Bleeding the Fuel System

[morgantheship]

I have just finished repowerering my H27 with a Yanmar 2GM (replaced a Renault). I have a document that I am putting together that details the entire adventure (with pictures). But my question at this time is the Bleeding of the Fuel System prior to attempting to start the engine. I have attached a few pictures of the new engine in place.

Can someone provide a detailed list of how to do this?

Thanks

 

[kloudie1]

Read the book first .. then this .. then look at teh motor and locate everything.. Then get some rags/paper towels handy..
Morgan, I am going to make an educated guess on this one based on the 3GM .. The idea is to get all the air out of the system between the tank and the injectors on the engine. Your bleed screws are the hex on top of the secondary filter, the little hex in the top of the banjo fitting on the inlet of the high pressure injection pump, and the fittings holding the fuel lines in the injectors on the cylinder head. First, since you are going to crank a while, loosen the raw water pump belt so the pump does not turn when the engine does. Loosen two bolts on the bottom left and move the pump toward the big pulley. Flip the decompression levers so the engine is easy to turn over. Get fuel to the fuel pump. (I don’t know your primary filter situation and whether it is below the level in the tank) Unscrew the hex on top of the secondary filter about two turns. Find the little movable lever that manually operates the fuel lift pump. It is aft and on the underside of the fuel lift pump. Operate the lever, it should have a little free play feel then it should get a little more stiff feeling then it should hit a stop. It should move about 3/8” total. If it doesn’t move enough, rotate the engine a little, try, rotate, try etc until you get a full throw on the lever. (the cam that operates the pump has one lobe on it and it turns at half engine speed, so you may have to rotate the engine as much as one rev to get the fuel pump off the cam so you can fully operate the lever by hand. It is helpful to mark the position on the crank pulley where the lever has the maximum travel. ) Now with fuel at the pump, operate the lever by hand until fuel and no air comes out the top bleed screw on the secondary filter. Tighten that screw while operating the lever and making fuel come out. Next loosen the bleed screw in middle of the banjo connection at the high pressure pump. Again, operate the lever until a good liquid is coming out and no air. Again tighten this screw while operating the lever so that absolutely no air gets into that line. Be careful not to over tighten and strip this one. Next, loosen (about a turn) both of the injector’s inlet screws, the screws that holds the fuel lines going into the injectors, at the side (not top). Open the throttle fully. Get clear of the belts and moving parts and spin the motor with the starter (an assistant or a hand held switch) until you start getting spurts of fuel out at the injectors. BE VERY CAREFUL TO STAY OUT OF THE MOVING PARTS! Tighten the fittings after fuel spurts out each, in order. Fuel should spurt out after about 10-15 seconds. If not, let the starter cool a bit and try again. The engine can start now, so get the raw water pump belt tightened back up, make sure you have water in that pump, flip the compression levers back to normal and she should crank. Run it at a high idle speed to continue the bleed. Now is the tricky and messy part. With the engine running, slightly loosen the bleed screw on top of the filter again and let it bleed until no air is coming out. Tighten it back up. Do the same at the banjo on the HP pump, then the injectors, one at a time. The engine will run roughly on one cylinder when you loosen the fitting on the injector. That is OK .. make sure only fuel is coming out and tighten. Some folks then, one at a time, loosen the outlet fitting on top of the injector and let any air out there as well.. Sounds complicated and it sort of is but the idea is to chase all the air out going toward the injector. Best of luck !

 

[Nereussailor]

So you're telling me that if my motor stalls in a squall and I'm drifting towards a reef, that I have to change my filters and do all of that to get my motor started? Sounds like a salvage to me.

 

[kloudie1]

Only if it stalled because it ran out of fuel or sucked air in for some other reason while running . It is a good idea to not run a diesel out of fuel ...even if you have a self bleeding one.. If you have to change a primary filter, the filter will have to be bled and usually you can bleed the secondary and it will be OK. It will start and you can bleed it while running.. Once you learn the process, it is faster to do it than it is to say it!.. especially if you've marked the pully to give max pump stroke. If you have an electric lift pump, as has been discussed here previously, it goes even faster.
It would be a fine time to put an anchor down .

 

[Nereussailor]

I've got a priming bulb before my Racor filter, Will that make it an easier process? I've never had to bleed my system, so It's all new to me. I emptied my tank before I put it on the hard last. I need to pull the tank and replace the boards under it. I figured that while it was out, I'd give it a good cleaning. I'm going to make the boards under and in front of the tank removeable so that I can have better access to the shaft, transmission, muffler, and anything else that is down there. It was a PITA when I had to pull the tranny and other related parts. The water heater had rotted and leaked so the boards were falling apart. I got everything in front of the tank out but couldn't get the tank out with it full. Time to replace the rest of the rotted stuff.

