MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - Fuel Leak

After several months with too much work and not enough time, I finally fired up the TR6 over the weekend. Started well, new alternator brought the voltmeter to 14V in no time, all going nicely. I then reversed out of the garage and noticed a trail of clear liquid on the floor. Further investigation showed that there was a stream of fuel running off the back of the heat shield under the carbs (Joe Alexander type). I had shut down the engine by this point and couldn't see where the fuel was coming from, but the most likely place looked to be the bottom half of the rear carb.

I have carb rebuild kits in my spares box, so could just remove and rebuild, but that will mean removing the carbs and then starting the tuning process again, when I am quite happy with the way the car is running. I figure that after months in a hot garage,the fuel has all evaporated leaving behind some residue on the float, valve etc. so is there a way to get it moving properly again without a strip down? I would hate to rebuild the carbs and go through tuning (and whatever else my shipwright's disease suggests is necessaary!) when all I needed to do was carefully tap the side of the carb and go for a drive!

Cheers
Alistair
A Hewitt

Alister,
Maybe the bottom plug in your carb is not seated properly. Maybe your float is sticking?? Suggest you remove the carb and check the bottom plug. It that's OK, remove the bottom cover and check the float. No adjustment to tuning yet, if it's all in the bottom!
db
Doug Baker

Thanks Doug

Wouldn't I lose the balance if I disconnect the shafts?

Alistair
A Hewitt

This happened to me as well. What happens is that you have a sticking float. Take a screw driver and hit the bottom of the carb (bowl) with the handle. This will free the sticking valve and stop the leak. You can do one better though, by dismantling the carbs and changing the needle valves to a grosse ones from Moss and do away with the problem for good. I hope this helps.
Kypros Christodoulides

Alistair-The easiest culprit to eliminate is the o-ring in the plug on the float chamber. They tend to dry out after a few months inactivity and shrink. The o-ring should be available locally. The size is -114. The plug can be removed without disassembly or removal of the carbs. If that doesn't cure the leak, an easy way to check for a stuck float needle valve is to remove the dome (air valve, and observe the jet while operating the starter (it may take a few seconds for the float bowl to fill).
Berry
BTP Price

I think for Alistair, eliminating the o-ring will not be the easiest culprit, since he has the Joe Alexander
heat shield mounted, and it does not afford easy access to the plug. If your sure it's not leaking from the plug, then try removing the gas line going into the rear carb and shoot a stream of WD40 into the carb to try and unstick the float needle.
Joe S

Alister,
"Wouldn't I lose the balance if I disconnect the shafts?" Don't know, but would think that you can note relative position and reinstall w/o change. Given your situation, it's unlikely that you're going to correct the probolem w/o removing the carb. Of course, you may be able to remove the bottom cover if you have very nimble fingers and a lot of luck in not dropping peculiar screws never to be found again!! Good luck.
db

Doug Baker

Thanks for the thoughts. I had a look last night and found that on the rear carb, there was some sort of tacky residue on the bottom of the body (all around the o-ring). I suspect that either the o-ring has failed or the float valve is clogged, as you all suggested. I don't think I can get the plug out of the bottom without removing the carb, so as you say, Doug, looks like carb off time... I will try to mark the alignment of shaft and clip - it might work, but worst case I am back to tuning again!

As to when I get around to that, I don't know. I just booked flights to go over to England next week, so now I have to wonder what I can get away with bringing back - last time I brought a set of alloy wheels (two boxes, within the baggage size and weight limits - much to the dismay of the United check in desk), so I doubt I can beat that!
A Hewitt

Alister,
You could pick up a bottle or two of Mosstowie Single Malt Scotch for me if you're of a mind to:-) Hard to find here anymore. Distillery was demolished in the purge of 1983 and is now a parking lot or bakery or something. What a waste!!
db
Doug Baker

Doug

What do you think my chances are of finding a bottle of Scotch from a distillery closed for 30 years? Not great, I would say! On the other hand, I am thinking about what parts to buy for a car out of production for even longer, so maybe not so ridiculous!

Cheers
Alistair
A Hewitt

Ah, Alister, but they ran off a few barrells before it closed that are still being bottled; now and again. It's available, just rare and more likely found in London or York than Glasgow or Aberdeen.
db
Doug Baker

Well, unexpectedly positive evening in the garage. I was about to start removing the connections to the carbs when I realised that the heat shield is attached at the air filter side, not the manifold side, so it was off in a couple of minutes. I then leaned over and used the lever on the fuel pump to fill the bowls and very soon it became clear that the front carb was leaking from the bottom plug. Pulled the plug out (I even remembered to hold a cloth underneath to catch the petrol!), replaced the o-ring, put it back and no leak. I was so pleased that I almost didn't notice that the rear carb was now leaking... Same deal - o-ring wasn't sealing, so I replaced it and Robert is your father's brother! At least I hope so. I was all set to dismantle and replace the float valve and all of the gaskets, but not necessary, it seems! I couldn't try a test drive because a) cars were blocking the exit from the garage and b) I may have enjoyed a few adult beverages while pondering the problem!

Out of interest, how long do you guys go between carb rebuilds? Seems like it should be an unusual event, but to have both o-rings fail at the same time seems like maybe other things are going to be deteriorating. I really should use the car more - no doubt sitting around for months at a time doesn't help.

Cheers
Alistair
A Hewitt

DON'T let it sit around for months at a time with etohnal gas mix in it! I use a non-ethonal pump near my house in my TR and XJS to avoid problems.
JT White

This thread was discussed between 23/10/2012 and 26/10/2012

Triumph TR6 index

This thread is from the archive. The Live Triumph TR6 BBS is active now.