Need help: No spark from coil on 5.7L Mercruiser inboard

[silvster27]

Sorry for the long post, but I'll try to be as thorough as possible:

Hey guys, does anyone know what are the next steps I can take to troubleshoot and find the culprit of my issue. I have a 1992 Sanger FX22 with a 5.7L Mercruiser in it. The last time I took the boat out last season the boat was running (not perfect, but still running strong). A couple weeks back I take it out of storage to get it ready for this summer and it won't start. The engine turns over and over but it just won't start. Lights work and all that, but it just won't even try to start. I confirmed that no spark is coming from the coil, not even a little. I tested this by taking the lead (that goes to the distributor cap) off of the coil and using a screwdriver near the engine block and turned it over and there was no spark. Next I took a voltmeter set to ~V voltage and put the key in the run position and placed the pos+ on the primary side of the coil and the neg- on the secondary side. I would expect that to show 12V, but it showed .2 which is basically nothing (standard interference). I'm not 100% positive I did that test absolutely correctly (should it have been on DC voltage?). Anyways, it appears there is no power to the coil, and I don't know what to test from here.

On my boat there is two wires connected to the primary and two connected to the secondary (plus the main lead that goes to the distributor cap). Also my boat does not have a safety kill switch and I couldn't find a fuse for it. There is one main circuit breaker on the engine, that I am unable to press. I'm not sure if that is the culprit or not.

 

[Bondo]

Re: Need help: No spark from coil on 5.7L Mercruiser inboard

Sorry for the long post, but I'll try to be as thorough as possible:

Hey guys, does anyone know what are the next steps I can take to troubleshoot and find the culprit of my issue. I have a 1992 Sanger FX22 with a 5.7L Mercruiser in it. The last time I took the boat out last season the boat was running (not perfect, but still running strong). A couple weeks back I take it out of storage to get it ready for this summer and it won't start. The engine turns over and over but it just won't start. Lights work and all that, but it just won't even try to start. I confirmed that no spark is coming from the coil, not even a little. I tested this by taking the lead (that goes to the distributor cap) off of the coil and using a screwdriver near the engine block and turned it over and there was no spark. Next I took a voltmeter set to ~V voltage and put the key in the run position and placed the pos+ on the primary side of the coil and the neg- on the secondary side. I would expect that to show 12V, but it showed .2 which is basically nothing (standard interference). I'm not 100% positive I did that test absolutely correctly (should it have been on DC voltage?). Anyways, it appears there is no power to the coil, and I don't know what to test from here.

On my boat there is two wires connected to the primary and two connected to the secondary (plus the main lead that goes to the distributor cap). Also my boat does not have a safety kill switch and I couldn't find a fuse for it. There is one main circuit breaker on the engine, that I am unable to press. I'm not sure if that is the culprit or not.

Ayuh,... Ya don't put the tester leads on each side of the coil,...

Ya put the red lead on the (+) side of the coil, 'n the black lead to Ground, such as the motor's block....

 

[Don S]

Re: Need help: No spark from coil on 5.7L Mercruiser inboard

One other thing, you set the meter on -V to test DC voltage, ~V is for AC voltage. Does your engine have electronic ignition or points ignition.
Assuming it is the Thunderbolt IV ignition, here is the troubleshooting chart.