Fuel pump fuse troubleshooting

[sickwilly]

I am trying to get a buddies 1995 Sea Ray with a 4.3 merc running. It's a crappy story, but year ago they were in a horrible car wreck, and both husband and wife spent a lot of time in the ICU. Both are now disabled.

Last year I went and pulled all the plugs and got the boat into their shed so the block would not crack.

This year the boat will not run. I would like to get it running, clean it up, and get it stored again for them. I figure they will need to sell it to help with bills.

Here is the problem:

It is getting no fuel from the fuel pump.

Here is what I know.

The red wire to the starter has juice. When I put the multimeter on the purple wire on the starter and ground it I get no current even with the key in the run position.

previously, I started at the fuel pump -- no current, and the oil pressure switch -- no current, which is why I went to the starter.

From what I have red, there is a fuse on the starter. I have seen some pictures here of a square fuse, but from what I see, it is not logical that it would stop the current from getting to the purple fuel pump wire. Thus, what I cannot tell from reading on line is if this fuse if blown if this would keep the current from going through to the purple wire?

I will head over there again probably this weekend, and want to be armed with what all to test next.

Please help give me the next tests to trouble shoot this.

Thanks,

Richard

 

[Bt Doctur]

with the key "on" there should be 12v to the pressure switch for the pump at the purple wire. in start position the purple w/ yellow stripe coming off the starter solenoid supplies 12v during cranking only

 

[sickwilly]

Thanks for the response.

I had no current at the pressure switch. I checked there first.

Does the wiring that goes the the pressure switch come via starter and starter solenoid?

Am I right to worry about the fuse on the starter and solenoid, or would that fuse not stop the current to the oil pressure switch?

 

[Fun Times]

The 90 amp fuse stops all power going into the engine.

If you have no power only to the purple wire, then you have a problem starting at the ignition key on back.

Lanyard switch at shifter control is on/run position? Do you have power at the helm gauges at key up?

Check and wiggle the 10 pin cannon plug at the engine.

 

[Bt Doctur]

 

[sickwilly]

When I turn the key the boat turns over. Prior to my trying to troubleshoot it, the owner was able to get out there with his son. They hooked up the battery and pored gas down the carb. It will run till that gas is gone.

Wouldn't this rule out the ignition key?

 

[sickwilly]

I need to pull the 90 amp fuse and check it. That will be my next step.

Thanks!

 

[Fun Times]

When I turn the key the boat turns over. Prior to my trying to troubleshoot it, the owner was able to get out there with his son. They hooked up the battery and pored gas down the carb. It will run till that gas is gone.

Wouldn't this rule out the ignition key?

In theory yes it would but your trying to diagnose a problem fresh to you so something new is possible vs what they went through in the past.

I need to pull the 90 amp fuse and check it. That will be my next step.

Thanks!

If the engine is cranking over then this fuse should be okay. For a quick test, Make sure it's there and in place and you have 12v power to the orange wire at the back of the alternator and also the red wire at the back of the 50 amp circuit breaker also check for power at the red/purple wire at the 50 amp circuit breaker while your there. Power at all three locations should tell you the 90 amp fuse is good.

Then a few quick tests of the purple ignition wire with key on confirms all is good there so you can move forward with confidence that you have a problem with the fuel pump circuit which can be a little harder to test by yourself depending on test equipment used, etc.

Good luck.

 

[DeepBlue2010]

I noticed you kept saying "I have no current"

If your multimeter is set to measure current, you will not read any unless the multimeter is connected in series and the circuit is loaded. The multimeter supposed to be set to measure DC volts which is labeled - in most multimeter - with a V and straight line above it or beside it.

The electric fuel pump on this model is controlled by an oil pressure switch on the port side of the engine (the driver side in US driven cars) above the oil filter. There are two switched installed on a T fitting... one of them has a single wire connected to it and the other has two. The 2-wires one is your fuel pump switch.

If you are in doubt about the fuel pump, you can try the following

1. Make sure you have enough oil in the engine
2. Go ahead and short the two wires on the oil pressure switch once the engine start running.

If the engine doesn't die on you as it did before,your oil pressure switch is bad and need replacement.