I have a 99 stingray with a mercruiser 4.3 liter I have checked the fuel sytem it is not airlocked and pulls 0 " at idle and will pull 9" of vacuum in less than 10 seconds with the line pinced off I replaced the fuel pump because the old one wouldn't. I also just rebuilt the motor and installed a comp cams 266HR cam (266 intake,270exhaust .5" lift and 112 Lobe angle) and a performer 2114 intake and performer 1409 carb with a 1485 (.089 primaries and secondaries and a 68/57 metering rods) calibration kit. The engine will only run to around 2000 rpm without it backfiring and sputtering and completely falliing on its face. I have changed the jets and meter rods to richen up the mixture (.095 primaries and .092 secondaries with a 65-52 metering rods and the plugs are now starting to show signs of running to rich so I'm certain the mixture is not to lean. I have also replaced the coil, rotor and cap, the ignition sensor module and plugs. I run a compression test and have 145 psi +-5psi in each cylinder. I even installed adustable rocker arms studs so I could better adjust the preload on each lifter because of the bigger cam. I haved checked the advance on the timing in both base mode and normal operation and it hase never gone above 20* at 2000 rpm. So I was checking some older posts where it had been mentioned to jump the oil low pressure cut off switch, the drive switch and nuetral safety switch. When I jump the oil and drive switch no difference, when I jump the nuetral switch the engine dies a few seconds after starting. Why will it not run by jumping the switch is this an indication of a bad ICM. Are there any other tests to check the ICM. also I checked and cleaned the grounds. Thanks for any advice possible.
) so the rest of the system (ignition, fuel, carb) should be good to go...