Engine dies

[Kevin215]

Merc. 5.7 carborated year 2000. Engine starts up and idles for about 30 seconds then dies as if starving for fuel. Changed fuel filter. Disconnected fuel line to carb and cranked engine and fuel pump sprayed fuel. If I start engine and give it gas it still dies as if starving for fuel. What do ya'll think?

 

[Don S]

Re: Engine dies

Go to this link

http://forums.iboats.com/showthread.php?t=220416

 

[Maclin]

Re: Engine dies

I bet the oil pressure SWITCH on the engine is bad or the wiring is bad in that circuit. Your electric fuel pump is getting power thru a bypass circuit while cranking and putting just enough fuel into the carb to run about 30 seconds. The fuel pump will only get power with the key in ON position if the oil pressure switch "turns on" by getting enough oil pressure from the running engine.

The oil pressure SWITCH will have two wires more than likely. You can test this by jumpering the wires and seeing if you have power with the key on to the fuel pump then.

You can search thru the threads here and find an engine trouble shooting guide. I am out of town without my normal PC and am missing some things I am used to having with me but someone will probably post here soon with a link to it or the actual procedures.

 

[Maclin]

Re: Engine dies

There you go, Don was about 35 keystrokes ahead of me ....

 

[Kevin215]

Re: Engine dies

Don S. and Maclin, Maybe I'm missing something in the link you posted; it takes me to an outboard discussion so I searched through the Mercruiser forums and cannot find a similar query. However, Maclin, I now want to check my oil pressure switch. Where is it? To me the engine sounds so good for the 30 or so seconds that it is running that I just think that it is either running out of gas (tank is full) or something is shutting it down. Shoot, I just want to run it on the 4th so bad!!!!

 

[Maclin]

Re: Engine dies

If you can find the fuel pump trace the positive wire, it (or one of them) will go to a switch that looks like an oil sending unit, it will be screwed into the block.

Here is a link to another thread here that describes similar symptoms, some of the suggestions, see posts#9-15 specifically, describe how to check for the fuel pump power interruption problem....


http://forums.iboats.com/showthread.php?t=256866

 

[Maclin]

Re: Engine dies

It does help to post the year, engine, drive and engine s/n. All of that will point specifically to the proper manual with the diagnosis charts for your specific setup.

 

[Kevin215]

Re: Engine dies

Great stuff Maclin, I think I can diagnose after that read...will post results and (with my luck lately) another problem tomorrow. Thanks.

 

[Kevin215]

Re: Engine dies

Don S. and Maclin, I'm on the right path for sure now. If I start my engine and keep the key turned with my hand all the way to the right the engine runs perfectly and idles great. I held it there for over 10 minutes and then let it go... about 30 seconds later engine died. So after reading the thread you posted I guess by holding the key to start position I was bypassing the oil pressure switch and the fuel pump was pumping into the carb and engine was running fin. Where is this oil pressure switch? I followed the positive and negative wire from the fuel pump and it goes into a black housing with blue ends...comes out of that housing as a purple with yellow stripe wire and a ground wire...purple with yellow goes to something on carb (black and round)....ground wire goes to a bundle of wires taped together to rear of engine (to ground it I guess). I googled oil pressure switch to see one and I don't see it yet....And when I find it, do I replace it?

Also, when I changed my starter I hooked the yellow and red wire to S and yellow and purple to the other side...Was this right? If I switch them is my problem solved?

And by the way, thanks for leading me on the right track...I know we're almost there.

 

[Kevin215]

Re: Engine dies

Ok, I found oil pressure switch, port side rear by oil filter with one purple wire and one purple with yellow stripe wire going in. I jumpered both these together and engine still died after about 30 seconds. However, if I keep the key turned all the way right as if starting the engine runs for as long as I hold it there...then dies about 30 seconds after letting go.

 

[Maclin]

Re: Engine dies

Is the starter engaged the whole time you are running with the key held to the right? ouch.


Now you need to trace the wire back to the source to see where the breakdown is. There could be a fuse along the way somewhere, it would be best to get the proper manual and look up the fuel pump circuit.

 

[Bondo]

Re: Engine dies

If I start my engine and keep the key turned with my hand all the way to the right the engine runs perfectly and idles great. I held it there for over 10 minutes and then let it go...

Ayuh,.....

You Really should just Sell that boat,+ Find Another Hobby,.....

Btw,......
You can add a Starter to your Shopping List.............

 

[Kevin215]

Re: Engine dies

Bondo, I just bought the 20 outlaw yesterday but still want my Vindicator running. Starter rebuilds are cheap and I just wanted to test that. I want to take it in but nobody wants it until late next week and I can't help but tinker until then. Besides, once we figure it out we're gonna think we should have thought about that first.

Maclin, the manual shows no fuses in line from fuel pump to oil pressure switch or anywhere in the fuel pump circuit. How do I jump the ignition switch to see if that is the problem? I have a yellow/red wire, a red wire, a dark purple wire (this has the alarm on it) and a light purple wire. If I wanted to take the starter out of the circuit which wires to I jump to start the engine?

Kevin

 

[MikDee]

Re: Engine dies

Switch the wires on the starter, one is just for cranking (start) to help it get started, it goes dead once you release pressure on the key, and the other is a resistor wire for (ignition) Run, it is a live wire for as long as you leave the key on!,,, Hope you don't need a new starter