1999 Volvo penta 4.3 shutting off after 15 minutes of under load

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Feb 15, 2019
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I have a 1999 Volvo penta 4.3 it shuts off after driving for 10 minutes, stays running if in idle, the only way to start it back up is to jump the fuel pump relay to the battery, I’ve replaced the ignition module, distributor pick up, alternator, fuel pump, fuse panel, rebuilt carb, cleaned up grounds and it still does it, I have 2 boat guys stumped can anyone help?
 

muc

"Retired" Association of Marine Technicians...
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When it won't start, what is missing?
Spark
Fuel
Compression

At least one of the "boat guys" should have asked you that question.

And did you replace all these parts trying to solve this problem?
 

SD2600

Petty Officer 2nd Class
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Jun 11, 2017
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182
Might be related to that fuel pump relay....
have you either tested the relay or swamped it with a known good one?
might want to pull a wiring diagram and double-triple check your grounds

not sure on your boat but when u turn the key to you have an audible beep or can u hear the fuel pump run for ~2 sec?
 

harringtondav

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My Merc 4.3's elec fuel pump has the engine oil pressure switch in it's circuit. No, or low oil pressure = not fuel pressure. The oil pressure switch is located low rear on the port side of the engine. Try jumping the harness and see if the engine runs. But only as a diagnostic. This is a critical safety function. If your engine runs ok, check your oil pressure with a mechanical gage. If OK, replace that switch. The Merc spec is 6-8 psi at idle.
 
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Muc. Thanks for all the replies for help, muc , so I launch my boat and drive it for 15 minutes and it completely shuts down, I have no power at the alternator which controls the fuel pump so I jump the fuel pump relay to get it started. I’ve replaced the alternator, coil, fuel pump, ignition module, distributor pick up, cleaned up all the grounds, rebuilt carburetor.yes I replaced all these parts trying to fix it
 
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Harrington, the wiring on my engine the oil pressure switch is separate from my fuel pump wiring harness, on mine the starter and the alternator control the fuel pump relay, so my question to you is can the oil pressure switch or sensor still shut it off? Thank you
 

alldodge

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only way to start it back up is to jump the fuel pump relay to the battery,

the starter and the alternator control the fuel pump relay

Assuming this is a GL motor your working on

When cranking the motor there should be 12V on the Yellow/Red wire and thru the diode (16) to the relay
Once started power comes from the Green wire from the ALT to another diode to the relay to keep it engaged.

Check for power at and thru the diode when cranking, and also to and thru the run diode once the motor starts

VP GL and GS elect.jpgGL fuel pump wiring.jpg
 
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Alldodge, good info you got me thinking now, I replaced those diodes but now I relize when I’m having this problem I’m losing power when starting and from the alternator, , something is killing power from the starter and alternator to the fuel pump relay
 
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So it wasn’t the resistor and I bypassed the key switch by running a wire from the coil to the battery and boat Still dies after driving for 10 minutes. Then once it cools off it starts up again. So what can electrically heat up and shut off the boat?
 

alldodge

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If your sure its an electrical, then start checking voltages when it dies.
If you still have power to the coil, then I would look into the distributor. The distributor is the EST type and also has a coil inside as well as a pickup module.

Here is the test procedure done on a Merc which will work
fetch


fetch
 

muc

"Retired" Association of Marine Technicians...
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Are you losing spark, fuel or both?
i think the point that AllDodge is trying to make is that parts replacement is a poor substitute for testing.
At this point you have spent a lot of time and money replacing a lot of parts. There is now a very good possibility that you have installed a bad part or made a mistake during the parts swapping.


So, when your engine stops after 10 minutes.
Are you missing
spark
fuel
compression?

​​​​​​​if you can answer that question, one of us will be happy to help you learn how to troubleshoot your problem.
 
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Volvo Penta stalls after 10 minutes of driving

Hi I have 1999 Volvo Penta boat, it stalls after 10 minutes of driving and loses spark, it starts back up after a few minutes and dies again, I’ve replaced every electrical component and wire harness, can anyone help please??!!!!
 

muc

"Retired" Association of Marine Technicians...
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When you lose spark. What voltage is at the purple wire where it plugs into the coil?
 
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