1998 4.3LX 2bbl mercruiser:
Misfire at idle and higher rpm. Each time I install new plugs she starts quickly and no misfire. 1/2 hour later 20 sec to start and misfires. Pull plugs and they look clean but slight dark crud on thread base after 6 hrs running. Compression all cylinders =190. Timing set @ 9 degrees. Stock plug heat range. Looking for troubleshooting guide for the Thunderbolt V ignition, or other.
Thanks!
Misfire at idle and higher rpm. Each time I install new plugs she starts quickly and no misfire. 1/2 hour later 20 sec to start and misfires. Pull plugs and they look clean but slight dark crud on thread base after 6 hrs running. Compression all cylinders =190. Timing set @ 9 degrees. Stock plug heat range. Looking for troubleshooting guide for the Thunderbolt V ignition, or other.
Thanks!
