Engine dies like clock work, EVERY 40 seconds...

[jkpell]

The engine on my 185 started stalling at a slow idle, this has progressed, today it was dying EVERY 40 +/- seconds. Running at 3000 rpm, dies, idling, dies every 40 seconds or so. I could never run more than a minute. After it died, I would turn it over once for a few seconds, stop, turn it over again and it would crank. Put it in gear, throttle up, plane off, all good, 40 SECONDS later, dead again! Crank twice, gas it, keep going. It made for a very frustrating evening to say the least.
New plugs and fuel filter have been installed in the last month. Has anyone come across this before? I have read it might be a fuel problem, oil sensor, or ignition.

I just wanted to touch base with all of you and see if anyone has had this, before I start trouble shooting each system

2000 4.3L 190 hp 2 barrel carb. If you need more numbers I can get them!


Thanks in advance, I really appreciate any help!

 

[Grub54891]

Sounds like you are running out of fuel.start at the source, check the anti syphon valve at the tank,the screen in the tank if it has one,fuel pump,debris in the filter,did you change the filter at the carb?

 

[jkpell]

I pulled the fuel inlet into the carb, pulled the filter and everything looked good. There was a build up on the spark arrestor and a little on the butterflies, not to bad but it was there.
The boat ran fine for about 30 minutes before it started acting up. I have a feeling that it is an electrical problem just not sure.

 

[Maclin]

I am pretty sure you have an electric fuel pump. For safety reasons those only get power while cranking or only while the engine is running. An oil pressure switch (not sensor) will turn on when oil pressure begins to build, more or less proving the engine is running, power to the fuel pump has to go thru this switch. During cranking there is a bypass circuit that gets power to the fuel pump.

I think what is happening is the electric fuel pump is on during cranking and gets enough fuel into the carb before the key is released to run about 30-40 seconds. If the oil pressure switch is failing then power cannot get to the fuel pump and the carb runs dry like clockwork.

If you can locate the oil pressure switch then you can try jumping across the 2 terminals it has. This will let power get to the pump for testing, to see if the engine can keep running. If this works then you just need to replace the oil pressure switch.

The switch will be plumbed into the same port on the engine block that the oil pressure gauge sensor is plumbed to. The sensor has only one wire, the switch will have 2.

 

[jkpell]

I will see what I can find out. After reading some more into it I really feel it is the oil pressure sensor that has failed.

Thanks for the help so far, hopefully this will solve the problem. Now its time for a LAKE TEST!

 

[jkpell]

The one thing I can see near the oil filter is a sensor/switch with a purple and grey with yellow stripe wire. I am looking for a wiring diagram however does anyone know if this is the oil pressure switch?

Thanks!

 

[jkpell]

BINGO! it appears the oil switch is bad, got a new one to install tomorrow.

Thank you all for the information!