Yanmar Fuel System Priming prob

[Jimongee]

Hello folks,
if you can help me-thanks so much. I have a Hunter 356 2002 model. I am in the middle of a grand summer sailing the Great Lakes. Well sort of....! The boat is quite new to me and so after 10 days of trouble free sailing-I decided to change the fuel filters [probably had not been changed in 10 years]. Anyway I did that and then followed the manual to prime [bleed] the system to purge air. I noticed right off that the priming lever does absolutely nothing! Regardless for the next 3 hours I pumped it over 300 times and the engine still will not start. I realize it is not getting fuel. I am a technical guy [former automotive engineer]. The tank has plenty of fuel. There is simply no fuel emitting from the either filter bleed hole during priming attempts. It is Sunday and Yanmar technical help is not available. Do you have any suggestions to purge the air from the fuel system.
thanks so much.
Jim Mongene in Charlevoix, MI

 

[John T1594]

The priming lever only works at the very bottom of the stroke - so push harder!. If that does not work, pulse/crank the engine briefly to re-position the cam that engages the pump and you will get it to work.

 

[kloudie1]

As was said in previous post.... the cam lobe that drives the pump can have the diaphragm already compressed. In order for the little finger lever to work, the cam needs to get rolled a little so the main operating arm of the pump does not have the diaphragm already compressed. Pull the decompression lever and manually rotate the crankshaft pulley clockwise about a half turn .. test the finger lever... if that makes it work , you are good.. if the lever still does nothing, roll the crank another half turn or so and re-try.. You should quickly get to a place where you can feel a full stroke on the finger lever and the pump will rapidly pump enough to displace the air.. Good Luck
Posts #12 and #16 of this thread say this same thing.. http://forums.hunter.sailboatowners.com/showthread.php?t=142949&page=2

 

[Claude L.-Auger]

Are you sure you did not turn the fuel line valve off before you changed the filter ? If so, you can pump until doomsday and you will not get fuel. Assuming it is opened, then you still have air in the system. I never like that little lever on the Yanmar pump as I don't believe it delivers enough pressure to get rid of all the air in the line. And certainly not if air has gotten beyond the fuel filter, i.e. to the injection pump or even to the injectors themselves.

Here is the method I use when necessary on my Yanmar 3GM30. It has never failed for me. This requires a second person but I am assuming you are not traveling alone. If you are, then ask a dock neighbor to lend you a hand for 2 or 3 minutes.

First, unscrew the bleed screw on top of the fuel filter canister (12mm). Second, decompress the engine (3 levers on top. sometimes they are linked together), making sure you have no compression left. Thirdly, shut-off the water intake at the tru-hull valve. Finally, hold lots of rags around the fuel filter canister while you watch the blew screw and have the other person crank the engine with the starter button (or turn the key ?). You should get fuel up there in a hurry and get rid of the air in the line.

Watch and stop cranking when you get clear fuel without air bubbles. System should then be clean up to the filter, which is normally all you need. Tighten back the bleed screw, clean up the fuel you have missed, put decompression levers back in their original position and try starting the engine. It should fire up quickly. When it does, quickly re-open the water intake valve.

If it does not, you may have to do the same thing at the bleed screw on top of the fuel injection pump. Not frequent but it does happen. Same method.

If it still does not start, then you have to bleed all the way to the injectors. This time, because you know you have air-free fuel all the way to the fuel injection pump, you leave the decompression levers in their normal position and leave the water intake valve opened. Have the person crank the engine by pushing on the starter button while you loosen-up the fuel line at the connection on top of the injectors. I may be wrong but I seem to remember it takes a 17mm open-end wrench. Do one at the time until you get clean fuel. The engine will start when you do that. Shut it off and tighten up the nut when fuel is air-free and do the other one. After all 3 are done the engine should run smoothly. Let it run a while to make sure.

Have a nice trip.

If it does not start then you have other problems.

 

[Jim Seamans]

Much easier this way..

http://www.harborfreight.com/fluid-siphon-pump-93290.html

Any outboard siphon hand bulb will work. Place it between the fuel tank and primary fuel filter. As mention above, have a second person squeeze the bulb while you have the secondary bleed screw open to allow the air to escape. Make sure you have paper towels in place to catch any fuel that comes out. Close the bleed screw and hopefully you are done. Every once in a while when trying to start the engine there might be a little air still in there somewhere, so having the other person squeeze the bulb while cranking will clear it out real fast.
Been using this for about 6yrs on my H356 and works...

edit: forgot this works if you have to change injectors also. No need to crack open the line coming into the injector. Squeeze the bulb while cranking... Did this last year and worked like a charm..

 

[Jimongee]

Priming fuel prob

Thanks. One last question. The big water separated filter mounted near the tank has 2 hex nuts and a nylon knob on the top...I don,t know which is the bleed screw. and then are you referring to the other bleed screw located on top of the smaller filter housing? Thanks so very much.
jim

 

[Jim Seamans]

Just saw your post, I leave the primary alone and use the bleed secondary filter... I always change both filters at the same time..

Use a 2 litter plastic bottle cut in off and place round primary filter to catch any fuel. Also use a plastic water battle cut off and place it around the secondary filter to catch any fuel. Keeps any spillage to a few drops...

 

[Jimongee]

Thank you all so very much. I am heading to the boat so you can expect I response later today of my successful accomplishment in getting my little diesel up and running again. We are anxious to cruise the Islands in Cedarville and up near Sault Ste. marie, MI
Jim