1985 Merc 90 6 cyl no spark #1,2,&6 cyl

[johnewrangler]

I have a 1985 Merc 90 hp straight 6 that I bought used a few weeks ago. I changed the water pump and rebuilt the carbs. It runs very poorly. Starts very hard no power. I replaced the spark plugs and compression tested all cyl at 94 lbs. I checked for spark and found none at #1-2-6. I replaced the ignition coils to the 3 and still nothing. Any ideas on where to look next? Thanks!

 

[Chris1956]

Re: 1985 Merc 90 6 cyl no spark #1,2,&6 cyl

There is a troubleshooting procedure for your ADI ignition on the CDI Electronics web site. Normally a bad switchbox will show no spark on 1,3,5 or 2,4,6. Since yours is 1,2 and 6, it may be something else.

 

[johnewrangler]

Re: 1985 Merc 90 6 cyl no spark #1,2,&6 cyl

Thank you for the reply. What sire would I go to?