[bigzmarine]

I know there is no owners manual for my boat, but I am having a no spark issue with my 2008 sx 19 with a 4.3 I replaced the dist cap, rotor, coil, crank sensor, and harmonic balancer, still no spark, hoping to find a bad fuse, is the fuse box under the dash ? can't see it, everything else works, I have been boating for 30 years and have checked all the usual stuff, kill switch, netural safty switch, key etc, etc, ecu powers up fuel pump etc, help ! thanks

[mikeyt]

Read the STICKY entitled "Troubleshooting Your Starting System" in the General Maintenance section.

[bigzmarine]

thanks, but not a starter problem spark problem

[Tlolesen]

No Spark no Start.

[Ifixmyown]

You might not be able to find a manual for the boat but Merc manuals are readily available from Merc or I got mine thru emanual online. Also look at Merc Easy parts web for all your part numbers. https://public-mercurymarine.sysonli...=englangDB=eng

[pole trick]

It been awhile since I work on a thunderbolt ignition system and dont have manual in front of me.
Normally with key on you should have power to coil. How ever on mercury i/o there is oil pressure switch that cuts off fuel pump or ignition until it gets oil pressure. I don't remember how it all works.. could be oil pressure switch... trace power back from coil until you find problem

[Ifixmyown]

I dont know what version of Thunderbolt you have. If you email Merc with your engine serial number they will email back quickly with the wiring diagram.