Hard to start when cold

[Captain Obvious]

I've also got an advantage with the flat tops in that I've got the float bowl sight glass on the side of the carbs. I checked the bowl level yesterday before I tried to start the car and it was down a little bit. Evaporation over the past two weeks I assume. Not a whole bunch.. A WAG would be 10% down?

If I shut it off while full hot in the middle of Death Valley one summer afternoon and then came back two weeks later and tried to start it, I could believe that my bowls could be completely dry. But parked (in a garage), even in the middle of summer, in the Philadelphia area that was not the case.

I don't think it's simply the flat tops either. I also ran round tops for a few weeks last summer, and had about the same starting performance. Only time I ever really had to crank the car even remotely as long as 30 seconds was when I just put the carbs on and the bowls were bone dry.

He can easily check this by spraying some gas into the carb mouths, and then crank it over. I'm thinking it will fire right up.

I think a more objective test would be to pull the tube between the bowl and the nozzle before he tries to start it and measures the amount of fuel that comes out. If the volume of fuel that comes out is close to what should be in there, then the problem is somewhere else. Spraying a bunch of fuel into the carb intake before you try to start it can mask a whole bunch of other potential root causes. Checking the bowl level would rule out just the bowl level.

So what I'm going to do is count my lucky stars on just how easily and readily my car starts. Maybe I'm the anomaly?

[Reverend]

Hmm. I have brand new fuel pump and all the other accesories. But still my z takes time to start. And i have no-points dizzy too.. + my starter engine runs twice faster than the original. Only thing that i havent renew is the plug wires. But when warm, it starts faster than lightning, which is nice.

[chaztg]

It's ignition/spark. Check for spark when cranking the engine over.

[dltalfa]

Thanks for all the input guys. However, I'm sure it's not the timing or the spark / fire. If so, it would have starting problems other than just after sitting.

[jaltman]

At first I was thinking the ballast resistor might be keeping the spark too low at startup, but on reviewing the wiring diagram, like many cars, the ballast resistor is out of the circuit during startup. Measure voltage at the + on the coil. It should be 6 volts with the key in the on position and 12 volts with the key in start. If its not, I'd look at the ignition switch.

If the startup voltage at the coil is too low, it'll be hard to start when cold, but ok when the car is warm, since 6 volts is the normal running voltage anyway.

Edit: 2 other thoughts, if startup voltage is weak (<12 volts), jumper 12 volts to it from the battery, but dont leave it there too long after the car starts. See what happens. Thought 2, got a spare coil? An old weak coil might produce the same symptom.

Edited January 12, 2012 by jaltman

[olzed]

dtalfa---when you start the car from cold, turn it off again immediately so the engine is still cold. Then try to start it again. Does it fire straight away.??

If it starts straight away then your slow starting is a fuel issue.. If it is STILL hard to start then some other issue.

[dltalfa]

dtalfa---when you start the car from cold, turn it off again immediately so the engine is still cold. Then try to start it again. Does it fire straight away.??

If it starts straight away then your slow starting is a fuel issue.. If it is STILL hard to start then some other issue.

Yes,..the very second it starts,..you can turn it off and it will start right up.

Naturally,..it needs the choke for a couple of minute but once it starts, it starts the rest of the day within 2 seconds of turning the key.

[Bonzi Lon]

Time the cold start up with a real watch. I think the 'couple of minute' is a slight exaggeration. My 73 with new carbs takes a while to fire after sitting 2 weeks or so, haven't really timed it because I know it is a carbed engine. It just seems to take a lot longer because I'm so used to the fuel injected Saturn, split second ignition.

Bonzi Lon

[olzed]

Yes,..the very second it starts,..you can turn it off and it will start right up.

Naturally,..it needs the choke for a couple of minute but once it starts, it starts the rest of the day within 2 seconds of turning the key.

Problem solved.--- No Problem. ---Lack of fuel in the lines or carbs from sitting.

[dltalfa]

Time the cold start up with a real watch. I think the 'couple of minute' is a slight exaggeration. My 73 with new carbs takes a while to fire after sitting 2 weeks or so, haven't really timed it because I know it is a carbed engine. It just seems to take a lot longer because I'm so used to the fuel injected Saturn, split second ignition.

Bonzi Lon

Please read my original post, I never said "a couple of minutes". I said it takes several seconds, maybe close to a minute.

I have owned, driven and restored antique cars since 1978. I'm very familiar with older "non FI" cars. This one takes much longer than normal. I currently have a 1958 MGA with dual SU carbs. It starts within 5 seconds after a long time sitting.

I just went down to the garage to time my start. It's been sitting for 5days since last start. It took 32 seconds of cranking before it started.

[olzed]

That does seem a little excessive. Wait a few more days, squirt a little gas in each carb and see if it fires .

[Captain Obvious]

I just went down to the garage to time my start. It's been sitting for 5days since last start. It took 32 seconds of cranking before it started.

Yeah, I consider that excessive. Maybe I'm just blessed with a fast starting car, but that's definitely too long where I come from. Your MGA sounds more like my Z.

So have you checked your float bowl levels yet?

I'm assuming your garage hasn't reeked like gasoline for the past five days...