My merc 40 hp four stroke shuts down immediatly after start up reves to 3000 rpm them shuts down

Check the TCS (throttle control sensor)

Check your idle control valve.

Remember, they don't hire rocket scientists at Auto Zone, ask your local dealership for the right part and then purchase the part at another auto store.

DO YOU MEAN WHEN YOU ARE ACCELERATING? Or do you mean sitting and reving the engine? If you are just reving the engine in park then the rev limiter is kicking in.

1996 Hyundai Accent ENGINE SPECIFICATIONS 1.5L 92 hp I4 Horsepower 92 @ 5500 RPM Torque (lb-ft) 97 @ 3000 RPM Fuel Type/System Gasoline/MPFI Valves/Valve Configuration 12/SOHC Displacement (cc) 1495 Bore X Stroke (in.) 2.97 X 3.29 Compression Ratio 10.0:1 Turbocharger No Supercharger No

Hi,
Looks like vacuum leaks and some sensors are not connected.
Re check everything again and tell us what happen, so that we could guide you better.
Thanks for using Fixya!

check ur plug wires they might be mismatched ...joe

please check whether you put "W"(Winter mode) instead of "S" .....

hey check the wires to your starter . it sound like its tripping a relay and when it cools off it starts again til it rubs on what ever. did you aleady check the wiring on the ignition coil plug? is it a newer jeep? the connectors on the cam sensor? try that please. still researching.