Ignition Problem on top cylinder =-( HELP

quick overview.....1987 merc 70 3cyl 2 stroke, been fighting this problem since end of june.

on cold starts, i often loose spark on the top cylinder, it seems when i move or trailer the boat (TRIM UP) i loose the cylinder,

so first i replaced plugs and wires. boat ran great while kept in the water for a week. took it home, the problem is back. if i jiggled around the plug wire etc it would often come back to life...

next i replaced the coil on that top cylinder, fired up the boat on the muffs, she runs well, all 3 cylinders firing, i think i fixed it, take it to lake 60 miles away, same problem, tried 3 different plug wires, jiggled around etc, no fix, took apart again, traced all wires, everything looks good, try to run it again, same problem, top cylinder is dead cold. back on trailer she goes.....this is where im at now.

NOW i plan on running it in the bucket or on the muffs to test and see if the top coil is getting juice from the switchbox or if the problem is now well before the coil or indeed the new coil itself. what could this possibly be and why. jiggling and tapping no longer brings the cylinder back to life, the top cyl appears dead. PLEASE HELP

I would really like to get this running right and enjoy it a couple more times, but i have my son due in november, so im half tempted to winterized it and forget about it until spring....and move on the more important issues, but i have to at least test and see if the coil is getting power

Re: Ignition Problem on top cylinder =-( HELP

wasnt sure which setting to use on the multi meter so i tried a few. no power getting to the coil for the top cylinder at the coil, no power at the switchbox for the top cylinder either......so??????? the coil is likely okay, its something sooner in the ignition process, could the switchbox be dead, how could i tell

Re: Ignition Problem on top cylinder =-( HELP

after a google search i came across testing processes and charts. one thing that caught my attention was this batch of info i came across, i would fall under number three with my symptoms, which would be switchbox in my case...

OUTBOARD ELECTRICAL & IGNITION TROUBLESHOOTING TIPS

1. Intermittent, weak, or no spark output at two spark plugs usually indicates a bad TRIGGER.

2. Intermittent, weak, or no spark output at all three spark plugs usually indicates a bad STATOR or SWITCH BOX.

3. Intermittent, weak, or no spark at any one spark plug usually indicates a bad SPARK PLUG, COIL, or SWITCH BOX.

Re: Ignition Problem on top cylinder =-( HELP

found a brand new sierra switch box for 117 shipped so i ordered it, after talking to the local merc dealer, he wont tell me for sure its the box but he said the box is a much more high failure part than the stator or trigger. and if it were the stator or trigger it wouldnt have been an intermittent problem for most of the season, they either work or they dont. i guess ill test my luck, the box on it now appears to be the original from 87

Re: Ignition Problem on top cylinder =-( HELP

ttt

Re: Ignition Problem on top cylinder =-( HELP

more interesting info, even though it seems im talking to myself here, i was told by a tech that i could have burnt out the powerpack myself, when the motor was running on 2 cylinders and i was wiggling the third wire etc while it was running to get the 3rd cylinder to fire, he said i may indeed have had a bad coil, but while that cylinder was dead and the boat was running, the charge or spark so to speak could have been traveling back to the powepack and burnt out that cylinder. didnt realize they were so sensitive but it makes sense........well see, pack here by end of week.

Re: Ignition Problem on top cylinder =-( HELP

well despite me talking to myself this whole time, im going to post the solution for my problems so others in the same situation can search it up in the future.
I ordered an aftermarket sierra switch box/power pack and now the boat is back to her former glory, all 3 are firing and it seems to run better than it ever has up high. Im glad shes back to running well again! goodluck all!

Re: Ignition Problem on top cylinder =-( HELP

americaneagler77 said:

well despite me talking to myself this whole time, im going to post the solution for my problems so others in the same situation can search it up in the future.
I ordered an aftermarket sierra switch box/power pack and now the boat is back to her former glory, all 3 are firing and it seems to run better than it ever has up high. Im glad shes back to running well again! goodluck all!

Click to expand...

Glad you got your problem solved and kept the fourm updated.
I didn't see your post till now.

Re: Ignition Problem on top cylinder =-( HELP

Good post.