No spark? 89 larson 3.0 mercruiser 130 hp

[chisjc]

Running out of ideas and hate to just keep replacing things. Here's what I've done.......New points, plugs, wires, cap, rotor, condenser and coil. I've checked the gap twice .22 all good. new battery, charged.

Turns over good, I'm getting no spark. When I put a test light on the positive side of the of the coil or starter selnoid wire that goes to coil, with key on (not cranking) the light is very very dim. Should there be more flowing to the coil? Thanks to all in advance hope someone has some answers

 

[Blk-n-Blu]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

If you look in the Adults only thread at the top of this forum page, Don S has posted how to diagnose these problems. Hope it helps.

 

[chargerboy]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

Take a meter and ground one side to the engine block, and the other side to the coil, measure the voltage. it should be the same voltage as your battery. Another possibility could be weak grounding on your engine. Clean all your ground contacts and try again.

 

[Blk-n-Blu]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

Forgot to mention you can also download a service manual from "Adults Only"

 

[chisjc]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

Thanks. It's not the same voltage as the battery. Much lower so I'm losing to somewhere. The solenoid near the starter or the slave solenoid? That's what I'm trying to find out. I did read the FAQ in sticky refers to not turning over or clicking.

 

[chargerboy]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

Ok double check all your grounding points on the engine block, starting with the battery cables. everything has to be shiny, coat with a bit of dialectric grease or if you don't have it, vaseline, this should help prevent future corrosion. Anywhere you see a wire bolted to the block, take it off and clean it. This should help improve the voltage.

 

[chisjc]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

Just did that. Is there a kill switch or something somewhere?

 

[chargerboy]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

None that I know of on that engine, you might need to trace your wiring back to check for cracks or breaks. I don't recommend trying this, as I'm not sure what would happen, if you want to take a chance, quickly tie a wire to the positive terminal of your battery, and again to the coil positive side and try cranking it over with a good supply of current flowing through. If it starts up, you've simply got wiring issues somewhere from the ignition back to the coil.

Again, I've never tried doing this before, there is a chance it might burn out your new coil. Although it might be the quickest way to narrow down what might be the problem.

Good luck

 

[Bt Doctur]

Re: No spark? 89 larson 3.0 mercruiser 130 hp

Unless you coil has printed on it:Use with External Resistor" you will not see full battery voltage more like 6-9V. If you have installed the points correctly and your sure there opening and closing making contact ,try removing a grey wire attached to the neg side of the coil.(tach feed) it will kill spark, also check for a shorted shift interupter switch, it grounds out the ign systm.