QuestionI have a 78 MGB, That won't start.fIRST I replaced battery,now it turns over,but still won't start.what can I do to check to find what the problem is? fuel pump? start problem, wiring problems, or what??
AnswerHi Donna,
All piston engines only require three things to run,
Compression, Fire and Fuel. However, they have conditions on each.
Compression ---- Enough compression, 125 to 170 PSI on each cylinder.
Fire ------ Good spark (A thick blue spark) at the correct time.
Fuel ------ A combustible fuel available to the combustion chamber in close to the correct fuel/air ratio.
When you have an engine that will not start, never try to look for what is wrong. Always look for the one or more missing of the three.
The most common failure is in the last two so look at them first. This requires a few minor hand tools. Pull a spark plug wire off a plug and either get an extra spark plug or remove one in the engine and attach the plug wire to the loose plug and lay it on a metal part of the engine. Then have someone try to start the engine and watch the plug for a spark. The spark should be a thick (about as thick as a pensile lead) and it should be blue in color (not in the sun light).
If it is then replace the spark plug and wire and take a spray can of starting fluid or something like WD-40 (available at any auto parts store) and spray it into the intake while someone tries to start the engine. If it tries to run for a second or two the problem is fuel.
Either fuel supply to the carb or the carb itself.
Let me know how these tests go and I will guide you to the next step.
Howard
