1994 135HP How to tell if one cylinder is missing?

[janxster]

Hi,
I connected a spark gap tester and all 6 cylinders fire OK it was set at 10mm (minimum for auto electronic ignition) this also equates to 2kV.
Does this mean the ignition system is good?
How can I tell if one or more cylinders is missing?


Also, I replaced the voltage regulators (2X 20amp) and it seems to be ideling better. Is this my imagination?

Thanks,
Da' Janxster

 

[saumon]

Re: 1994 135HP How to tell if one cylinder is missing?

Voltage regulator ONLY regulate the voltage that goes to the battery for recharging, limiting it to 14.4 volts instead of 16-17 volts.

As for spark checking, did you try disconnecting the spark plugs one at the times while engine is running? If the sound doesn't change when you disconnect one, this one isn't firing correctly (important: use the 4$ plastic pliers for this job).

 

[studlymandingo]

Re: 1994 135HP How to tell if one cylinder is missing?

The spark-gap test is good for testing the ignition circuit at idle. I generally set mine for a 7/16" gap (a little more than your 10mm) and look for a strong, consistent spark at each wire. This tells you everything is copasetic on your idle circuit. When you are at running speeds, you are firing off of a different winding on the stator which may not be indicated on the idle test; if you are suspect of this, you may want to run an inductive timing light off of each wire while you are at cruising speeds to see if you have any erratic fire.

Why do you suspect a miss?​