feul pump not coming on

[crawdadric]

Re: feul pump not coming on

I'm interested in this post however, I'm confused. It seems like a good idea that the fuel pump would not operate with the ignition switch in the run position with the engine not running, because of the possibility of a broken fuel line and fuel spraying everywhere.

Just last weekend, I was working on my boat and I noticed the fuel pump was running with the ignition switch in the run position and the engine not running. I will recheck this later this weekend but can anyone explain how this circuit is supposed to work.
Thank you

Sea Ray SRV300 twin 5.7 mercs with alpha 1 drives.

 

[shelikesit]

Re: feul pump not coming on

I was confused as heck too. I came to the conclusion that since I've always paused after the key turn in my truck for the fuel pump to stop, I do it with this boat. My last boat was mechanical. When I bought this one and saw the electric pump, out of habit, I turn the key, wait a second, and fire it.

These guys know their stuff, so today I convinced myself I never heard the pump on the boat, just habitized the whole situation.

Someone may come back with input for you as the what, when and why. Me??? I just sit back and listen and simply change what I think when some of them speak. (type)

 

[crawdadric]

Re: feul pump not coming on

shelikesit - I'm glad you wrote in about this because I thought it was normal too and would have went on my way not knowing about a potential problem. Your post got me thinking. When I was winterizing and fogging the engine, I thought it was strange that the pump just kept running after the fogging spray killed the engine. That was on my port motor and I don't recall what happened on the starboard.
I'm thinking that the oil pressure switch grounds out the voltage and thats why Don wanted you to remove the two leads and tie them together. Maybe my oil pressure switch is stuck open, removing the ground and the pump will run continuously. I just need someone to confirm the theory of operation. Tomorrow, I will turn both ignitions to the run position without starting the engines and see if they both act the same.
Thank you...
P.S. - good idea on the my boat was stolen web site.

 

[Don S]

Re: feul pump not coming on

See if I can explain it so it makes some sense.
When you turn the key to start, the solenoid on the starter engages. this also puts power to the electric fuel pump (due to how the solenoid is designed) which keeps the fuel bowl full while cranking.
It should also be noted, that the mechanical fuel pumps on older carbed engines also didn't start working until you started cranking the engine.
There is fuel in the bowl when you shut the engine off, so that should be enough to give a couple of squirts of the accelerator pump to start the engine when cold.
Once the engine starts and you let off the start position on the key, the oil pressure has built up and the oil pressure switch makes contact inside the switch and allows power to the fuel pump.
Trace the wires in the drawing earlier in this thread and you will see where the power comes from when in the run position.

 

[Don S]

Re: feul pump not coming on

crawdadric:
The oil pressure switch is a NO (Normally Open) switch. No voltage thru it till the oil pressure builds up Then it closes allowing voltage to the pump. It has NOTHING to do with grounding of anything.
It's a switch and only works on the hot wire.

 

[shelikesit]

Re: feul pump not coming on

After the turn of the year, I have 2 shops that are going to let me sweep some floors and maybe get to clean a wrench or 2. just to watch and learn.

When you turn the key to start, the solenoid on the starter engages.

Since I had power after the solenoid, it must have been good.

Seems these sytems are made with start and stop points, moving step to step, condensed within themselves. And just have to be studied, learned and worked with. Your trouble shooting can't explain that better.

thanks crawdadric, i just started it and waiting on google to pick it up, i think the concept is good, free help in a good area, waiting to see if it takes off

 

[crawdadric]

Re: feul pump not coming on

Thank you Don. I will recheck my engines and see whats going on. This post caught my attention because I thought the pump runs like the way a car does. Maybe on my engine the oil pressure was still pressurized and the fuel pump kept running. When my engine stalled from fogging, I ran over to cut the key off.
Thank you

 

[Don S]

Re: feul pump not coming on

I sure wish something on this *%#@#%^&*# forum would work like it's F-------g supposed to. Now nothing in the "More" links work.
No problem, the advertising works. I may not be long for this forum....... It purly sucks anymore. Slow and doesn't work are the only 2 options.


"Since I had power after the solenoid, it must have been good."

When you followed the troubleshooting methods I gave you, you bypassed that pressure switch by jumpering between the 2 wires. At that point, you have power any time the ign. sw. is in the run position. Has nothing to do with the start position.

I'll have to rework the pictures tomorrow and see if I can't SHOW how the system is supposed to work.

One other note. The pump doens't come on when the switch is turned on only on the CARBED engines. With the EFI engines the pump comes on for 2 sec. and shuts off.

 

[shelikesit]

Re: feul pump not coming on

just keep posting somewhere, please.

iboats may need to look into their servers, i know they'd hate to lose a tech over a simple server problem

according to alexa.com they're the 17,342nd most visited site on the internet, which makes them worth millions. no need for slow servers with such great help around

 

[shelikesit]

Re: feul pump not coming on

ok, its like this, i insist that i can no doubt save money and do it my way like everyone else.

im not only going to change my electronic fuel pump to mechanical, im going to straight out put an automobile mechanical fuel pump on.

i know this is cheaper and better because i know everything right.

big FAT joke so laugh everyone. im just kidding ok.

In all seriousness, I did exactly what I told by you guys and we came to the conclusion my pump was bad, power was making it to it, but not through it.

well........ i was finally able to afford the $222 electronic pump, price upgraded from $213 earlier when diagnosed, and took the time to put it in correctly and tight, and by the time I got to the key switch the boat was running again.

thanks a ton, the boat is going back on the water in about 30 minutes. oh yeah, i added the fuel water separator too. thank for helping me NOT throw a ton of parts at my boat to get it back running again.

the instructions were awesome to find out exactly where the problem was. thank you

 

[180shabah]

Re: feul pump not coming on

Glad to hear you got it going again.

Mine got out bed this year needing a fuel pump so now it will be hanging over my head all winter.

 

[shelikesit]

Re: feul pump not coming on

if only the search function on this forum worked. this thread was a great trouble shooting thread for a bad fuel pump. kind of set me straight in more than one way.