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Triumph TR3 - Dumping Gas

Twice yesterday my TR3A dumped gas from an overflow hose just under car near the forward side the passenger door. I'm guessing it was kicked out from the float chamber overflow tubes.

What are the likely culprits on this?


Bill Stagg, 1961 TR3A
Bill Stagg

Hi Bill:
You should check the setting for your float level.If you hold the float chamber cap inverted in your hand you should be able to pass a 7/16" round bar between the cap and the fork if necessary adjust the fork so that it just clears the bar.Verify that no gas has leaked into the floats.If the floats are OK then you need new float needles and seats.


Bill - Chuck is right but it will be a lot easier to do when you get the Workshop Manual etc. that I mentioned in an earlier thread. You will be able to see the diagrams and photos of exactly what Chuck has written.

I assume that your TR is later than mine. My feed lines are braided stainless steel over rubber with brass "banjo" shaped fittings that connect to the float bowls. If you have a later TR with the plain rubber feed lines that slide on, one or more of these may be loose and/or leaking. Many TR owners buy and install tiny hose clamps to help keep them on securely.

If you have a leak along the rubber feed lines, it may be dripping continuously or maybe it only leaks when you step on the gas which torques the engine a bit on it's motor maounts which may open the leak only under these conditions.

Run the car at idle (outside) and with the engine compartment open, "blip" the throttle using the lever just in front of carb #1. Watch for leaks and let us know.

Did you know that with the hood open and the key in the dashboard "On", you can start the engine from under the hood by standing facing the carbs and with your left hand push forward on the black rubber "knob" that is at the rear of the solenoid on the firewall where the big lead feeds from the negative battery post (assuming it still is "positive ground" as it was originally).

Don Elliott, 1958 TR3A, Comm. No. TS 27489 LO
Next time mention what your Comm. No. is as they made changes to these cars all through their manufacturing years.

Don Elliott

Chuck and Don,

Thanks for the tips. I'm out of town for the next week, but I'll run this down when I get home.

I've already acquired the TR3 and SU Haynes manuals, but the shop and parts manuals are backordered at the Roadster Factory. Should have them in a couple of weeks.

The car is a '61 with commission #TS67947L.

The PO did show me the neat trick you described Don. Very handy to be able to fire the engine from under the hood.

Regards to you both,

Bill Stagg, 1961 TR3A
Bill Stagg

Bill - If your carbs are dumping gas on that side, I'd be very careful that it doesn't hit the exhaust pipe. WOOOOFFF !!!! and your TR is gone, Maybe you with it. "All the way to the Moon" as Jackie Gleason (Ralph Cramden) used to say on Saturday night TV back in the days of black and white TV.

Don elliott, 1958 TR3A
Don Elliott

Good point, Don. I don't need any extra acceleration.

"And away we go!"

Bill Stagg, 1961 TR3A
W Stagg


I finally had a chance to dive into the carburetors last night as recommended by the good folks above. The needle seat in float chamber lid was almost completely backed out of its threaded hole. A quick tightening with a wrench and, voila! LBC is back in business and not piddling petrol along the way.

By the way, my “needle” assembly actually involves a “ball bearing” arrangement to shut the valve. Is this historically accurate or a modern update?

Life is good!

Bill Stagg
1961 TR3A
Bill Stagg

I ran with the original ones in my SU carbs from 1958 to 1972. Then "Trusty" sat idle till I started the restoration in 1987. When I restored the carbs between 1987 and 1990, I put in these "new" ball valves. I can't remember the name of these new ball valve devices that go in the float bowl chamber but they are "fairly" recent. When I read just last week that the SU carb has existed since 1898, I guess that these "new" ball valves were introduced somewhere between 1900 and 1985.

Thus endeth the History lesson for today.

Don Elliott, 1958 TR3A
Don Elliott

Hi Don:I think the jets you are referring to are called Grose Jets.Some swear on them and some swear at them.I am with those who swear at them.I had some on my MG and soon abandoned them.I think the genuine SU ones are much better.

You are right Chuck. They are called Grose jets. I've done over 70,000 miles in my TR with these "new" jets and I don't think I ever had a problem during the 12 summers they have been there. I put them in and that's the last time I thought about them.

On my trip to Minnesota VTR in July, 2002, I drove almost 2000 miles, mostly on 2-lane roads, averaged 63 mph while rolling and touched 33.4 mi/gal(Imp.) or 26.7 mi/US Gal.

That's why I don't think I have a problem with these jets.

What problems did you have ?

Don Elliott, 1958 TR3A
Don Elliott

Hi Don:
When I installed the grose Jets I had a problem with flooding,a problem Grose Jets are supposed to cure.I was probably unlucky enough to get a couple with bad balls if you will pardon the phrase.

Anyone trying the trick of starting the car from under the hood should remember to check the car is not in gear, unless they can run very fast to catch it up!
n morgan

Good point, Nick. At our age we're lucky we can run at all! I used the starting trick the very first time I started my '56 when I got her home from the PO. It was a cold morning (Nov. 4) and the starter button on the dash did not engage the starter. I'm guessing it was just cold enough, with just enough moisture in the air, and maybe not quite a full charge on the battery. (which is 3 yrs. old) Whatever it was has not re-occured, and I have not had the time yet to anything more than check the connection at the solinoid. Any thoughts anyone? Thanks guys. Happy motoring!
Mike Gambordella '56 Tr3 comm. # 9865
Mike Gambordella

Mike - I'll bet you a Canadian dollar called a "Loonie" because it has a loon on one side, - it has the Queen on the other (worth about $0.60 US) that you hadn't turned on the key !

Don Elliott
1958 TR3A
Don Elliott

Don, Nice try. Yes, I had the key on, the choke out, the clutch in, the whole bit. In fact, I was so shocked and dismayed that I shut it all off and told myself to pretend that didn't just happen! (remember, this is my fist time with the car) Then I started the whole sequence over again with the same result... nothing. Now I had that BIG SINKING feeling. So I raised the bonnet and started looking around with books in hand. That's when I noticed the big rubber boot on the solinoid. So I squished the rubber a bit and boy, it sure felt like a switch. I then walked around and took the car out of gear, turned on the key and just barely touched the "switch" home and wala! she turned over. The rest is history.
(I'll take that "Loonie" now.) Later, Don. Thanks.
Mike Gambordella '56 TR3
Mike Gambordella

This thread was discussed between 25/10/2002 and 17/11/2002

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