I need some advice please, we are about to replace the complete ignition system but I thought I would ask for some advice...
This boat has run great in the past, this is a new problem.
The boat is a friends 1990 21' advantage jet boat. Indmar 330 hp, 454 BBC, Newer EDL 750 Marine carb, emi exhaust, mallory marine dist. magnetic pick up. "A" impeller, rebuilt berkley pump. Started missing a little, kept getting worse all this after we replaced the coil (MSD) because it never started as quick as I thought it should have. Worked great for a couple trips.
Now it starts, runs misses and sometime idles ok, goes to full power then misses, falls flat picks up and gets worse with more time and heat. (hot colorado river area)
We have checked the fuel system, cleaned the carb, drained tanks fresh fuel and filters (fuel water seperator) had a little water in the seperator before the tank was cleaned. The fuel pump is a new marine mechanical unit, fuel tanks are vented ok.
Checked voltage to the ballast resistor it was only 11 volts, 5 volts to the coil - seems low to me, changed the coil and ballast no real effect at all
same voltages....is that too low? also changed the coil to dist. lead.
not much improvement with all that...
So any ideas?
next - wires, plugs, cap rotor, new module?? New DUI marine HEI dist?
we are stumped..
Thanks for the help!!