Triumph Repair: Engine Trouble, triumph spitfire, interval times

Question
QUESTION: Howard- I am restoring a 1974 Triumph Spitfire and hit a bit of a road block this weekend.  The engine has turned over in the past and run for a short period of time before I turned it off.  Since that time period I have done some modifications and now the engine started once this weekend and then died.  I tried for the next 20 minutes to start the engine but it would not fire.  I did give it a lot of gas while trying to start it because it has not really been run for years.  In the end I noticed that the carburetor was leaking gas (not from the fuel line).  I don't know if I have a carb problem or something else.  Since the first time it started several weeks ago, I did mount the anti-run on valve and was wondering if that too could cause the engine to not start.  Your thoughts?
Thanks, Ross

ANSWER: Hi Ross,
To eliminate the anti run on valve as a possible cause disconnect the vacuum hose that runs from it to the carb as a test. The way it stops run on is to apply vacuum to the float chamber of the carb thus preventing any fuel from exiting the main jet into the engine.

All piston engines only need three items to run. Compression, fire and fuel with conditions on each.
Compression -- enough (125 to 170 PSI)
Fire ----- A thick blue spark at the plug close to the correct time.
Fuel ----- A combustible fuel in aprox. the correct fuel/air ratio available in the combustion chamber.

It is said by most mechanics that the easiest car in the world to fix is one that won't run. Because one or more of the three items is missing.

Let me know,
Howard

---------- FOLLOW-UP ----------

QUESTION: Thanks Howard.  After tinkering with different things, I changed the spark plugs and it fired up nicely.  I drove it for a 30 min- 1 hr afterwards in interval times and it then lost power going up a hill and then died.  I could not get it started again.  I have not pulled the plugs but I assume they are fouled up again because it is acting the same as before.  I did add oil because it was running a little low.  I will check the plugs again tomorrow, but wanted to know if I am looking at a bigger problem if I cant keep the plugs from fouling after 1hr of operation.  It has not been run for some time, so it may be working through some bad gas or oil.  Can that cause the problem?  
Thanks again for all of your help.  
Ross

ANSWER: Hi Ross,
While it is possible to foul plugs in an hour you should have seen a lot of either blue or black smoke from the tail pipe when it was running.
Gas can go bad over time but it usually smells bad and is unlikely to run for an hour then not run afterward. Oil does not go bad from age. Remember oil is millions of years old to start with.

When the car stopped you need to test to see why it stopped. Pull a plug and lay it on a metal part of the engine and spin the engine over to see if you have spark. If you do, spray starter fluid or WD-40 in the intake as someone spins the engine to see if you lost fuel supply. This must be done when it stops running.

It is not of any use thinking what it might be. Do the tests and you will know what it is.

Howard

---------- FOLLOW-UP ----------

QUESTION: Thanks Howard.  A couple of questions about the tests. Do you mean pull the plug with the wire still attached or separated?  When you say spin the engine do you mean try to start it with the key or spin the fan?  Also, I did get it running again, but it would not idle and when I gave it gas it did not have enough power to move the car any significant amount of distance in gear.  I did put super unleaded into the tank, is that a problem?  
Thanks, Ross

Answer
Remove a spark plug and then reconnect the plug wire to the plug and lay the plug on a metal part of the engine. Yes use the starter to spin the engine and watch the spark plug to see if it sparks. This is a test for spark when an engine will not start. If the engine starts but will not idle, you don't need to do this test because if it runs, you know it has spark.

How much old gas was in the fuel tank and how much new super unleaded did you add? If there was a lot of old stale gas in the tank and you only added a few gallons of super to it, the problem could still be the gas.

Did you ever do the compression test? You can waste a lot of time trying to hunt and peck at fixing a problem if you skip important preliminary tests that are necessary.

Howard