deuce injector leak

Prescott, AZ
I watched the videos on this thread and was surprised to find other deuces start right up in the cold better than mine does on a hot day. I typically have to crank it several times for long cracks to get it to start.

I have also noticed that it has one or more leaking injectors, which might explain the difficult start. So, I searched here for a source of injector seals, if there are any. Can anyone help me locate the seals, if they exist. I have an M756 A2 non-turbo. It also has some leaky injector hard pipes, so locating replacement injector hard pipes for it would be useful as well.


Steel Soldiers Supporter
Cincy Ohio
The actual injector is leaking?
When I first built my deuce, it would start right up. Years later, when I did head gaskets, I also pulled the injectors and pop tested them. I don't think even ONE popped over 200psi. A good set is supposed to pop around 2800psi(for take-outs). I ended up finding some new injectors and putting them in. It fires up MUCH better now.

You should have your injectors rebuilt at a shop.


Active member
Steel Soldiers Supporter
Milford / Michigan
I would love to have an M756A2 :D

Anyway, I am with gimpy on this one. I did get a set of take out injectors for my truck that were a newer style and they pop off at 3400 PSI. I'm not sure which is better and all, but i have heard the newer style pop off at a higher pressure. if you look in the bosch manual for these injectors it says they pop off at around 3500 i believe. This is a lot higher than the manual suggests. Another thing to look at and do is to adjust your valves. I am big on preventative maintenance and think that can help a lot. You can also check your timing and make sure it is set to the correct setting. Those are just some basic things that may help you also and they do not cost much money. I hope this helps.


Well-known member
There is a copper crush washer at the bottom of the injector shaft which seals to the combustion chamber, if that was leaking you would most likely hear a compression leak.
There are fat rubber seals under the injector heads (usually red in color),those seal out debris from the hole the injector goes gown into and have nothing to do with sealing compression or fuel.
Your hard line connections can be tightened, if there are leaks in your plastic lines it could cause loss of prime.
If you have leaking injectors into the combustion chambers because the injectors are worn out or need adjustment, this can burn a hole in a piston!
The copper crush washers can be had from any injection pump rebuild shop.
Last edited:
Prescott, AZ
Thanks all for the input. Yes, rayzer, my return lines are also leaking. So, I am just going to have to do a complete work over on the fuel system to stamp out the leaks, and improve injection, thus improve starting and mileage. It only gets about 5mpg right now.
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