running like crap

[b0mbtrack]

Evinrude v-6 175hp, E175EXEOM Optical Ignition System. This engine is just running really bad, checked compressions 105-115 on all cylinders. spark plugs all look good, pulled each plug wire at idle and they are all hitting. While doing full throttle it will run good for about a minute then suddenly the engine will loose a lot of power, the power will then come back and leave again. It also seems like it looses power while running slowly too. Any idea what will cause this or what tests i can do to see if there is a specific cylinder cutting out?

 

[CharlieB]

Re: running like crap

Have you recently changed spark plugs, moved, wiggled any wires?

Check the temp sensor wires, ensure that they are routed outside the head, out, up, and away from the spark plug wires. RF from the plug wires picked up by the temp wire interferes with the ignition.

 

[HighTrim]

Re: running like crap

How long will it usually bog down for at WOT until it picks back up again?

 

[b0mbtrack]

Re: running like crap

It is a quick thing, goes then comes back fast. but then at other times it will stay for some time.
should i give it a shot changing plug wires and plugs? don't think they've been done in some time

 

[clanton]

Re: running like crap

Power pack, ignition coils , and maby timing sensor. I would not replace them without testing them. You check the output to the coils, should all be close to 150 volts with a peak reading meter. Remove the coils and look for arcing from coil to plate that covers pack.