ignition problem?

[dburr]

My 79 Merc 50HP has one plug thats much cleaner than the other three. After running for awhile I pulled them to take a look and the bottom one is supper clean compared to the other. Just redid the carbs and fuel lines, boat is much better than before. But does this mean I may only be running on three cylinders. If so how do I fix it? Actually the wire running to that plug is different than the rest. The other three are stock from the thunderbolt energizer. Does this mean someone probably changed it cause there was no spark thinking it was the wire but its actually the enigizer itself. Can only one wire go bad on one of those?

 

[KCLOST]

Re: ignition problem?

Have you checked the spark on that cylinder?

 

[dburr]

Re: ignition problem?

no, not yet. Why would it be so different though?

 

[KCLOST]

Re: ignition problem?

Could be no spark on that cylinder, from the coil, switchbox, trigger, stator... Thus you have no burning fuel and a clean spark plug.. <br /><br />Water intrusion into the cylinder can also be a culprit, (but my guess is that's not your problem)..

 

[dburr]

Re: ignition problem?

Im thinking theres no spark either. Considering that someone has changed the wire in the past, probably tring to fix the problem. IF that the case whats the most likely fault. The enigizer itself? How do I trouble shoot this?

 

[Chris1956]

Re: ignition problem?

dbur, It also could be water intrusion into that cylinder. The water "Steam Cleans" the spark plug. You may be able to test for this as follows. <br /><br />Take out all the spark plugs. Hook the motor to a flusher or put in a barrel. Use a jumper cable to activate the starter solenoid. Spin it until water is pumping out the teltale. Now, take a dry cloth or paper towel and hold it near the spark plug hole on #4 cylinder. If the paper gets wet you got water!<br /><br />Also, the bottom plug wires wear out first. You may be seeing a replacement wire!

 

[dburr]

Re: ignition problem?

Im thinking its not the water problem (though Im an electronics Engineer and not a Marine Mechanic), simply because when I pulled it out it was wet with gas and not water. Does this tell you anything. I'm away on business right now so Im unable to do any more testing until I get home. I guess I should pull the plug and check for spark. I pulled one not to long ago I think it was cyl 2 and it had spark, I never tested the rest. I thought if one had spark they all had spark. Tell me if Im wrong, since the enigizer only has two wires feeding it, that must just be a signal and it then decides which cylinder to fire. Meaning the enigizer must be the culprit if 3 cylinders fire and one doesnt. I just trying to get prepared to change the part thats the problem quickly when I get home considering I go on vacation this saturday and really want this thing runnin tip top. Is there anyway to fix the enigizer, such as cleaning contacts or something?