Mercruiser No Start

[luckydog49]

I just brought home(new to me) Bayliner 2007 Discovery with a 5.7 carb motor. The boat is on a trailer, I hooked up the water muffs to start the boat, The boat turns over, no start. Made sure safety swith was on, no start. Pulled aircleaner, no fuel spray from carb when pumped. Poured some fuel into the vent, put the aircleaner on and boat started for a few seconds. I now assume I am not getting fuel to carb, cracked the fuel line to carb, no fuel. hooked up a suction pump to fuel line to the fuel tank, plenty of fuel. Fuel pump looks electric with wires running to it. Any Ideas how to check fuel pump wiring, or is their a relay that may have failed. Boat has less than 50 hours on it, and ran in the shop before I bought it. I did move it on the trailer for 300 miles. Thanks Ro

 

[Bondo]

Re: Mercruiser No Start

Any Ideas how to check fuel pump wiring, or is their a relay that may have failed.

Ayuh,... We don't care if this is a Bilgeliner or a Chris-Craft,...

What's the motor,..?? Merc,..?? Volvo,..??

 

[Fun Times]

Re: Mercruiser No Start

Quote]Mercruiser No Start,I just brought home(new to me) Bayliner 2007 Discovery with a 5.7 carb motor.
If it's a 2007 Bayliner then it better be a mercruiser or someone might be out of a job. J/K Sorry Bond-o I had to say it. You will get me back someday I'm sure. He did let us know what engine he has for the most part anyways.

 

[Bondo]

Re: Mercruiser No Start

Ayuh,.... My bad,... Missed the title....

OK,...
When the key is turned to Start,... There should be power from the starter to the fuel pump....
After the motor starts,... There's power fed from the ignition circuit through the oil pressure switch, to the fuel pump....

 

[Don S]

Re: Mercruiser No Start

Your electric fuel pump gets power from the starter solenoid when the engine is cranking, and an oil pressure switch when running.
I would start at the electrical connector at the fuel pump. Disconnect the wires from the pump, then with jumper wires directly to 12V and ground you can check to see if the pump runs. If it does, you will have to check the wiring back to the starter. There are no relays, fuses, or circuit breakers.
Up in the Adults Only sticky, you can download the OEM service manual for your engine with a wiring diagram. You want manual #24

 

[ChrisCraftJohnny]

Re: Mercruiser No Start

Don,

So when you turn the key...

1. The fuel pump gets energized via the starter solinoid.
2. The engine turns over and starts (hopefully)
3. Ignition key is released & power stops flowing to the fuel pump & starter.
4. As the engine is running oil pressure builds and 12 volts gets sent to the fuel pump via the oil pressure sender and continues to run the fuel pump.

So is there a small bit of time that the fuel pump stops working for 1-2 seconds while oil pressure builds?

Thanks.

 

[Bondo]

Re: Mercruiser No Start

Nope,...
The fuel pump gets power from the starter, Only while cranking...
The oil pressure comes Up at the same time...
Then,...
Power from the ignition circuit goes through the oil pressure Switch to the fuel pump...
As soon as the key is released...

 

[Don S]

Re: Mercruiser No Start

So is there a small bit of time that the fuel pump stops working for 1-2 seconds while oil pressure builds?

It usually doesn't take that long for the oil pressure to build enough to close the switch. It's only a 5-7 psi switch. Besides, if the carb is full of gas while cranking, the engine will run for 15 to 20 seconds on whats in the bowl of the carb.

 

[luckydog49]

Re: Mercruiser No Start

Thank You all for the input!! I'll give it a try this weekend, knowing there are no fuses, or relays, and how to power up the pump to check it makes this a lot simpler to figure out. Thanks again Ro