941 diesel questions

scott2013

Member
I bought a 941 a few months ago and have been working on repairing things as I find them. The engine will start and run good but I found fuel in the oil pan. I read through several posts on this issue and decided to start with the injector return line under the valve cover. I found the fitting that turns back into the head was not even finger tight (pic). I tightened this but it bottomed out. Is this normal or should there be a compression fitting around the pipe? Also, the stand pipe on the tank return fitting is gone. I was planning on soldering a piece of copper tubing back in the fitting and have it extend up to the top of the tank. Is this correct? Any feed back/comments are appreciated.

Scott
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The short tube that goes into the head is straight- no flare. I am sure that a rubber compression ring (lots of guys call them "olives") fits over the tube and the nut compresses it sealing the tube-head junction.
I doubt that you can solder in a new standpipe because that Tee Fitting is one huge chunk of brass and would soak up all of the heat. Maybe you could preheat it an oven and then solder in a tube but you need to confirm the passageways through that Tee first. The pump return line and the injector return line both dump excess fuel into the Tee. The injector return goes up through the standpipe and if I recall correctly the pump return fuel exits at the base of the standpipe. You could possibly plug the pump return ports with solder. Use compressed air to confirm the passageways.
 
Thanks for the reply Texas! I pulled the return pipe and checked for the seal. It was in place so I reinstalled everything. It appears that the nut compresses the seal around the down pipe to prevent leak by. On the fuel return block there are 2 inputs and 1 output. The passage (very small) for the injector leak off return was blocked so I took a pin (sewing) and cleared the blockage. This doesn't match your description of separate outputs so I'm wondering if I have the wrong Tee. I'll use it anyway for now as is. With the fitting tightened and the passage clear it will work better than before.

Thanks,

Scott
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I don't think you understand how it works. The injector return line connects to the bottom of the Tee and is connected internally to the standpipe so excess fuel goes up the standpipe and overflows into the tank. The standpipe is only 1/8" O.D. and the hole in the threaded end of the Tee is 1/4" I.D. (approximate measurements). The pump return line connects to the side of the Tee and exits through the gap between the brass fitting and the standpipe. The injector and pump returns are NOT interconnected inside the Tee. For some reason unknown to me (I suppose the RoosaMaster engineer knew why) the pump will have "head pressure" in the return line anytime there is fuel in the tank. The standpipe goes all the way to the top of the tank so there is no "head pressure" in the injector return line.
The photo is looking down the standpipe to the brass Tee. This is the only Tee I've ever seen (out of 8 or 10) that still has the standpipe in place. Apparently the vibration of the diesel engine shakes the standpipe loose. I assume it was just a press fit- no solder.
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OK, I got now. I understand why you said soldering a new pipe in place would be a problem. I wonder if red loctite would hold the pipe in place? I'll have to experiment.

Thanks for the info and pic!

Scott
 
Just an update to complete this thread. I didn't have any red Loctite so I used some epoxy to glue the tube in place. It seems to be holding tight but until I get it running I won't know for sure. The original tube was in the tank but I had already glued a replacement in so now I have a spare.

Scott
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