have pumped so much gas into the cylinder that you diluted the oil, although it seems unlikely. Usually just a tap on the side of the float bowl will dislodge any debris in the jet, or free up a sticking float.

Tom Lange
MGT Repair
t lange

Sounds like the fuel bowls dried out and the float stuck to the bottom of the bowl for a bit. Chances are that everything is fine now. Take the plugs out and give them a clean..... might have fouled. Then run it again and if its smooth enough for a drive .... take 'er out.
C.R. Tyrell

Just started it again and brought it to temp. Oil pressure normal. Still rough running and backfires if revved above 3000 RPM. Checked pistons by pushing up while running and they are free. Pushing full up on the rear piston makes no change. Pushing full up on the front piston kills the engine. Car is idling very rough at 500 RPM. Two months ago it was smooth at 800 RPM, but car just sat without me doing any tampering since. Will pull the plugs and check those too. Keep the input coming.
L Karpman

Good grief. Just checked the rear float bowl and IT IS DRY. Just shut down less than 15 minutes ago. Grose jet ball is free. Turned on ignition and fuel pump did not deliver any fuel to the bowl(no clicks, no fuel flow). I thought if the bowl was empty it would. Furl pump issue perhaps, or am I just ignorant of the way it works?
L Karpman

Check the fuel flow into the rear lit - especially the filter in the float cover; it may be clogged. There is only so much it can be!

You've got fuel to the banjo bolt since the front bowl fills, so it has to be in the rear fuel entry.

Tom Lange
MGT Repair
t lange

"Check the fuel flow into the rear lit - especially the filter in the float cover; it may be clogged. There is only so much it can be!

You've got fuel to the banjo bolt since the front bowl fills, so it has to be in the rear fuel entry.

Tom Lange"

Thanks Tom. I also found the front bowl empty earlier today, but not since.

I thought I did check the flow into the rear lid (other than the lid filter), and there was none. How do I check other than turning on the ignition? With an empty bowl, and a clean lid filter, shouldn't it fill?
L Karpman

I had much the same experience two years back. Too hot to drive in Florida heat so car sat in garage over summer. When started ran rough and overflowed a float bowl. Pulled bowl covers and all seemed well but decided to clean carbs. Grose jets seemed OK. Then I noticed that when I would lift the ball with a finger nail it would stick to the seat. Even carb cleaner would not stop the sticking. When I removed the floats there was a strange green slime in the bottom of the float bowl and the center passage in the float was gummy with the same substance. New float valves and much cleaning fixed the problem. Since that time I use only straight gas with NO 10 percent alcohol. Now 2 years later car starts and runs without a problem. Good luck.

Jim Haskins 1953 TD
J. M. Haskins

Thanks Jim. A bit to dim in the garage right now, but in the AM I will pull the floats and check for the green slime or other stuff. The Grose Jet balls appear free when lifted, but I changed the front jet and will change the rear just in case. Also have to check the screens for debris or clogging.
L Karpman

The nice thing about that fuel system is that you can test it seriatim.

Remove the hose from the pump to the carb, hold it over a jar, and turn on the key to test fuel supply.

Re-attach, remove the fuel line at the rear carb banjo, test.

If OK, re-attach and remove the line at the front banjo.

You should have vigorous flow at all points. If not, look deeper. As I mentioned, the fuel lines have been known to break down internally, causing obstructions to the flow - who knows what Ethanol does!

Tom Lange
MGT Repair
t lange

Probably not the problem but have you checked the gauze filter in the fuel pump?
Max Irvine

"As I mentioned, the fuel lines have been known to break down internally, causing obstructions to the flow - who knows what Ethanol does!"

I do, the rubber dry rots from the inside out! The line looks fine from the outside, but is all cracked and gummy on the inside. Ethonal costs more, has less energy in it, drops your mileage, boils at a lower tempature (causing vapor lock) absorbes water, and destroys rubber components! What's not to love????
D. Sander

Thanks again folks.

Today, time permitting, will go as follows:

As the rear carb bowl initially overflowed and the front was later found empty, I changed the front Grose Jet. The front carb bowl now has been full each time I checked after running, so I assume OK. Later I found the rear carb bowl empty, so the simplest thing first is the change the rear jet. If no luck I will proceed with checking the system "seriatim" line by line, with checking the bowl lid screens along the way.

Yes, Ethanol is wonderful. I know what it did to my lawn mower carb to the tune of $$$.
L Karpman

It may be a good thing to budget for some new fuel lines from the pump to the carbs. I have started to use stainless steel braided teflon lined fuel line. It seems impervious to alcohol related problems. The fact is that there will be more alcohol in gasoline than less as time goes on. Everything else on the TD is brass copper or cork, and I don't think alcohol effects these.

Do not forget to use fuel stabilizer!!!
C.R. Tyrell

Success! (I hope)

Changed the rear Grose Jet and all appears to be well. Apparently they both were sticking intermittently, and I had only changed the front jet when I saw the dry front bowl. Checked all screens and they were fine. Felt dumb I had not changed the rear earlier after I saw that bowl run dry also - DUH! Car started and ran fine at idle for 15 mins, so I hope the issue is solved. Lucky I had a spare set on hand. Thanks to all for there input and expertise!!!

By the way, C.R., my fuel lines are stainless steel braided teflon. At least that's what Moss says they are :-)
L Karpman

My uncle's been making ethanol up in these hills long as I can remember - not of it has gone into gasoline. We know what ethanol (and wide mouth mayonaise jars) is for. What's not to love?

TD 25009
Near the Dark Corner, SC
J K Chapin

This thread was discussed between 01/11/2013 and 02/11/2013

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