I recently purchased a 1986 Hunter 34 with the Yanmar 3GM30F engine and need to bleed the fuel system. I can bleed the air from the fuel filter and the fuel return line but I cannot bleed the air from the fuel injection pipe because I can’t loosen the nipple on the fuel injection valve side. This nipple has been rounded off by the previous owner making the 17mm wrench ineffective. I have tried using vice grips but still cannot break the bolt. In the area, there is very little working space and I am also limited to using an open-end type tool since the fuel injection pipe line is a part of the nipple that I am working with. Any suggestions will be appreciated. On another note, once I get the nipple loosened, it will need to be replaced. Is this nipple a separate fitting or is the nipple and the fuel injection line considered a single replacement part?
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Are you usins a 6pt. or 12 pt.
wrench or socket? six pt would be better. Also make sure you are using a good quality tool. I perfer Snap-On. If you can get a wrench on it, as opposed to a socket I would try a 17mm line wrench. If the fastner is badly stripped, you can try the next size down 12 pt socket and tap it on with a hammer. Either a 16mm or a 11/16 fractional. Above all, try not to break the fastner off, or you will have a real can of worms. The metal line that goes from my fuel filter, to my distribution pump on my 3Hmf30 (i think, I don't have the manueal handy is a 10 mm with the addition of a phillips screw head. it is easy to ope, Be careful not to over tieghten and crush the plastic washer. Hope this helps. Chris s/v Tidesong
wrench or socket? six pt would be better. Also make sure you are using a good quality tool. I perfer Snap-On. If you can get a wrench on it, as opposed to a socket I would try a 17mm line wrench. If the fastner is badly stripped, you can try the next size down 12 pt socket and tap it on with a hammer. Either a 16mm or a 11/16 fractional. Above all, try not to break the fastner off, or you will have a real can of worms. The metal line that goes from my fuel filter, to my distribution pump on my 3Hmf30 (i think, I don't have the manueal handy is a 10 mm with the addition of a phillips screw head. it is easy to ope, Be careful not to over tieghten and crush the plastic washer. Hope this helps. Chris s/v Tidesong
3gm30 bleading air
John-I am a little confused on where you are trying to blead the fuel system. You should be able to start you engine with out bleading the injectors.If you have blead the filters (you most likely have two) then blead the fuel injector punp (it is a 10mm screw type bleader)With the injector pump blead it should start the engine with out bleading the injectors. I am confused about what you are bleading because you can get a socket or box wrench on the fuel pump bleader.I may be off base here but that is how it works on my 3gm30f amd I would imagne your is the same unless they have a different fuel pump on that year model. good Luck!
John-I am a little confused on where you are trying to blead the fuel system. You should be able to start you engine with out bleading the injectors.If you have blead the filters (you most likely have two) then blead the fuel injector punp (it is a 10mm screw type bleader)With the injector pump blead it should start the engine with out bleading the injectors. I am confused about what you are bleading because you can get a socket or box wrench on the fuel pump bleader.I may be off base here but that is how it works on my 3gm30f amd I would imagne your is the same unless they have a different fuel pump on that year model. good Luck!
I'll try to make my question less confusing
I can see how my post could hard to understand. It was even more difficult to write. This is the first time I have attempted to bleed the system so all of this is new to me. I will try to rewrite my post using the manual as reference. Step one. “Bleed the air from the fuel filter.” I did this using a 10mm box end wrench Step two. “Bleed the air from the return fuel pipe” I did this on all three cylinders Step three “Bleed the air from the fuel injection pipe” This is where I am having my problem. The instructions say to “loosen the nipple on the fuel injection side, set the lever to the decompression position and crank the engine” I cannot loosen the nipple on the first cylinder (the one closest to the front of the engine) and cannot use a box end wrench since the fuel injection pipe is fitted to the nipple. This procedure is described on page 13-8 of the Yanmar Service Manual for models 1GM 10, 2GM20, 3GM30, and 3HM35 engines. Thanks
I can see how my post could hard to understand. It was even more difficult to write. This is the first time I have attempted to bleed the system so all of this is new to me. I will try to rewrite my post using the manual as reference. Step one. “Bleed the air from the fuel filter.” I did this using a 10mm box end wrench Step two. “Bleed the air from the return fuel pipe” I did this on all three cylinders Step three “Bleed the air from the fuel injection pipe” This is where I am having my problem. The instructions say to “loosen the nipple on the fuel injection side, set the lever to the decompression position and crank the engine” I cannot loosen the nipple on the first cylinder (the one closest to the front of the engine) and cannot use a box end wrench since the fuel injection pipe is fitted to the nipple. This procedure is described on page 13-8 of the Yanmar Service Manual for models 1GM 10, 2GM20, 3GM30, and 3HM35 engines. Thanks
High Pressure side of the system.
Pete: I think John is going by the book on this procedure. I would have to agree with you. You NORMALLY do not need to bleed the injector to start you engine. The book does explain the procedure to do this though. So John, have you tried starting the engine without bleeding the injectors?
Pete: I think John is going by the book on this procedure. I would have to agree with you. You NORMALLY do not need to bleed the injector to start you engine. The book does explain the procedure to do this though. So John, have you tried starting the engine without bleeding the injectors?
Agree with Pete
I agree with Pete, I've bled the lines in my diesel several times and never needed to do more than remove the little bolt on the forward portion of the engine. Probably not an approved way, but if the rest of the line is bled, I've decompressed the engine and cranked it for two or three seconds, fuel spurts. I also installed a hand bulb on my line from the tank to my Racor filter. One of those squeeze things used between a gasoline outboard motor and the fuel tank in a dingy. Speeds up bleeding the engine considerably.
