115 HP I6 rough idle and missfires. Need help to interpret readings

[MortenH]

Hello

My 1984 Merc 115 HP I6 is running very rough and missfires badly. All sparkplugs are wet and oily - looks like weak spark. I have checked every connection on the switch boxes - all fine. Then I used a mulitmeter to test trigger and stator. Trigger was within specs, but the stator gave no connectivity between the blue and the red leads, and no connectivity between the blue / white and the red / white leads. Red to ground and red / white to ground was OK. I guess this means the stator is dead - am I correct?
So, now that I am messing with the ignition system, I also would like to test the switch boxes. Is there any way to test them without a DVA? I have tried to search the forum, but I think I need some time to get used to this new edition of this forum...
As a part of the preparation for a new season, I have new fuel lines, new primer bulb, new plugs and fresh fuel.

-M-

 

[ricksrster]

Re: 115 HP I6 rough idle and missfires. Need help to interpret readings

OK. 1984 115hp.Stator: Blue to ground and blue/white to ground should be 5800 - 7000 Ohms. Red to ground and red/white to ground should be 135 -165 Ohms. Trigger: Read from yellow sleeve to black sleeve - Brown to purple, white to brown, purple to white should be 800 - 1400 Ohms. Coils: Primary should be 02 - 1.0 Ohms and secondary should be 800 - 1100 Ohms. Might also want to do a link and sync.

 

[MortenH]

Re: 115 HP I6 rough idle and missfires. Need help to interpret readings

Thanks.
I did a link and sync last year - dont think that this can change over the winter. Also, on my firs two trips, she ran like a beauty.
The specs you gave me on the stator are a little confusing - my Seloc says I shall have 5400 - 6200 ohms between red and blue, and the same between blue / white and red / white. And between red and ground, and between red / white and ground I shall have 125 - 175. Anyway, between red and ground, I have 145 ohms, and the same between red / white and ground. The other measurings on the stator gave no connectivity.

-M-

 

[ricksrster]

Re: 115 HP I6 rough idle and missfires. Need help to interpret readings

The blue and blue /white are the low speed and the red and red/white are high speed. it appears your low speed stator windings are bad. If you could get a hold of a DVA you should be getting 180v from blue to ground and blue white to ground.