4.3 starts then stalls

Boat is an 86' cadorette holiday 200 engine is 4.3 205hp merc with an alpha one. I just bought this boat and the problem is it starts then stalls after a few seconds. Carb is full of gas and it will restart as many times as I hit the key but then dies after a few seconds. Sounds like a plugged idle circuit in the 4bbl but wanted to see what you guys could add. Thanks this is my first post.

Re: 4.3 starts then stalls

Does the choke work? Do you keep the engine up to 12 to 1500 rpm till it warms up a bit. Carbed engines don't start and run like EFI engines in you car or truck.

Re: 4.3 starts then stalls

Yes the choke works and when I idle it up I get the same result.

Re: 4.3 starts then stalls

Check you have power on the coil + when the key is in the ON position... It sounds like it could be a bad power supply problem.... Verify the electrical side of things before diving into the carby...

Chris.......

Re: 4.3 starts then stalls

does it have the oil pressure switch above the fuel filter? not a sending unit, but a Normally open switch. it 'sees' oil pressure, closes and allows the fuel pump to continue running once the 'start' circut is de-energized. They're a common failure and produce symptoms the same as yours. can be temporarily jumpered to rule it out or to make it back to dock.

Re: 4.3 starts then stalls

What he says...

The oil sending unit is in the same area usually connected by a brass T to the engine along with the pressure SWITCH. The pressure switch is OPEN with no oil pressure thereby killing power to the ignition and fuel pump (purple wire with yellow stripe).

I had a situation where the terminal rotted off the pressure switch. Becaucse the wire was not connected / rotted off, the oil switch must have closed the terminals but the circuit remained open.

The reason why your engine starts briefly is when you crank the starter motor, the starter solenoid (the one actually ON the starter) powers the purple wire will yellow stripe for the duration that you crank the engine. Once you let go of the key, the starter solenoid pulls back and OPENs that circuit. Then the power should come from the CLOSED oil pressure switch.

If you want to easily test this ... block the choke open, disconnect the choke wire (same purple wire with yellow stripe), and power it up. You'll hear the fuel pump run... I bet it'll run.

Re: 4.3 starts then stalls

PS94 said:

does it have the oil pressure switch above the fuel filter? not a sending unit, but a Normally open switch. it 'sees' oil pressure, closes and allows the fuel pump to continue running once the 'start' circut is de-energized. They're a common failure and produce symptoms the same as yours. can be temporarily jumpered to rule it out or to make it back to dock.

Click to expand...

makonnen said:

What he says...

The oil sending unit is in the same area usually connected by a brass T to the engine along with the pressure SWITCH. The pressure switch is OPEN with no oil pressure thereby killing power to the ignition and fuel pump (purple wire with yellow stripe).

I had a situation where the terminal rotted off the pressure switch. Becaucse the wire was not connected / rotted off, the oil switch must have closed the terminals but the circuit remained open.

The reason why your engine starts briefly is when you crank the starter motor, the starter solenoid (the one actually ON the starter) powers the purple wire will yellow stripe for the duration that you crank the engine. Once you let go of the key, the starter solenoid pulls back and OPENs that circuit. Then the power should come from the CLOSED oil pressure switch.

If you want to easily test this ... block the choke open, disconnect the choke wire (same purple wire with yellow stripe), and power it up. You'll hear the fuel pump run... I bet it'll run.

Click to expand...

Hey guys, read what the man wrote...

86' cadorette holiday 200 engine is 4.3 205hp merc

Click to expand...

Mechanical fuel pump back then.... No oil pressure switch...

Also he said:

then dies after a few seconds

Click to expand...

At idle with no load a carb full of fuel will have that engine running well over a minute...

Re: 4.3 starts then stalls

So you think that it is a plugged idle circuit? Cause I'm getting full power to the coil.

Re: 4.3 starts then stalls

1986 (assuming the original engine, as we haven't been given the serial number!) means a Rochester Quadrajet carb. If you've played with carbs before, pull it apart and clean it out. If you haven't done one before, find a carb specialist (not marine mechanic) and have him do it...

Chris.........

Re: 4.3 starts then stalls

Not very familiar with the 4.3 or where their serial number is located but yes it is a quadrajet. Rebuilt many auto/marine carbs as well as many others I'd care to forget so ill order a Sierra carb kit and get to it! Thanks for everyone's input.