Limping Home Fuel Starved

[LADYBUG TOO]

Today was run the slime off day. I was doing great, running at full throttle for a few minutes, then backing down a bit heading for Ft. Pickens (west end of Pensacola Beach) when the engine slowed, sounded starved for fuel and then quit. I had been heading toward what I thought was a new Ranger 31. Won't know if it was unless they saw me and read this. I dropped anchor and looked for P-codes but there were none. The fuel tank is 2/3 full so I checked the fuel filter for water even though there was no code for it. No water! So then I removed the filter. Couldn't tell much so I filled and reinstalled the filter. I tried the engine and it ran fine at idle but then sounded fuel starved at any appreciable power. Meanwhile I had called my brother-in-law and he arrived in his Shamrock. We ran tandem until the engine quit again so he towed me home. At the dock I was able to back her in and tie off just before a darn thunderstorm hit. It rinsed the boat down for sure. Anyone have any ideas where to start checking before I call my favorite Yanmar Man??

Pat & Carolyn, Ladybug, Too

 

[Levitation]

Lots of possible causes. Have to eliminate them one by one. This is work you can do for free.
First, is the fuel pick up inside the tank clogged - have to unhook the fuel line on the output side of the pump and evaluate the flow into a bucket. Remember, 6 gallons an hour at cruise is a gallon every ten minutes or one tenth of a gallon a minute - not much. SO if the line puts out a stream bigger than a pencil lead, you have plenty of fuel flow.

Then inspect every inch of the fuel line from the pump to the engine for kinks/damage. I have also found line where the inner liner has buckled and blocked the flow, while the hose looks perfect on the outside. This was on a tractor. Drove us nuts.
Next, is there a secondary filter on the engine - there almost always is. Just replace it
Next is air intake - if there is a blockage it will give the same symptoms you have.

Once you have proven that there is adequate flow to the engine, then it is time to spend money on a yammy mechanic.
The possibles become amny - from a frozen turbo shaft, a weak fuel pump (the high pressure side) to the ECM is failing.

Lots a luck :mrgreen:

 

[LADYBUG TOO]

Denny-o,

Thanks for the tips on my fuel problem. Fortunately the fuel filter blocks are 3/8 inch NPT so I bought a 3/8 x hose barb fitting and connected it to the primary and fine filter blocks in succession. I blew back to the tank and could hear bubbling. I installed clear tubing on the hose barb and routed it to a bucket. After turning the key on, the fuel pump began its priming cycle and after a lot of frothy fuel (air) it ran clear. It runs after you turn the key off so I ran about two gallons of fuel through the primary and engine fine filters. The engine cranked immediately and ran smoothly so I thought I was home free. I started the clean up and pulled her away from the dock to turn around and come into the slip head first when she quit. She restarted but gave me a P-Code of P-0191 which is not in the manual but a search online indicates that it is likely a low pressure in the rail. At this point I am convinced it is a restriction in the line between the primary filter and the tank. I plan to reroute and replace both the suction and fuel return hoses as they are crammed tightly against the bulkhead along with some heavy duty wiring. I began the process today(Sunday) and the more I worked on it the tighter I found it. Access to the pick-up is in the cave, a bit tight but I think I can get it out ok.

Again, Thanks!

Pat & Carolyn, Ladybug, Too

 

[Levitation]

Bummer.
Sounds like you have a plan though.
Spent the morning dealing with a defective fuel gauge on the plane. Waiting on parts now.
Spent the afternoon dealing with a broken bearing on a large field disc. Did get the axle nuts finally broke loose - 2 & 3/8" diameter nuts. Had to put a 3 foot pipe extension on the wrench handle and jump on it - vigerously. Will have to suspend the disc shaft with a chain fall to unhook it from the frame. That is tomorrows project.
No problems I know of with the boat ( have avoided looking 🙂
Anyway, if it is a machine, sooner or later you will have to work on it - or pay through the nose. :mrgreen:

 

[Levitation]

Oh yeah. Low rail pressure can also be the high pressure pump. But make sure you have adequate flow with no air bubbles first, as you are doing.

 

[DBBRanger]

This may not have anything to do with your problem, but I am dealing with this at the moment on my R25 so in case it is your problem too......

