mercury v6 compression check

[tomslug]

Im wonder why you have to ground spark plug wires when testing compression why cant you crank over with kill switch pulled thanks tom

[XstreamVking]

The kill switch does ground the ignition system. You can pull it for comp check. If not killed, the spark from the coil wire could get you, or jump to a switch box and fry it. You are dealing with very high voltage at the plugs, do not under estimate it's ability to hurt or kill you!

[speedboatjim]

I'm kinda thinking that if you pull your kill switch your power to the starter will be killed also , however if you want to completely eliminate all spark or power to the coil you can unplug the stator and trigger wires at the top of the power head but highly not recommended if your colored blind because you can cause serious damage if you don't get the wires plugged back to the correct colors , trust me I'm a colored blind mercury mechanic
:nonod:

[Go Time]

Kill switch won't affect the starter circuit.....
I don't think they want gas coming out of the spark plug holes and live plug wires jumping around looking for a GND...then ka-bommm. Just leave the ignition off (or pull the kill switch which does the same thing) and use a bump starter switch connected to the starter solenoid....much easier.

[wired247]

Can't crank the engine over with the key with the throttle plates wide open like they need to be. I use the remote starter switch too.

[Jay Smith]

I ALWAYS attach a multi spark tester to ALL plugs when turning a motor over to allow the coils to disapate their voltage while testing...

Jay

[Glasstream15]

I made a spark checker out of some Masonite, nuts, bolts and screws for my I6. 3/8" gap and works great. I won't even think of cranking it without the plug wires grounded thru the checker. I can't afford new switchboxes. It seems to work great. If you need I can get a picture tomorrow.

[wired247]

I made a spark checker out of some Masonite, nuts, bolts and screws for my I6. 3/8" gap and works great. I won't even think of cranking it without the plug wires grounded thru the checker. I can't afford new switchboxes. It seems to work great. If you need I can get a picture tomorrow.

Thats why it works better to keep the key off while its cranking. No spark.

[rev.ronnie]

Key off, jumper switch on solenoid, throttle open. No problem.

[eli]

compression means squat if your looking for condition of the engine ,leak down will tell you ring/cylinder condition .as far as spark testing
I have a unit I can plug all 6 wires at once with 2 forms of ground a clip and eyelet

[Jay Smith]

That's the multi tester I'm talking about they are GREAT tools for testing spark strength too....

Jay