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CruiseNCatch

Fuel pump not pumping

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I recently replaced the fuel pump and the relay on top of the pump after the starboard engine suddenly stopped after running fine.  The engine ran fine for about five minutes ant stoped again.  I then removed the Carburetor and had it rebuilt.  The engine still will not start. I disconnected the fuel hose from the carburetor and crank the engine a few turns to see if fuel was being pumped — no go. Any ideas what could be causing the fuel pump not to operate.  Note: I installed a new pump and still have the same problem.

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Blocked vent in tank ?  Unscrew the gas cap . Then try a start.

Tank is empty. I did that one for 10 minutes

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Check if a wire is broken at connector.

 

Alsi check if the pump fuse is blown .   Reseat the pump relay.. 

 

 

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With an electric fuel pump it should run (if the fuel pressure is low) as soon as you turn the key to on. You shouldn't have to crank the engine to see if it is pumping with the hose disconnected from the carburetor. So it sounds as though there is no 12 volt feed getting to the fuel pump. You should be able to supply it with a temporary feed to see if it operates.   If it does trace back to find the interruption in the feed.

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10 hours ago, CruiseNCatch said:

I recently replaced the fuel pump and the relay on top of the pump after the starboard engine suddenly stopped after running fine.  The engine ran fine for about five minutes ant stoped again.  I then removed the Carburetor and had it rebuilt.  The engine still will not start. I disconnected the fuel hose from the carburetor and crank the engine a few turns to see if fuel was being pumped — no go. Any ideas what could be causing the fuel pump not to operate.  Note: I installed a new pump and still have the same problem.

Any chance you can post brand, model number and year of the motor? 

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Depending on merc or volvo you have there is a fuse and a relay box mounted above the exhaust manifolds, it has a do not step on it.

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My Starboard engine has a relay immediately above the fuel pump and I replaced it along with the pump.  Where is the fuse? My port engine has a fuse box in the location you mentioned . I did check the fuses in case one was for the starboard engine.  Also when I turn the key I do not hear the pump priming.  Thanks 

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45 minutes ago, CruiseNCatch said:

My Starboard engine has a relay immediately above the fuel pump and I replaced it along with the pump.  Where is the fuse? My port engine has a fuse box in the location you mentioned . I did check the fuses in case one was for the starboard engine.  Also when I turn the key I do not hear the pump priming.  Thanks 

Try wiring the pump direct.

Denny.

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1 hour ago, CruiseNCatch said:

Thanks Denny, I gave up and called a mechanic.

Let us know how you make out, and what the issue was, it may help others.

Denny.

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If you don't hear it priming, it's not getting any power.  Like Denny said, hook it directly to your battery and see what happens.  Most likely it will start, so you need to trace the wires going to the pump.

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4 hours ago, Bt Doctur said:

Not knowing what your working on makes it difficult to give any type of answer

Yep!

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To some degree that is true.  But in his case regardless of the type of motor he has, if he doesn't hear that fuel pump initializing most likely it's not getting any power.  Even a bad pump usually makes some type of noise when you turn the key.

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It turned out there was a short between the ECM and the fuel pump relay.  We disconnected the wire and ran another wire from the coil to the fuel pump relay and everything worked fine.  This was a much cheaper fix than replacing the entire ECM.

 

thanks

 

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On 9/22/2019 at 6:56 AM, CruiseNCatch said:

I recently replaced the fuel pump and the relay on top of the pump after the starboard engine suddenly stopped after running fine.  The engine ran fine for about five minutes ant stoped again.  I then removed the Carburetor and had it rebuilt.  The engine still will not start. I disconnected the fuel hose from the carburetor and crank the engine a few turns to see if fuel was being pumped — no go. Any ideas what could be causing the fuel pump not to operate.  Note: I installed a new pump and still have the same problem.

I haven't seen a motor with an ECM and a carburetor.  Most carbureted motors with electric fuel pumps will only turn the pump on to supply fuel when the engine is cranking or running.  A much safer way to supply power to switch on the fuel pump relay is to use an oil pressure safety switch than wiring it directly to the coil.  Mercruiser engines generally use one, and Volvo motors often use a lead from the starter and one from the alternator to switch on the relay.  Sierra makes one of you need it.

https://www.westmarine.com/buy/sierra--oil-pressure-safety-shut-off-switch--10527075?mrkgcl=481&mrkgadid=3076578718&cm_mmc=PS-_-Google-_-GSC>NonB>Vendors-_-10527075&product_id=10527075&creative=108421554844&device=t&matchtype=&network=g&gclid=CjwKCAjwlovtBRBrEiwAG3XJ-21tR8vBOsy_rw-wifDYzQEu4NXW4-bz5z-hns53aUF8gZwZAxrR_RoCVRcQAvD_BwE

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if carb`d you dont have a ECM,  if your carb`d with an electric fuel pump  it wont energize with the key on.

So what is it you exactly   your working on.? Got an engine serial number

Now if its a volvo ,the alt provides the power for the fuel pump, not the ign switch

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