QuestionQUESTION: Howard: I own a 1974 Spitfire, but has a 1300 motor in it.That's probably not important to this question. When starting the Spitfire when it's cool it starts up at the snap of a finger. However try starting it when it at operating temperature,epecialy when it has sat for a few minutes it refuses to start. Simply put it just wont start when its(motor)is hot. Any ideas what's the problem with it? Thanks. Jim. Elyria, Ohio
ANSWER: Hi Jim,
If it is a 1300 cc engine you must have two SU carburetors.
If the temp is hot the fuel in the float chambers can start to boil when an engine is turned off. One possible cause is if the charcoal canister is slightly clogged, the expanding vapors in the float chambers will force fuel out the jet and flood the engine. Making it hard to start.
To test for this, get it so you know it is going to be hard to start and hold the throttle wide open when trying to start it. BE SURE to let the throttle off as soon as it starts so you don't over rev the engine. If it starts any easier this way, then check the venting of the float chambers by removing the vent lines for another test of a normal hot start.
Let me know.
Howard
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QUESTION: Howard.You mentioned that my car should have two SU carbs. Mine only has one SU carb. But I'm sure it's a 1300 because the stamped # on engine block starts with FK. The original 1500 engine should have been an FM# on the block. Am I right? Checking numbers, the engine should be a 1972(at least the block is).Does having one carb mean they (previous owner) kept the 1500 head on? Previous owner or owners before me took off the charcoal canister.You mentioned vent lines on float chambers. I don't see any lines from float chambers. Only hoses I see are the rubber hoses about thick as your finger coming out side of carb and a hose going to vavle cover that joins that prviously metioned carb hose. Hope I didn't confuse you? Thanks again Jim. Elyria Ohio
AnswerAs far as the block ID, I think you are correct in that "FK" should be the Mk IV 1300cc (up to 72) and the "FM" should be the 1500cc (73 up)
However, I don't remember any and can't find any record of a single SU carb used on the Spitfire. Everything I remember and can find record of is either two SU carbs or one Stromberg carb. Could be my memory has slipped. ha! All of this is not material but the test for flooding is still good no matter what carb or carbs it has.
If holding the throttle wide open while hot starting makes it start easier then it is flooded. If that does not work spray something like WD-40 into the intake on a hot start. If that makes it start, then it is starved for fuel. With this information you can then find the problem and correct it.
Howard
