'89 Mercruiser 5.7L Ski, no coil spark?

[Chris Whittley]

Just did an ignition tune up, cap rotor points condenser and coil but no spark. To me it seems to be the coil as I'm getting >8 volts at the coil terminals when turning over which I'm told is OK. I've taken the high voltage coil lead to ground to verify spark coming out but nothing. I've also done this with a jumper wire from the battery positive to the positive side of the coil, still with no success. The only conclusion I can draw is it's the wrong coil?? I've tried a second new coil as sometimes you can get a dud. It has an external resistor which I haven't bothered with because I'm getting voltage to the coil.
Any help would be great, I can't afford to loose any more hair, thanks.
PS There are different coils listed for this engine so there could be some confusion but I'm trusting the marina has chosen the right one Napa #903.

[redtech]

check the pionts and did you clean them before installation often coated to prevent corrosion in the package also check wires under cap for grounding

[Chris Whittley]

Thanks Redtech, I've double checked the points but not cleaned them. I didn't spend too much time under the cap because I'm not getting any juice that far. If the coil was generating spark I'd look further down stream.

[redtech]

the coil gets it signal to spark from the points
if the pionts are not opening and closing no spark at all
only thing down stream from the coil output wire is the rotor, cap, wires, and plugs. the points are upstream to the neg post on the coil

[redtech]

chris, sorry about being short in last message just bin a long day and i've spent a lot of time trying to get younger mechanics to understand pionts. sometimes what one person sees as eazy others don't. just don't ask about cars and i'll be fine, i'm a boat technician not a car mechanic

[Chris Whittley]

Thanks very much, I was told from various sources that I could simply pull the coil lead off and test for spark if I placed the lead near a ground, like the block. Therefore I've been suspecting the coil due to no result, sounds like I'm looking in the wrong place.

[Chris Whittley]

I'll make sure the points are clean,try again and report.

[Chris Whittley]

Hi Redtech, I'm working on the points, cleaned them and checking ground. I have continuity between the contact points when closed and open which can't be right, no make and brake??

[redtech]

sounds like your on the right path
look for a wire grounding uot the pionts most likely going to the condenser or the neg post of the coil

[Chris Whittley]

Found it, the copper tab on the points unit was grounding out on the distributor housing. Can't tell you how much I appreciate you putting me on the right path.