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1975 Unimog 416 Danish Troop Carrier
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144 Posts
Discussion Starter #1
Hi All,

My 416 is acting up, I am hoping it's just calling out for attention. Anyway here is what is happening: After sitting for a week or so, I go to start the Mog and she will fire right up and run for 5-10 seconds and die. Then when trying to re-start she will turn over and over and over and over, only too cough a few times, not enough the run or just cough along with the starter. Sometimes (most times) she will final start before the batteries die (kind of like trying to start in the really cold weather). The Batteries are good and the starter speed is good. Once started the Mog runs just fine with no excess smoke or loss of power. The Mog will re-start right up say if I go to Home Depot or something.

It's 24 volt
has 350 hrs and 31,000 KM
I drive the Mog at least once a month.


My thoughts are:
1. Air Leak in the Fuel system? But does it really take that long the suck the fuel to the injectors?

2. Injector over follow value sticking?

Any thoughts or ideas will be gratefully excepted and appreciated.

Thank you for your help,

Brian Heuschkel
1975 416 Cargo/Troop
 

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1978 Case 406
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173 Posts
Brian, try pumping the primer pump and see if that helps. If it helps, it could mean a air leak.
Bob
 

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Hey Brian, the same thing was happening to me. Turns out I had water in the fuel line. I replaced the fuel filters and everything was okay. I haven't had any problems since then. My fuel primer is located right were the little glass bowl is....I suspect it would be in the same area as yours. Good luck

Hans
 

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1978 416.115
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1,035 Posts
On top of the 2 fuel filters on the left side of the engine, there are 2 bleed screws.

Unscrew the front one and then reach back on the left side of the engine, there's a primer. You have to unscrew the primer and that lets you lift it up and down. Keep on pumping up and down until no air comes out of the screw and only diesel fuel.

Do the same for the back, and repeat again.

If you see bubbles coming out instead of diesel, that means you definitely have air in your system.

If you don't see any bubbles, not sure what else it might be.
 

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'78 Mog 416.141 DoKa
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I suspect it's an air leak - it happened to me once and turned out, in my case, to be one of the gaskets in the prefilters.

After sitting for a week or so, the truck would fire then quit - I had to use the primer pump and occasionally it was bad enough to require cracking the bleed screw on top of the filter housing. It was fine with short stops.

(edit) If it's a 'new style' primer pump, I don't think those unscrew...
 

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1978 416.115
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I suspect it's an air leak - it happened to me once and turned out, in my case, to be one of the gaskets in the prefilters.
The filter to the right of the diesel tank is re-known to suck in air. It's a little plastic bulb with a metal filter in it. The guy I bought my mog from said to get rid of it and put in an inline plastic filter as soon as I could. Eurotruck sells them, I think.

Also there's a loop thing on top of the diesel tank. If that is plugged, your system can't draw diesel from the tank and it'll sputter and die.
 

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mogless, except for my friends MB4-94. And a bunch of other diesel junk.
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2,512 Posts
everyone's right on, you've got air in the fuel line. Lots of ways to fix/ troubleshoot it.
 

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1975 Unimog 416 Danish Troop Carrier
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144 Posts
Discussion Starter #9
Thanks for the Info...

Thank you everyone, If it warms up a little this week-end I'll check it out.


Thanks again,

Brian Heuschkel
 
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