Mercury I/0 5.7 no start / not getting fuel

Hello all!

I have been a lurker for a while and found some great info to help me along. I am a fairly competent shade tree mechanic and I am pretty up to speed on modern electronics in vehicles. Now to my area of ignorance. I have had my boat for 3 years and never had any problems with it. The out drive started to leak oil and had the upper part of the out drive resealed and did the water impeller myself. My boat is a 1996 Searay with a 5.7 Mercury I/O. The injection system is a throttle body type injection system. Same type as the Chevy V8's from late 80's to the mid 90's.

The boat has old gas in it. About 1.5 years old. And no I wasn't smart enough to put fuel stabilizer in it. I got the boat ready for last summer and it started up fine and ran great. We never got to go out and use the boat since I broke my back and have been recovering from surgery.

I tried to start the engine today, but I wasn't able to get it to start. I was able to get it to start by spaying carb cleaner into the throttle body, so its not a spark problem. So its a fuel problem. I'm sure I need to drain the old fuel out of the boat and start with some fresh fuel. I would expect the engine to at least try to start even with bad fuel. I will change out the water/fuel seperator too while I'm at it.

IMPORTANT PART

I don't think the fuel pump is actually pumping too. When I turn the ignition on, I don't hear the pump and there is no voltage across the power terminal lead of the fuel pump. I don't remember if there was power or not when I tried to turn the engine over.

Does anyone know of anything I may have overlooked? What else I should check and how should I check it. What is the sequence of operation for when the fuel pump is energized?

Re: Mercury I/0 5.7 no start / not getting fuel

when you turn the key it should have power for a few seconds to pressurize the line then shut off. After it starts the pump will have power unless the motor loses oil pressure which shuts down the fuel pump. All this is done from the fuel pump relay. At least thats the way the auto engines work.

Re: Mercury I/0 5.7 no start / not getting fuel

The oil pressure switch is for Mercruiser carbed engines, not EFI. The ECM controls the fuel pump on EFI engines.

Forget about GM's EFI and how it works, this is the marine version, different pumps, wiring etc. Have you checked the fuel pump fuse and relay?

Re: Mercury I/0 5.7 no start / not getting fuel

No I haven't checked the relay. I ran out of juice to do anymore troubleshooting for the day. Time for pain meds and a cocktail. Thats part of the issue for me. I get overwhelmed and worn out from the back pain that I just can't keep going till I solve the problem. I will be trying again tomorrow, depending on how I feel.

On the port side of the engine, there is a black rectangular box with a resettable fuse on it. I am assuming that is where the relay should be. If not, where else should I look? If I open the box, should I find a diagram showing which fuse / switch does what? If not does anyone have a like to a diagram that could help decipher what is what in there?

Also how much of a problem would you think the old gas is ?