Dave

 

[kloudie1]

Yup, squeezing the primer bulb will take the place of messing with the manual lever on the lift pump. You’d pressurize with the bulb, open the bleed on the primary filter, let the air out fully, close it, then keeping pressure on, go to the secondary filter bleed, open it until no air comes out, close it, go to the HP pump inlet bleed, open and bleed until no air comes out, and close it.
A “MUST” is to keep pressure on the bulb until after the bleed screws are closed completely, so absolutely no air can get in.
The bleeding over to the injectors from the HP pump has to be done with the engine spinning.
Dave, sounds like you have upgraded a lot of stuff down there in the engine space.
Morgan, I hope this has helped..??

 

[Dan Johnson]

I put my squeeze bulb...

between the Racor and the engine. I didn't want to be pressurizing the Racor if there is back pressure during the bleeding process. The O-ring gasket on the view bowl isn't all that thick and could blow out easy enough with a little too much pressure (yes, I've seen it happen!). Works like a charm until one or two cylinders light up (compression releases being engaged).

 

[morgantheship]

Claude,

This has helped tremendously. I have been reading the Manuel along with your instructions to make sure that I understand everything. I am going to do this on the weekend....I will keep you informed. Thank you so much.

Russell

 

[Nereussailor]

Thanks Claude,
I pretty much replaced everything from the motor back including the shaft log tube. along with half of the teak on the interior, and wiring, and, and, and ................ The PO wasn't very handy with boats, and left a lot neglected. One thing that I wish that I knew, was how many hours there were on the motor. It doesn't have an hour meter. I purchased one, but haven't got it installed yet.It runs and starts without any problems, but it would be nice to know if I'm near a re-power. The boat is in good shape, now, but, like any other boat, it's a never ending job.

Dave

 

[kloudie1]

Unfortunately, Dave, there is no good way to know the engine hours.. but if it has even sounding compression strokes (doesn’t spin faster on one cylinder than the other) and the inside of the valve cover is pretty clean and ya don’t feel a lot of “slop” in the crankshaft when rocking it by hand, ya probably in pretty good shape even though she has some years on. When you go in to check the valve clearances you’ll be able to get an idea of cleanliness and sludge.. Put good diesel crankcase oil in and change it every season or more if it gets really dirty pretty quickly. Good luck with it.

 

[Nereussailor]

Actually Claude, the compression is even and good, the valve cover and head is clean. and there is very little play in crankshaft. The valve clearances were right on a year and a half ago. It's been on the hard since then. I've changed the oil every year since I bought it. I'm guessing, but I think the PO had the marina in Wisconsin change the oil at the end of every season. the insides of the motor show signs of very little sludge anywhere. Thanks for the advice, it's always good to hear someone elses opinions.

 

[morgantheship]

Foiled by the Fuel Feed Pump

Today was the day to start the engine. I followed all of the instructions, even had a friend with to have two sets of eyes and two brains....first prepared the engine with fresh oil for the engine and transmission. Then connected the inlet water to run from a bucket sitting in the cockpit (with a hose handy to continue to fill). Began to bleed the fuel system beginning with opening the fuel tank cock. Opened the air bleeding screw on the fuel filter and began to operate the lever on the fuel feed pump. I pumped the lever up and down, and up and down.....waiting for the fuel to begin to squirt out of the bleeding screw.....but it just didn't happen....no fuel. So after a lengthly time of decision making, we undid the inlet fuel line to make sure that fuel was being delivered to the fuel feed pump... It was, so we reconnected the fuel line. Then after another attempt to bleed the system, we decided to turn the engine over to see if would help. We at first kept the bleeding screw open and hit the start button and cranked the engine....but that is all it did....just cranked. After a few tries we decided to check out the fuel feed pump and it's internal condition.

There is where we found the problem. The outlet valve, outlet valve packing and the metal retaining ring were damaged. The outlet valve was not even correctly seated. The diaphragm looked in good condition but I intend to replace all the internal parts as long as I have it apart. So now I have to wait until Monday morning to order the replacement parts from Torrensen Marine. It will take a few days to ship so it will be later next week before I can attempt this procedure again.

I am disappointed but I leaned more about my engine today.... unfortunately this learning experience has delayed the launch. More to follow...............

 

[Paul F]

Fuel Pump

Know you have a new engine and may like to keep it OEM but, you might consider an electric fuel pump. It makes bleeding very easy. Many new engines have an electric pump installed. I retrofitted my much older 2QM with an electric pump from Auto Zone, a generic Airtex #E8012S, a year ago and wish it had been done sooner. Just by-pass the old mechanical pump and be on your way.

 

[kloudie1]

Man, What a letdown.. Sorry to hear that but you guys sound like ya have the situation in hand. I am not sure that you can get piece/parts for the pump, I think it is only sold as a unit.. Could be wrong.. I hope ya can, Morgan. Some folks on the forum have fitted automotive electric pumps and removed and blanked off the place where the mechanical pump fits..
Best to ya on getting fuel up there..

 

[morgantheship]

Here you can see the inside of the Fuel Feed Pump and the outlet valve that isn't seated properly as well as the cracked retaining plate. I do not know if this was done at the factory and just worked all these years or if the previous owner changed it at one time or another and did not install it properly.

I will find out tomorrow whether I have to purchase an entire new pump or if I can purchase parts. I am tending to think I am going to have to buy the whole pump.