I see you have a Mase generator. I have developed an air leak in the generator fuel line somewhere. The way it manifests itself is air slowly gets into the supply line when the generator is off. Apparently my leak is at the top of the generator so when the generator pump is not pumping, the fuel wants to go back into the tank since the tank is lower - the air leak allows it. Air bubbles into that line until the air/fuel interface gets to the Racor filter. Then when I run the main engine, the engine will soon stop because it is drawing the air in from the generator side. The key for me was that I could not bleed the main engine because I was always sucking more air from the generator. I finally put an isolation valve on the hose going to the generator as it comes out of the Racor. Now, if that valve is closed, I have no problem with the main engine.

I don't know if your R29 is plumbed like my R25, but in case my symptoms fit your problem, you might look toward the generator.

Good Luck!

Doug

 

[abcandjrc]

Just a thought from someone not too far away, and you surely know the mud-dauber problem in this area. At least your initial post describes what can happen with a clogged vent line. I'm not familiar with the R-29, but it is a quick and easy check when fuel starvation occurs. You can just remove the filler cap.

It doesn't fit the second incident as well, but you had changed the conditions by then and actually got an error code. Strange that with good flow for so long in the test mode the flow would fail when the engine was running. That would make me feel confident in the lines since that flow would be the maximum that could be pulled and most likely to collapse a faulty line. But again, just pumping out several gallons may have pulled a vacuum in the tank. Then air may have been pulled back into the fuel line by the vacuum when you shut off the pump to reattach the lines to the engine. That time air in the line might have been the proximate cause even if the vent is the true problem.

It sure would be worth a check.

 

[WinterIslandYY]

I don't know where you are in this process, but thought I would weigh in anyway. Remove the pick up tube from the tank and you may find a fine mesh screen pushed onto the end. This is alright for gas engines but not for diesels. Diesel fuel has a fungus that will grow, become loose in the tank and eventually will plug up this screen. Remove the screen and throw it away, the primary fuel filter will catch the fungus, which one reason it is there.
To eliminate the genset and main engine from effecting each other, you would have to put in separate intake systems. Gensets don't have very strong lift pumps so a check valve in their inlet line can/will cause running issues.
I would be interested to know if you find a screen on the pick up and its condition.
Cheers,
Peter

 

[LADYBUG TOO]

Peter,

Thanks for weighing in. I started by blowing back through the supply line using just a tube to keep the diesel taste out of my mouth. There was little to no resistance so I did not pull the pick up all the way out. I did replace the entire suction line as it was routed rather circuitously along the port side of the engine compartment and zip tied in with electrical and everything else you could imagine. It took half as much fuel line for the new routing. A friend who was a diesel mechanic in the navy (long before common rail diesels) came over to help and we found leakage all around the secondary engine fine filter. There is a picture on our gallery of the 6BY Sport set up. We found that the filter head had corroded across the gasket seat in three places. Since there is 73 psi after the booster pump it was more than a weep but not as severe as we would have expected. We fixed that problem and darn if it did not dump us again in the ICW on Labor Day weekend with traffic everywhere. Ultimately we discovered that the parts folks sent us a 2 micron filter for our primary. In my eagerness to get going I did not notice the part number. There are pictures of both on our gallery. We had two 2 micron filters in series so you can guess what was happening. The rail pressure is above 23000 psi at 85 per cent load so with the suction restricted the booster pump could not deliver enough fuel to the engine high pressure pump.

By the way, we could not find a reference to the Yanmar part number that would tell us the micron size of either filter. It has been frustrating. We have lost most of our prime season to rains and fuel problems.

Pat & Carolyn, Ladybug, Too

 

[NewMoon]

FWIW,
On our 260hp Volvo 44 diesel, we've been running 2-micron Racors as primary filters for 15 years and 5,553 engine hours so far without a fuel supply hiccup. Seems to me that unless you have old/dirty fuel in the tank the 2-microns should not be part of the problem.

 

[LADYBUG TOO]

Richard,

I don't think the Volvo KAD44P is a common rail diesel like the Yanmar 6BY2-260. The difference is in the fuel injection system on the common rail diesels. The CRD's use rail pressure to inject the fuel so at Idle speed fuel pressure is 6,300 psi and at speed the pressures reach 23,000 psi. The injector is timed and controlled by computer to open and close at specific intervals to allow fuel to flow from the rail into the cylinder. This means that the suction of the engine driven pump must see 73 psi from the booster. We ran fine for a bit but the pressure drop through two 2 micron filters in series is more than the booster pump can handle.

Pat & Carolyn, Ladybug, Too

 

[Boont Boater]

Did you ever get this problem sorted out?