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NC Wayne
09-21-2005 22:08:08
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Re: 371 Detriot Questions/HELP... in reply to Beakeeper, 09-20-2005 04:00:10
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Hey Beakeeper, I'm not sure from what your saying if you've actually had it running or wether your still trying to get it to run. I say this because in one place you say it starts on ether and revs up then dies, but in another you talk about it smoking when running (possibly what is was doing when initially parked years ago) ???? So I'll adress everything as well as I can and hope I cover what you need. Like the others have said the spring loaded lever that goes into the intake snorkle is an emergency shutdown. It's main use is to shut the engine down if the rack shutdown doesn't work, or, God forbid, you choke the machine down and the engine restarts running backwards. I don't know what the other knob is for. A 71 series Detroit shuts down by utilizing the rack to destroke all of the injectors to a zero fuel position. If you were to try shutting it down with a soleniod/mechanical valve on the fuel line going to the injectors the engine would continue running til it ran out the fuel already in the lines to the injectors as well as in the injector bodies. When the fuel in the injector bodies was gone the injectors would be running with no lubrication. Running out of fuel on occasion usually doesn't cause a problem, but doing it on a continual basis to actually shut the engine down would cause alot of premature wear to the injectors as well as making the engine take an indeterminate amount of time to actually shut down. If the second knob is for something like this you need to get rid of it. As for it being for some type of primer pump, etc I doubt that too. A Detroit utilizes a gear type, positive displacement fuel pump driven off one end of the blower. So no primer pump should ever be needed as the pump is self priming. Your right on the fact that there is a return line also. The fuel flowes into a passage in the head (or in external pipes on the really old designs) and from there through "external"lines under the valve cover and then into each injector body. From the injector what fuel doesn't get used, which is the majority of it, is returned to back to passages in the head, through a orifice which keeps pressure on the injectors, and then out through external piping back to the tank. Look for the lines screwed into the head on the opposite side from the exhaust and those are gonna be your fuel lines. As far as the rack being stuck if you can start the engine and it will go completely through the speed range from low idle to top end and back then the rack isn't stuck. The "rack sticking" usually isn't the actual rack at all, but a plunger in one of the injectors sticking. The amount of effective stroke each individual injector takes is "timed" by adjustments on the rack so they are all equal. So when one plunger sticks all of the others are tied to it via the rack so they are all held in the same position When a plunger sticks the engine, typically, will only run at one set speed. Rarely it will rev up or idle down from that stuck position, but not both. On the subject of the smoke, a Detroit has two oil control rings at the bottom of the piston that have almost a razor edge. After setting 10 years I'd just about bet at least one or more of them are stuck. OK, going on the assumption you haven't actually had it running yet. With a shot of ether the engine will rev wide open, til the ether is gone, and then die just like your saying. First, find the two fuel lines I talked about earlier. Unhook the return line (the one not coming through the pump), spin the engine over and make sure your indeed getting fuel to the injectors. Now assuming you have a fuel flow look for the lever on the governor housing where the throttle hooks up. Unhook the throttle cable/rod and make sure it has a full range of motion. It may be something has the throttle stuck in the shutdown position, so check to make sure the rod is moving. Look at which way the rod/cable moves the lever when you push the peddle to the floor. Make sure the lever on the governor is going all the way in the same direction also. Now holding the governor lever in a position where you know it should have fuel try starting it again and see if you get any smoke at all. You should get at least some smoke if your getting any fuel at all. If your not seeing anything and the engine still isn't starting, then pull the valve cover and move the rack by hand and insure the geared shafts the rack connects to on all three injectors are all moving in and out completely. All the way in is full fuel, all the way back is no fuel/shutdown position. If one or more of the injectors is stuck then go ahead and replace all three. If you don't the new injector/s will "fire stronger" than the old ones and cause an imbalance in the load between the three cylinders which isn't good for the engine. If none of this works feel free to contact me direct at--- Nota55Nomad@AOL.com--- and I'll be happy to help you troubleshoot as much as I can without actually being able to see it. Good luck. Wayne
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