The wind bloew the cover off of my 1963 Triumph Herald, so I thought I may as well start it up. It runs fine as long as the choke is out. But when I push the knob in the engine dies. This happened the last time I drove it; only it ran normally until I was about .8 miles away. I got home by pulling on the choke.
When I got home I monkeyed with the carburettor, even though I have no idea what I’m doing. During my monkeying the throttle stuck open. The engine raced when I started it. This happened a few times. After I unstuck the linkage, it ran fine. (i.e., it would not die when I pushed the choke in.)
I know I have a leak in the carburettor, but I drove the car around a lot last summer and the only thing it did was the British car ‘Blap-blap-blap!’ when I was slowing down.
I know that a car needs fuel, air and a spark to run. Engaging the choke increases the ratio of fuel to air, right? So if I lean the mixture by turning the choke off, the engine should speed up briefly before it dies. Only it doesn’t. The revs don’t increase. it just dies.
Carburettor is a french word meaning leave it alone.
OK, if you have to pull the choke out to get the engine to run, this means that the engine is not getting enough fuel. By restricting the amount of air going in at idle the mixture gets rich enough to run. Under this condition, if you push the choke it, the engine will die. Now on the other hand if the engine were running too rich with the choke out, pushing it in would cause the idle to increase.
The most likely cause of your lack of idle is a vacuum leak between the bottom of the carb, and the cylinder head.
Herald engine vibrate. A lot. Ask me how I know this. Look closely at the carb mounting bolts, and the intake manifold nuts. Are they tight? Are any missing? Missing nuts are most likely 5/16 NF thread and can be bought at any hardware store. Are there any vacuum lines that have fallen off the intake manifold? If all the vac lines apear intact, trace them and make sure the other end is attached to something. If you feel like some advanced vacuum leak fault tracing, read on. Warning! I have done what I am about to describe hundreds maybe thousands of times without a problem. There is however, a fair risk of fire. So if you don’t feel comfortable doing this, don’t. Send it to a shop.
OK, you have been warned. Go get a can of carb spray, or WD-40 if you have it handy. I prefer carb spray myself. (doesn’t leave an oily residue) Make sure the contents are flamable. Also get a large cup of coffee. Anyway, start the engine and get it to idle by pulling out the choke. Go under the hood, and start spraying (In samll squirts) carb spray at the base of the carb, and at the intake manifold joint to the cylinder head, and anywhere else you think there might be a leak. If you find a vacuum leak the idle should change big time.
Do not spray at the spark plug wires, at the disrtibutor, or the coil.
Should you somehow set the engine on fire, don’t panic. Stop spraying and throw that cup of coffee at the fire. If there is no fire, drink the coffee.
If you do not find a problem with a vac leak, you probably need to have the carb cleaned and adjusted.
Thanks, Rick. I went out to try your suggestion, and…
It ran fine.
I drove it round the block (about four miles) with no trouble.
When I had it in the shop last year the guy said there was a vacuum leak that couldn’t be fixed. (Blat-blat-blat!) I should get a new carburettor, only the only ones available are Spitfire duals that cost like $700 with a new header. I noticed that on the original carburettor one of the bolts that holds it together is stripped. Two other bolts go through the body and have nuts on them. Maybe I should do the same to the stripped one?
Of course it did. This is one of the laws of British Cars. It will always stop malfunctioning as soon as it gets to the shop. Or in this case post about it on a message board.
A friend says I should go ahead and get the dual carbs and just add it to the price when I sell it. Of course I’d like to paint it before I sell it. I thought of a cheap paint job, but since the seals have to go on it seems a shame to do the work with a cheap paint job. It really is a spiffy car. The longer I keep it, the more likely I am to keep it.
BTW, Rick, there’s a 1963 Triumph Herald 1200 Hard Top for sale in Orange, CA on eBay. It runs, but has a Certificate of Non-operation. Master cylinder needs work, as it takes a few pumps to get the brakes to work. Needs paint, rubber and upholstery. Patchable rust spot on the driver’s floor.
Only one bid so far (310 people have viewed the page) for $800. One day, three hours remaining.
Would that were true! Actually, all it really needs is a coat of paint and a few minor things. Aside from that bizarre carburettor problem it runs very well.
