Bleeding air at injector

[jslade8581]

So, I've been working on my sailboat's Yanmar 2GM since I got back from my last deployment, during which I stupidly did not winterize my boat's engine (there's a story there, but I picked my wife's birthday over my sailboat before I shipped out - crazy I know).

Anyway, I was able to get my engine to start, and it ran for about 10 minutes - then it stalled out. Based on some other posts I read and some info off the inter webs, I realized that I probably ran the secondary fuel filter dry. With it sitting for about 7 months, I figure the fuel flowed to the lowest point in the system.

I took advantage of the warmed up engine, and I changed the oil and then the fuel filters, then I started executing the bleed procedure by the tech manual, which got me through the secondary fuel filter to the inlet side of the high-pressure pump. It wouldn't start, and there were several bits of information that pointed me to breaking the fuel to the injector to bleed it by rolling the engine with the starter. I'm game...

But I can't break the line at the injector. The nut is solidly seized. It's pretty soft, and I am worried about rounding it off (especially after today). I was directed to some line wrenches, so I bought the size that I need. I was also directed to liquid wrench - but after two days of spraying it and letting it soak, no change.

PB Blaster was recommended to me today... By an auto mechanic. I realized that I didn't ask any fellow sailors - what do you think? Is there some trick to getting this nut off? Is it usually this hard to remove (as an aside, the return fuel bolt at the top of the injector came off no problem)?

The other thing that I'm trying to get at is the engine zincs - their covers are frozen solid too. And they have a wicked case of corrosion - that worries me...

Nick

[jrd22]

Blaster is good stuff, has worked when all others have failed for me. Must be a bad case of corrosion because they usually aren't that hard to break loose. Remember to close the raw water seacock if you are using the starter for prolonged times without it firing or you can dump water into the cylinders. Our old 3GM was pretty forgiving about not bleeding the injectors, can you use the hand pump and get fuel to the inj. pump bleed screw. It might just start up at that point without cracking the inj nut. I would guess that you plugged up one/both of the filters from gunk in the tank from sitting that long, did you use a biocide last time you filled up? Good luck, and thanks for your service.

[jzk]

You need to use a line wrench.

http://images.search.yahoo.com/image...9&fr=yfp-t-701

[jzk]

Oops, i see that you already tried that. The line wrench wont free it?

[jslade8581]

To answer both of the posts in order:

1. I did get fuel to injector pump bleed screw with the manual pump, and I didn't use a biocide then (I did add some already to see if that would help). The fuel is flowing readily, which is somewhat positive. But yes, I had a pretty bad case of corrosion. That is still a concern, I feel like I might have a seawater leak show itself once the engine is running...

2. I got the line wrench and pb blaster today, but the first time I'll use them will be tomorrow. I'll let you know if it works.

And thanks about the seacock - luckily I already knew about that or else I would have been screwed! The nice thing about the engine is how simple it is... Fuel and combustion. Since it ran, I'm positive that I have compression. Once the fuel gets to the injector, I'm sure I'll be able to go sailing again.

[INMA]

The thread on the nut sounds like it has been very tight to begin with then corrosion has made matters worse.

Injectors are fragile beasts so what I am about to suggest is an action of absolutely last resort.

Put a very heavy dolly held firmly on a flat of the nut then hit the other side of the nut with a small, repeat small hammer. The aim is to deliver a shock wave through the thread that will break the friction in the nut's thread.

Remember the injector is a precision fragile item so use care to have the dolly firmly in place before hitting the nut. If you can get at more than one set of flats even better.

It is harsh but impacts do things force does not achieve.

Heating the nut faces is another possibility but because you have diesel around I was reluctant to offer that alternative.

Is it possible to remove the injector with the line attached and take it to a work bench?

Reassemble it with some copper paste.

[WanderingStar]

If you do try heat, use low on the heat gun, or pour boiling water on the part.

[casey1999]

As far as the Zinc plugs, I also had problems, here is my fix:

I got the zinc plugs out of the 3GMD. I am not sure what helped the most but I think it was the propane torch. For one of the steel plugs that I stripped the head on I used an Irwin tool used to remove bolts with rounded heads. The Irwin tool looked like a socket but has a swirl inside that bites into the stripped head. The more torque you put the more it bites into the bolt. The tool worked great. I had a 4 foot pipe on my socket wrench handle with proably 150 lbs on it (600 ftxlb torque) and the bolt broke lose from the block. Irwin makes a lot of different extractors for all kinds of fasteners. Great tools.

First I used dry ice- hard to keep the ice on the bolt and it did not seem to cool the plug much. I did put PB blaster on but threads were so tight I do not think much got into them. I tried to remove plug but no luck. Then I used a micro torch as I was afarid of setting the boat on fire. Micro torch did not do much as flame too small. Then I used a plumbers type propane torch. Had a lot of fire extingishers armed and ready. Held the flame for a couple minutes as I was afarid of damaging engine gaskets. My IR thermometer showed The plug was about 160 deg F. It seemed the engine block was really sucking the heat. I then put the socket wrench to it with a 4 foot pipe extension and 150 lbs force. Somthing started to more- at first I though my Craftsman 3/8 inch socket wrench was stripping but it was the plug slowly turning. Both plugs came out this way. The threads actually looked great- no zincs left. Installed new plugs with zincs along with a lot of marine anti-sieze. Next time should be easier. You can buy the Irwin tools on line- the american made tools seem to do what they advertiser. You will need to convert the metric to whatever is closest in sae- I believe it was 5/8 inch.
Irwin 53910 5/8 Bolt Extractors | AceTool.com

They do have metric size:
http://www.acetoolonline.com/Irwin-B...ors-s/2819.htm

Note the extractor will destroy the bolt or plug you are removing- will need to install a new one, but chances are the old one is corroded and needs replacing anyway.

[jslade8581]

Well, I got down to the boat today, and I was able to get the injector line nuts off. One came off easy - two days of soaking Liquid Wrench did the trick. The second nut was pretty tough, but after a few more liberal applications of the Liquid Wrench (never did use the PB Blaster), it came free.

To bleed the injector lines, I took one nut off, then my friend started the engine. As soon as I saw a little fuel seep out (not a lot), I had him stop (it took maybe 2-4 seconds of running the starter). Then I tightened the nut and moved to the second cylinder and did the same thing. Once I was done, we attempted to start the engine, and it didn't start.

The starter was definitely rolling the engine, and the were a few times I could hear one cylinder firing, but the engine didn't start. I checked the air horn again - no blockage. The manual fuel stop was in the run position (i.e., I manually disconnected it to make sure I had the full range of play). I had the controls set up with the engine out of gear and max fuel.

I don't know what it is now.

If the engine at least started, then died after around 10 minutes, I would assume bad fuel since that would be me running the secondary fuel filter dry - but I see nothing but clean fuel come out of all of the bleed screws and the injector lines. And it won't start.

I can't imagine its compression, because the engine started five days ago and ran for 10 minutes before it died. That tells me that I had compression for some period of time (those 10 minutes).

Should I run it longer with the injector line nuts off? How much fuel should I see coming out of there? To me, if I see fuel (and it was a little, maybe enough to put a quarter sized fuel stain on the paper towel I was using) then I should be good. The fuel didn't look whitish, but did I not run it long enough?

Thanks again for all of your help.

(As for the Zincs, I'm still letting them soak in Liquid Wrench - I can't say I'm terribly excited about bringing a torch onto the boat!)

Nick

[INMA]

Try Arostart or one of the ether products that spray in the air intake.

It could be lack of compression due to damaged rings and bores.

A compression test is probably justified.