I agree with Pete, I've bled the lines in my diesel several times and never needed to do more than remove the little bolt on the forward portion of the engine. Probably not an approved way, but if the rest of the line is bled, I've decompressed the engine and cranked it for two or three seconds, fuel spurts. I also installed a hand bulb on my line from the tank to my Racor filter. One of those squeeze things used between a gasoline outboard motor and the fuel tank in a dingy. Speeds up bleeding the engine considerably.
One more queation for Pete
Pete wrote "You should be able to start you engine with out bleading the injectors.If you have blead the filters (you most likely have two) then blead the fuel injector punp (it is a 10mm screw type bleader)With the injector pump blead it should start the engine with out bleading the injectors." This sounds good to me Pete. Sometimes the instructions in the manual overcomplicate things. Could you go over the steps for bleeding the filters. Thanks
Pete wrote "You should be able to start you engine with out bleading the injectors.If you have blead the filters (you most likely have two) then blead the fuel injector punp (it is a 10mm screw type bleader)With the injector pump blead it should start the engine with out bleading the injectors." This sounds good to me Pete. Sometimes the instructions in the manual overcomplicate things. Could you go over the steps for bleeding the filters. Thanks
bleading air 3GM30
John, Bleading the fuel system is relatively easy AFTER you have done it once or twice.First let me suggest that you get some help from someone who has done it and can show you how to do it. If no help available let me first say I don't know what your filter setup is. Most have a in line filter first (racor?) and a engine mounted filter.Most cartridge(in line)filters have a vent on top to blead air out.(this should blead out by gravity)next blead the filter on the engine.Use the manual fuel pump (lever on fuel pump)to blead this filter pumping fuel until no air exits (only fuel) exits the bleader. This is a 10 mm screw type bleader located on the filter housing. The injector pump should have the same type bleader on it facing forward,pump the fuel pump manual lever until only fuel comes out and close bleader valve. There are some tricks to help, one is to prefill the filters with fuel so that you are not pumping so much.Be sure that you have turned the fuel back on(assuming you turned it off when changing filters)Stay AWAY(do NOT use)starting fluids (either)to help start the engine.Once you have fuel at the fuel pump it should push the fuel thru the injectors and you engine is started.It should start with in 10 seconds if not you have not got all the air out of the system.This sounds more intimitating then it is.Good Luck! Let us know how you make out!
John, Bleading the fuel system is relatively easy AFTER you have done it once or twice.First let me suggest that you get some help from someone who has done it and can show you how to do it. If no help available let me first say I don't know what your filter setup is. Most have a in line filter first (racor?) and a engine mounted filter.Most cartridge(in line)filters have a vent on top to blead air out.(this should blead out by gravity)next blead the filter on the engine.Use the manual fuel pump (lever on fuel pump)to blead this filter pumping fuel until no air exits (only fuel) exits the bleader. This is a 10 mm screw type bleader located on the filter housing. The injector pump should have the same type bleader on it facing forward,pump the fuel pump manual lever until only fuel comes out and close bleader valve. There are some tricks to help, one is to prefill the filters with fuel so that you are not pumping so much.Be sure that you have turned the fuel back on(assuming you turned it off when changing filters)Stay AWAY(do NOT use)starting fluids (either)to help start the engine.Once you have fuel at the fuel pump it should push the fuel thru the injectors and you engine is started.It should start with in 10 seconds if not you have not got all the air out of the system.This sounds more intimitating then it is.Good Luck! Let us know how you make out!
Bleeding your fuel lines
John, here's something I hope will be helpful. Chesapeake Marine engines at 410-269-1903. I can't rave enough about these guys. I had the same problem with my 2GM20 (minus the rounded nut)and these guys talked me through it over the phone. The first thing they said to me was " the manual leaves out a step....". You shouldn't ever have to bleed the high pressure side unless you've been starved of fuel, either by a clog in the line, or a bad air leak on the suction side. I've had both. As for the rounded nut, have you tried slipping a lengthy pipe over vice-grips for increased leverage? I hope some of this helps, I've been there!
John, here's something I hope will be helpful. Chesapeake Marine engines at 410-269-1903. I can't rave enough about these guys. I had the same problem with my 2GM20 (minus the rounded nut)and these guys talked me through it over the phone. The first thing they said to me was " the manual leaves out a step....". You shouldn't ever have to bleed the high pressure side unless you've been starved of fuel, either by a clog in the line, or a bad air leak on the suction side. I've had both. As for the rounded nut, have you tried slipping a lengthy pipe over vice-grips for increased leverage? I hope some of this helps, I've been there!
Answered Your Question Earlier Today
John, On the Big Boats forum is a series titled Changing the Raw Water Impeller. As part of that discussion, the question of how to bleed the diesel came up. I wrote a step by step process to get that done. Go over there and give it a look. I think (hope) that it will answer your questions. I also agree, I don't think you need to bleed the high pressure lines. That would be unusual. I think you will find that once you have gotten the air out of the filters, the lines, and the top of the injection pump, the diesel will fire right up.
John, On the Big Boats forum is a series titled Changing the Raw Water Impeller. As part of that discussion, the question of how to bleed the diesel came up. I wrote a step by step process to get that done. Go over there and give it a look. I think (hope) that it will answer your questions. I also agree, I don't think you need to bleed the high pressure lines. That would be unusual. I think you will find that once you have gotten the air out of the filters, the lines, and the top of the injection pump, the diesel will fire right up.
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