missed a beat

[Phil B]

Anyone ever had this problem. My atomic 4 will run smoothly for a half hour to 6 hours (longest I have gone when this has happened) but every once in a while it will miss a firing sequence. It does not happen every time I go out either. It is like the engine stumbled and caught itself and just kept humming along after like nothing ever happened.

[marthur]

Our A-4 had something that sounded exactly like you describe. In our case the wire from the coil to the distributor was loose; in rough water one day it finally fell out.

Replacing the wire was all the fix required.

ma

[Don Moyer]

Phil,

It's almost impossible to predict what causes a very sporadic intermittent condition like the one you're reporting with any kind of certainty, but it sounds like a bit of crud might be passing (or trying to pass) through your main jet every now and then, or there might be a questionable connection somewhere in your primary ignition circuit.

To remediate the possibility of fuel being the problem, I suggest that you remove the main passage plug from the bottom of the carburetor, catching and inspecting the fuel that drains out of the carburetor for any sign of particulates, and then pump some more fuel through the carburetor and continue to check it for clarity. When the fuel runs perfectly clear, reinstall the main passage plug, re-prime the carburetor and see if the problem goes away.

If the problem remains after verifying the fuel supply, you can check for a loose connection in your primary ignition circuit by connecting a jumper wire from the large battery cable on the starter solenoid to the positive terminal of the coil. Installing this jumper wire is exactly the same thing as turning on the ignition switch, so you cannot leave the jumper wire connected when the engine is not being operated, or you will burn out the coil. After connecting the jumper, you can start the engine as you normally would, but to shut the engine down, you will have to remove the jumper.

The purpose of the jumper is to bypass all of the circuitry through your cockpit switch and any connections that might be in the primary ignition circuit. If the power interruption never occurs with this wire connected but does occur whenever you remove the wire, you'll have to start checking and/or replacing things within the primary circuit (probably starting with the ignition switch itself.

CAUTION: Remember to remove the jumper wire anytime that the engine is not being operated, just as you have to turn off the ignition switch.

Hopefully these suggestions will at least help get you into the proper system for further diagnostics. Troubleshooting the fuel system if the problem is actually in the ignition system (or vice versa) is like trying to play tennis on a football field.

Best regards,

Don Moyer