M4050 injector replacement

[tim_puckett87]

I have a M4050 that I noticed was leaking fuel from the threads around a couple injectors. I decided to just pull the injectors and replace with new one since its a fairly high hour engine anyways. The injectors just have a crush washer for a seal. I bought all new ones to go with the new injectors. After install of the new injectors I'm still getting fuel leaks from around the threads and on one it's pretty bad each time the piston comes up its pushing air and fuel out. I've never messed with injectors like this before, I'm mostly used to cat equipment that has 2 seals. Is there's supposed to be some other type of sealant on the threads of the injector? If anyone would know the torque specs for the injectors that would be great because I have looked for hours and haven't been able to find them? Any other insight as to what may be causing this? I don't think it's a cracked head but it is possible and I just can't see it.

 

[Captain13]

I wouldn’t think the fuel would be coming up from the head and bypassing the threads. Usually raw fuel would be leaking from above the injector, possible a cracked or loose fuel line. For it to come out of the head and up, the cylinder would have to have a significant amount of fuel in it. Of course, don’t feel around those lines when cranking or running the engine. I have deceased that are before on other engines, got it good and dry, then dusted it with baby powder and watched for the fuel trail to start.

I’m not discounting what you are seeing. With air being forced up from the cylinder past the threads, I would get some new crush washers, remove the injectors and look for any sign of carbon or damage that may be causing the washer not to seat and seal properly.