Yanmar 4BY2-150 Fuel Pump

[Salty7]

When I turn the key to start my Yanmar 4BY2-150 the red light comes on for about ten seconds and the fuel pump runs for about 45 seconds. The manual says the fuel pump runs for 10 seconds on then the ECU stops it. Can someone please tell me how long their fuel pump runs when you turn the key on, not start, just key on? Mine is possibly the same as all the others and the manual may be wrong or possibly my pump is sucking air or has a restriction on the fuel pickup. With no vacuum gauge in the system I have no way of knowing if the pump is having a difficult time or working normally. I imagine the pump shuts off when a pressure switch reaches a certain pressure. The engine starts and runs fine. Thanks in advance for feedback.

 

[knotflying]

I seem to remember mine ran for about 20 seconds.

 

[Salty7]

Thanks, my memory says mine used to run for less than 45 seconds, but memories can be incorrect, I never really paid much attention to it until a "professional" worked on my engine and changed the filters, now I am working through problems he created for me. I am hoping someone will chime in with a recent actual pump run time from their Yanmar 4BY.

 

[Osprey]

As I recall, when changing out the fuel filters, the pump does not run more than 10 seconds. One repeats the "On, wait, Off" cycle a couple of times to fill the filters and flush out residual air. 45 seconds see me much too long to me.

 

[Salty7]

Thank you Osprey, this is about 10 hours after the filter change and priming. This is every time I turn the key to on, the sequence is now red light on for 10 seconds before it goes out and fuel pump running for 45 seconds before it stops. The engine starts and runs fine but I can't help but wonder if it is constantly self bleeding. What happens when you turn your key to on?

 

[Osprey]

Okay, stopped by the boat this morning to check out the "ignition" ON but without an attempt to start the engine. The red light and alarm sound go off quickly. I timed the pump running time at 30 seconds. For timing I starter a stopwatch at the same time as tuning the key, then rushed back to the cockpit to hear the pump running, then stop.

 

[Salty7]

Osprey, thank you, that is really helpful and fairly close to my run time. Perhaps this is just normal to get up to the required fuel pressure. This means the manual is wrong, the 10 seconds in the manual is just light/preheat time and not fuel pump run time as stated in the manual. It would be nice to hear from at least one more owner to confirm this fuel pump run time so we all have clarity on this item.