Ignition troubles

[turbinedoctor]

I noticed while checking my motor with it running that when I pull the plug wire from # 3 and # 6 that there is no noticable difference in the running of the motor. All other cyl. make a big difference. I am using the Merc maint manual for trouble shooting and everything seems to check out just fine. I bought this motor about three years ago and dont notice it running rougher now then when I bought it. I have two switch boxes and #3 is the bottom output on the top switch while #6 is the bottom output on the bottom switch.

I do get a little spark from the plugs but not like the others. I have moved #3 plug and wire up to #2 position with the same results which tells me that the plug and wire are good.



I also moved the trigger signal from #1 to #3 and swapped the plug wire to keep the firing sequence correct. Then #1 along with #3 is not firing.
So it sounds to me like my trigger to 3 & 6 are bad along with something else on #3.

Long story short after looking some more while running it dies altogether, I was able to restart it but now it is missing really bad below 1500 but clears up a little above 1500. Shut it down to check more connections and now no fire at all.

Where to go from here, do all the ohms checks again and write down the readings, replace the stator and trigger.


Any suggestions with in reason will be considered.

Turbo

[spareparts]

sounds like stator, get a dva meter and check all the outputs

[macojoe]

I just had a bad stator but it was effecting high speed, BS checked all with Volt meter and it was indeed bad.

[turbinedoctor]

Rechecked my readings today and one of stator coils is open and the other is real high. Looks like a stator is going to be in order.

Another question, while I'm at it should I replace the trigger since I will be right there? Should I go with CDI parts or Merc. Is one better then the other?

Thanks for the replies,
Turbo

[THEFERMANATOR]

RAPAIR is the reccomended brand by most. IIRC RAPAIR is made by CDI as well.

[macojoe]

ck all related, my rectifier was burned also when we went to replace the stator, we did nothing to the trigger.

[spareparts]

triggers dont normally give the problems that stators do. I'd leave it alone. If you feel like spending some extra money, pick up fresh switch boxes, they seem to follow stators going out. Old switch boxes can cause irregular time events that can lead to engine damage, Theres a capacitor in the bias circut that stabilizes the voltage for consistant timing. the Idle stabilizer on some models varies the voltage in the capacitor to change the actual timing. I've got a good friend that has forgot more than I will ever know about mercurys. He will not rebuild an engine unless it gets new switch boxes(always replace them as a pair). he also recomends replacing them if they are more than 10 years old as a preventative measure.

[turbinedoctor]

Well my new parts should be here today. Last night I checked some of my wires and grounds. I found a bad ground wire to #3 coil and several suspect wires from the switches to the coils. When all is said and done I hope this thing will run like a scalled dog.

[turbinedoctor]

Well Saturday the 13th I had all my parts and the fly wheel puller came in. After a few honeydo's I was able to devote all my attention to the repairs at hand. I started pulling the flywheel at 1pm and by 430pm I was running the motor on the muffs in the yard.

This job went alot easier then I thought it would and the results were worth every penny. Ever since I bouht the boat the motor has sounded the same, a little rough, but I thought it was just the nature of this engine. Come to find out it had been missing on two cylinders the whole time but I did not know it.

Took the boat out Wednesday for an on the water test and was glad to see my rpm's, which I could only get 4600, is now upto 5000. It idles smoother and runs better. So after $295 and about 6 hours I am very pleased with the results.

I tried the seafoam to decarb the engine but did not see the smoking like I have heard others talking about. Maybe I will try it again.

Thanks for yalls support and input.

Turbo

[turbinedoctor]

Pictures to come soon.