86 MerCruiser 3.0 no spark

[Freeman79]

Ok, Mercruiser 3.0 with no spark coming from coil. All new ignition including coil and points/condenser. Points set at .022. With key switch on I've got 12 volts at the + side with points open and 12 volts at the negative. With key switch on and points closed I have 5 at the + and zero at the - . I've disconnected the grey tach wire. WHY WON'T MY COIL FIRE while cranking? The old coil ohmed out where it should have and very close to the same values as the new one. Any insight would be greatly appreciated.

 

[alldodge]

How are checking for spark?

Check at the coil wire, have points open and ignition ON, then use a jumper to ground the Neg side, there should be a spark

 

[Scott Danforth]

file your points. all points need to be filed. if you do not have a points file, grab a fingernail file from your wife/girlfriend

why did you change your coil, it wasnt your coil.

your points gap should be 0.018, which should be 28-32 degrees of dwell (and yes, it is recommended to verify dwell with a dwell meter.

 

[Freeman79]

Thanks for the responses. I was checking for power with a multimeter. I'm checking for spark from the coil output wire with a spark tester grounded on the engine. I changed the coil for reliability once I get it running. All the parts were old. I don't understand how to use the dwell meter on this engine. I've used one before, but there was a window in the distributor cap to adjust the dwell. How is the dwell adjusted with no access to the points? Also, yes there is a spark when the negative side is touched to ground with points open.

 

[alldodge]

How is the dwell adjusted with no access to the points?

Dwell meter is connected and if reading is not within rage, motor is stopped, cap removed, points adjusted and retested

 

[Freeman79]

Oh wow, what a hassle, Thanks for the response

 

[alldodge]

The reason boats don't have a window in the cap is because no one likes a boat to explode. The engine room is an enclosed compartment where gas fumes can build up (reason to run a blower before starting). If there is a open window then fuel fumes can go inside and when points spark, well then bad things can happen