Knocking sound on D1005 that goes away with open injector line

[c5vettster]

Hi folks,
New poster here. I am getting a Kubota D1005 powered generator back to life after the pump injected dirt. The pump was rebuilt but now the engine makes a knocking sound that goes away if I crack open the injector line on the middle cylinder.
here is the youtube link

What do you think I deal with? Clearly the knocking goes away when I depressurize the cylinder. A bad injector or something more sinister?

 

[RBsingl]

A stuck open or badly leaking injector can make that sort of noise. Here is a pretty good example with "fuel knock" due to stuck injector:

Rodger

 

[c5vettster]

A stuck open or badly leaking injector can make that sort of noise. Here is a pretty good example with "fuel knock" due to stuck injector:

Rodger

You know I think that maybe it! I am going to put a new injector in

 

[RBsingl]

I hope that fixes it for you! Good luck.

Rodger

 

[mike0000]

If it‘s easy to do, swap injectors around and see if the knock moves too.
that should let you know it is the injector, not an issue with that cylinder.

Mike

 

[c5vettster]

A stuck open or badly leaking injector can make that sort of noise. Here is a pretty good example with "fuel knock" due to stuck injector:

Rodger

Thanks! It does look like this! I will change the injector and scope the cylinder this weekend

 

[c5vettster]

Well, thanks for all the advice! It was indeed an injector! I replaced it with a spare one that I knew was good and here how she runs now.

 

[RBsingl]

That sounds MUCH better! Glad it was a pretty cheap and easy repair!

Rodger

 

[c5vettster]

That sounds MUCH better! Glad it was a pretty cheap and easy repair!

Rodger

So am I. I knew it must have been something simple for these engines don't develop a deadly knock because it took 6 months to get the injection pump sorted out.