Can spark plug wires cause knock?

[jaredbuybadboat]

Bought an 89 conquest with an OMC 2.3L 4 cyl. Third time out it abruptly started making a knocking sound. I had a marine mechanic check it out and he said when he pulled the wires for the 3d and 4th cylinders (one at a time), the power didn't quit much. He said I might look for a pinched wire. Then I had my roommate's dad (good car mechanic) meet me in the water to listen to the sound and he said he thought it was a rod knocking. We pulled the motor and the oil pan and couldn't find anything wrong, i.e. no metal particles, nothing loose, no considerable scoring on cylinder walls, etc. He said it's possible that the problem isn't visible due to the tight tolerances of the engine.

When we were pulling the motor, I did see that one of the wires had a small gouge in it down to some white material. He said that wouldn't cause the problem but I wanted to get a second opinion. Any advice? At this point I could replace the wires and put the engine back in, but don't want to screw with it if it is not the problem.

 

[ziggy]

Re: Can spark plug wires cause knock?

hum, ya've already got it disassembled. might as well freshin it up. i don't think a spark plug wire will cause yer knock. unless ya thought ya had a knock when it was really a spark arcin out that hole in the wire to groud. got any burn marks anywhers? when ya disconnect a plug wire and nothin happens, it's a sign that that cyl. aint' doin nothing. for what ever reason. i'd think knocks that are mechanical in nature appear when under load.......as for lookin at it after its apart. to be sure brgs. are in tolerance, i'd think ya'd have to plastigage them. that'd tell ya if they were loose....look for abnormal wear pattern...