Accelerated Fuel Pump Clicking
6/10/2020 To see more info regarding bleeding, please review the Engine section in this tech wiki. Thx, Stu
I recently changed both the filter and the pump, and had a similar experience. My uneducated guess is you may have a bit of air in the line. There is a bleeder valve on the engine ... once I got the air out it worked fine. If it persists, look at all the connections leading to the pump, including the filter housing for air leaks... Good luck! (K2/ Stormalong)
We were told by the diesel seminar people that this chatter was normal as it initially pumped. It's been initially doing it since day one 9 years ago. No idea why it does it. (AdriennAnn C34 NAIAD (#1020) LI NY)
wow i got the same thing yesterday, and just asked the yard about it. they said it was ok, just pumping fuel in. but last year it was the slow steady clicking, not fast. yard said to give it a little throttle before starting which i will try( they just put brake on the throttle cable, maybe that changed things?) (Ekko1@aol.com)
The high speed chatter on my fuel pump can not be considered normal operation as some of you have recommended. In as much as my boat is 9 years old and i just completed a 1600 mile cruise down the ICW this chatter noise was never present before. The ticking would increase slightly during starting, but now i have a loud on-going chatter sound. B. Mueller Karista 1012
Mine did same thing until fuel system vented well. Open bypass valve to vent to tank. Then reclose. Jeff Salty Dog C34 #1102
Each "click" is one cycle of the fuel pump. The pump stops running when sufficient pressure has been built up in the downstream fuel line. It is "normal" when first starting to have rapid clicks to build up any pressure that has been lost from the system as the engine was shut down. During operation, as fuel is injected into the engine, there will be a steady slow click for fuel makeup -- the "speed" of the clicks depends on the current fuel consumption of the engine. However, if the fuel pump continues to click rapidly then I would suspect one of three conditions:
- You have a leak in the fuel system -- some leaks can be internal so may not be seen outside the engine.
- Air trapped somewhere in the system.
- Your pump diaphram has a tear.
Since you just changed your Racor filter, I would suspect that it isn't installed correctly or you let too much air into the system that hasn't been evacuated. If the fuel pump can suck in air at the filter, it might continue to run because it is slightly air bound, but not air-bound enough to shut down the engine. I'd take the new filter off and reinstall it, and then go through the system bleed procedure. Pete
I addition to the already mentioned possible causes of the fuel pump chatter, please consider that the fuel bypass valve may be partially open allowing fuel to pump back to the tank. This would reduce pressure and cause the pump to run faster than usual. Paul Law, Avalon #912
As you can see from the replies that you've seen to date, there can be a number of causes for the fuel pump pulsing very rapidly. Normal pulsing should be about one pulse every two seconds without the engine running. As one of your replies mentioned, an open bleed valve could be the cause. As I've written in a number of Mainsheet articles, you could also have a clogged fuel screen pick up tube in the fuel tank and the pump is trying to suck fuel through a clogged strainer. If this anomaly just started after you changed the Racor filter, it sounds as though the Racor filter may not be seated properly and you are getting an air leak; or you did not completely get all of the air out of the new Racor filter. I'd recommend you reseat your Racor filter to ensure that the flat gasket at the top and the O ring at the bottom are completely seated. Then I would repurge the system using the bleed valve until you can completely close the bleed valve without the engine running and hear the rhythmic tick every two seconds. Ron Hill, Apache #788