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suspected fuel pump problem, need help

T

the_last_hour

Member
Hi guys need some help once again.
twin 5.7 carbed 2006 crusaders w/ edelbrock 1409 electric choke.....
The port motor will not start, starboard will. Fuel valves have been set so both engines pull off of both tanks without isolating them. After cranking FOREVER, with a push of the throttle and flame arrestor off, I see no fuel squirting into the carb. Comparing the other motor, I see fuel squirting. Also i hear and feel no vibration from port fuel pump when the ignition switch is ON, with the star ignition switch on I hear the pump and feel it. I haven't checked for voltage at the pump yet. I'm asssuming the pump is dead, but I'm confused about the relationship of the oil pressure switch to pump. If the oil pressure switch is dead, will it prevent the fuel pump from running in this situation. Do I need to test both?

Finally, what exactly is the procedure to fill the carb bowls prior to turning the engines over so I don't have to crank FOREVER when I've been away from the boat for a few weeks? The pumps are electric and I know FastJeff has explained to me before how to do this but I forgot. Please explain. Thanks again for all the help.
Steve
 
The dreaded evaporating fuel syndrome....there is no formal procedure. The slickest way is to add a "primer" button to drive your electric pump to fill the bowl. A momentary, N.O. single pole switch should do each engine. The cheap method uses a squirt bottle to add a few ounces to each bowl using a vent tube.

A 2006 model should control the pump via the ECU. Typically, it will turn the pump on a couple seconds when the key is turned on. After the engine starts, the ECU will turn the pump back on once oil pressure is detected. ECU's usually control the pump indirectly, using a relay. If no ECU, then the pump is controlled via a normally open oil pressure switch. Most also supply the pump during cranking, via the starter solenoid.

You may wanna check for a blown fuse before tearing into the piece parts.
 
Mark,
My 2006 model has no ECU, I want to rig the "primer" button as you and jeff have described. Do I only need to apply momentary (+) wire, or ground too, or only ground? I'm not understanding what is being cut out by the oil pressure switch. Is it completing the (+) circuit or the ground circuit when the pressure builds. Remember, I'm no electrical guru, so keep it simple please. Now as for the starter solenoid, it is powering the bypass for the ballast resistor during cranking, should it also be providing a oil pressure sender bypass?
Steve
 
The 'primer' switch normally supplies current to the positive side of the switch. Electrically, it would be connected in parallel to the oil pressure driven fuel pump control switch. (Either switch closing provides current to the pump.)

If you put a primer switch in, you shouldn't need the connection to the starter solenoid.

That plain enough or do you need a drawing?
 
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