Engine starting problem

[MikeJenkins]

Hi folks,

I'm looking for some advice. My atomic 4 ran fine last week, but 3 days later it doesn't start at all not even asputter I have checked feul and seen it pumping into jar at carburator. I remoovded and cleaned out new carburator. There were no obvious fuel delivery problems and I have fresh gasoline this season.

I have spark from the coil to ground of about 1/4" to maybe up to 1/2". I also see a spark at each pulg when removed and held to block. I have tried lots of battery power. I do have an Indigo electronic ignition and note that LED on electronics module is not on even though I get a spark.

I checked compression in each cylinder, all were above 90 psi. I plan to check timing and distributor tomorrow any other ideas will be helpful

Thanks and regards

Mike

[rewell6]

Since you have a gas engine just make sure not a lot of gas fumes are nearby when performing the spark test.

How old is the engine? How many hours? How good was the maintenance?

Step 1 - fuel - Are you sure fuel is leaving the carb into the engine. If you move the throttle does a little gas squirt out into the carb? If you can't take the throttle cable loose and open the throttle you will need someone to open the throttle for you while you look in the carb with a flashlight. You should hear and see a little squirt of fuel. If you see a little fuel squirt out skip the next step.

Step 2 - I bet it's fuel related.
I would do this before checking the timing. To test this you could put some fuel in the carb, just about a tablespoon full. Just drop it in the carb, put the spark arrestor back and try to crank. If it tries to crank just a little then your problem is in the carb. Stuck float or needle, maybe a bad accelerator pump (part of the carb).

Step 3 - spark You already checked the spark at the plugs so that's not the problem. Could be a bad rotor (in the dist) or a bad dist cap. A crack (you probably wouldn't be able to see it) in the cap or rotor would cause problems. Could be the electronic module has gone bad. Did the LED come on before?

Step 4 - You can check the timing but unless the timing chain broke that's not going to be the problem. Engines don't usually die like that. Extremes would be a cracked crank or cam, but I bet it's not that either.

[MikeJenkins]

I think the problem is solved. Thanks for your help "Rewell16" or others responding to this post. I did work on the fuel side for a while even to point of putting a littkle gasoline in each clylinder. I checked timing and then replaced coil. The engine fired up with the new coil. I tested spark with new coil and a blue spark for over 1/2" was noted. The former coil produced only a yellowspark less than 1/2". In future I will know that the health of the spark is important.

Regards,

Mike

[NOLAsailing]

The electronic ignition in the A4 is very tough on the coils. Although the electronic ignition is a worthwhile upgrade, try keeping a spare coil along with your other spare engine parts. When I had an A4, I went through a couple coils a year.

[Twoowls]

Your local auto store has some relatively inexpensive high output oil filled coils that should last for years. The Indigo system has nothing to do with coil life.
The coil fires the same number of times regardless of the trigger system. Look for a good name brand racing coil.

[TommyD]

Any PNs for that racing coil? I have a similar problem & have a spare Indigo sourced coil I didn't think of putting on. I always wanted a replacement on hand .. just have to *think* to put t on. Was convinced also it was fuel.

TD