Plug not firing - how to tell?

I've got a 1985 Merc. 150 Black Max that recently started running very rough between 1200 and 2000 rpm. Can't have this as my offshore trolling speed is obtained in that range. I know these motors arent the smoothest, but it much worse that before. Fuel system is in tip top shape. New lines, rebuilt pump and carbs, new filters, etc. Seems like a plug(s) is fouling or not firing. Is is safe to remove the plug wire while running in this range in an attempt to find a dead cyliner by drop or no change in rpm. If not, is there another method I should use. She runs great at idle and above 2000. No coughing, sputtering or smoking. Just loads of power.<br /><br />Any other things I should look at? Most wiring under the cowl seems very pliable. Is this normal?<br /><br />Thanks.<br /><br />Brian

Re: Plug not firing - how to tell?

Howdy you can pull the wire while the motor is running be carefull somewhere around 20 to 30 thousand volts it will knock you down and hurt ..you can also check the plug by grounding the plug upagainst the motor and see if the spark jumps the gap whil turning it over it should be a bright strong arc of electricty...good luck HiredGunns from Texas

Re: Plug not firing - how to tell?

Thanks hiredgunns. I'll give it a shot. Rubber gloves would probably good as an extra means of protection or are they not necessary if I'm careful?

Re: Plug not firing - how to tell?

gw204......I have a pair of plug wire pliers that you can get at an auto parts store. They are plastic tipped and the handles are insulated because you don't want to get zapped. I always pre-pull the wires off first if they haven't been off for a while to make it easier...good luck!