Low Pressure Fuel Pump noises

R

rpmerrill

Well-known member
Joined
Feb 5, 2016
Messages
608
Fluid Motion Model
C-28
Vessel Name
BAY RANGER
Last weekend I was about 15 miles from home out on the Chesapeake bay.
We had been cruising for over an hour at 14 mph , about 3200 rpm. Suddenly I got a CHECK ENGINE warning on the Yanmar display and the beeper alarm. I throttled back to idle/neutral. The engine sputtered and died. After a brief inspection, I tired restarting. It started but wouldn't run for more than about 15 seconds. On some other attempts it wouldn't start at all. We got towed back home. No other alarms on the CHECK ENGINE screen were highlighted. No real clue as to why it happened. Minutes before the alarm the oil pressure was 72 psi and the temp was 202 degrees. (I was training my son to watch the instruments.) Oh, ya, Yanmar 4BY2 - 2012 with 950 hours.

Back at the boatyard this week, the thrust has been towards some fuel flow fault. There was a suspicion about a slightly loose fuel filter/water separator. Also, as I was able to witness myself this morning, the low pressure fuel pump was making noises. According to the owners manual, turning on the key, the fuel pump is supposed to tun 10 seconds. (This is the method of bleeding the fuel system.... 10 seconds on, 5 seconds off) I cycled the key this way about 5 times and every time it was the same. The pump starts quietly but after a few seconds it gets erratic and buzzy. It sort of sounds like a bumble bee trapped under a newspaper. AND it runs for 30 seconds before it shuts off.

Does anyone else have any similar experience (or different)? Does the pump run until a pressure switch turns it off? As such, is the long run time an indication that the pump isn't coming up to pressure quickly? And finally, my mechanic was able to find a replacement pump for $700+. Thinking that was a crazy number, we are going to look some more. He told me the Yanmar number is 120650-51500.

HELP!
 
Do you know the last time the fuel filters were replaced? It might be a good idea to replace those and also check to make sure all of the fuel line hose clamps are tight.
 
They were all replaced in the fall before winterizing. But we are coming up on 1000 hours service this week so I'm having them all changed just because this engine is new to me.

Just got off the phone with Yanmar (Michael Angland). Very helpful. There are only a couple items we still need to check but then we'll probably be pulling the trigger on a new fuel feed pump. UGH!
 
Actually, the feed pump price is more like $800+ .
Has anyone come up with a lower priced substitution?

We have replaced all the fuel filters and are doing a 1000 hour service this week.
We're also going to be checking the fuel line from the tank to determine if there is any resistance on the suction side.
This pump was replaced only about 200 hours (19 months) ago. (previous owner)
I'd really like to find out the exact cause of the problem before I spend $800.
I realize that I could easily spend $800 in an effort to not spend $800 AND then have to spend $800 anyway.

Still looking for help and advice.
Thanks all.
 
Added thought....

Does the fuel tank pick-up have a strainer?
Is it accessible for replacement or cleaning?

Thanks
 
I have already pm'd you my thoughts, but I will add this in. If you follow the occasional maladies that hit these engines on this site, I am pretty sure the fuel pump issue will be rare. And to have two of them go out in less than 1000 hours strikes me as really rare (I may be wrong). Wondering if there isn't a problem elsewhere that is causing this. This model year has a small wire screen over the tip of the fuel pick up in the bottom of the tank. Others have reported clogging on this screen. It is easy to extract it (access it through the hatch in your cabin step, unscrew the fuel line and pull it out). Given the primary and secondary fuel filters, there is no rational reason for the screen. So I would take that off first and, after replacing the filters, give it another shot and see if it works. Who knows, you may have junk in your fuel tank that is clogging the screen and making it hard for the pump to do its job.

And since this is a marinized BMW engine you can always look at going to BMW or on the internet for a cheaper pump....but we all know how that will turn out. It's a BMW after all. If you sneeze at one it is a pricey repair.

just a guess....
 
Thanks for the positive confirmation of my thoughts about the pick-up. With two pump problems in the last ~200 hours certainly does point to an exterior problem. The fuel pump buzz could very well be cavitation on the suction side of the pump. If we do find a clogged screen we hope the buzz will go away and all will be right with the world. Even if the pump ends up being replaced, we'll have some confidence that the replacement will last a bit longer.

I am curious still about the 10 second pump-up period as noted in the manual... and why mine runs for 30 seconds. Is the runtime determined by a timer, or by a pressure sensor. I'd like to think it is a pressure sensor because it satisfies your an my theory on the screen.

One more fact that occurred to me last night. When talking with the previous owner when I first saw the boat... he was talking about diesels. (This is my first diesel, but had a good friend with a diesel for many years.) I asked about fuel treatments for storage. He told me he never used them. (In fairness, he usually cruised South for the winter, except this past winter.) Hmmm!

As I learn more this week, I'll post the results.
Stay tuned.
 
Since the pump is lubricated by Diesel fuel, "running out" of fuel is a MAJOR deal in the case of a Diesel engine. No big deal with a gasoline engine.

Is there any history of the engine being run out of fuel?

dave
 
No history on that, that I know of.
 
Well, my mechanic pulled out the pick-up (while I was out of town) cleaned it off (some schmutz) and retried the fuel pump re-cycle. All ran well, no buzzing. It appears it may have been the problem. That is, the theory was that the restrictions in the suction strainer caused cavitation on the low pressure pump and a low delivery pressure to the high pressure pump at the 3/4 throttle position on out high speed run.

Today I ran for 10-15 minutes at WOT and all went well. Not a definitive test but a good sign.
Stay tuned.
Thanks all.
 
Great News! Same thing happened to me. I recommend to any R-27 owners with the Yanmar 4BY180 to do the same. It is an easy DIY. Your filters do the job better.

Glad to hear the problem is resolved.
 
Well, I was out of town when my guy pulled out the suction line. I wished I could have seen it myself.
He considered removing the screen per your message but he said it was a one piece assy and removal of the screen would have shortened the pick-up tube and make a whole bunch of fuel unavailable to the pick-up. So, I guess I'll have to do some exploring myself some time later this fall.
 
that's odd. On my boat it was just a mesh screen over the tip of the pick up tube. Just took it off and put the naked tube back in. Yours may be different than mine.
 
Yup, I'm beginning to discover that there are a lot of variations.
 
Spoke to a mechanic out of North Island Boats in Anacortes at the last Seattle boat show about common problems for the Yanmar 4by as it sits in a Ranger. One of the common issues is this fuel strainer pulling from the tank. He said if you don't hear a steady buzz when turning the ignition to on position this is a sign that there could be gunk in this strainer. One more think to add to your start up list of things to check.
 
OK, here it is a month from my last posting on this subject. I only took a couple short runs in Late August and early September. All went well. The weather was miserably hot up here and anything more than an evening out for a glass of wine at anchor was unbearable.

The weather finally broke and this weekend was going to be one of our first and longest cruises, from Easton to St Michaels for two nights. Well, we got about 3-1/2 hours out and within sight of St Michaels, BEEEEEEP. Check engine then quiet. Exactly the same thing except this time we were farther away from home. And my wife was onboard.... not happy. Thank God for TowBoat US. Four+ hours under tow we got home past 9PM.

Monday AM I'm going to have my mechanic check the fuel pick-up screen and I plan on being there to see it. If It is significantly clogged, we'll be cleaning the tank AND most likely springing for the new fuel pump. I can afford the $ for the pump more than I can afford the wrath of my esteemed wife.


any other ideas?
 
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