more Kubota woes

I've gotten great advice and have my L185 running but now the #1 injector keeps pumping air. #2 is fine, I've bled lines but it keeps blowing bubbles. My fear is the pump is bad any advice would be appreciated.

Where would air enter, even if the pump is bad? Still sounds like an air leak before the pump or just still need bleeding.

There is two real easy ways to figure out what is going on. Click on my e mail and send me an email with a phone number and I will talk you thru it. jm.

If an injector is stuck open, every time the piston comes up on the compression stroke it pumps air back into the system. Doesn't happen too often, but I have seen it a couple of times in my career.

Weldingman, you were right. two new injectors but one was bad. JM, thanks for your phone call and walking me through how to test it. I put the old injector back in and no more bubbles. It still has a knock but not as bad as before. After reading more comments, it sounds like maybe these 2 cylinders may sound like this naturally. It also doesn't surge anymore, I'm assuming the injector would seal once and awhile and made it surge then stuck again.
This has been a long road to get the little L185 running. I've gotten great advice from YT and orange tractors. I'll give an outline of the journey since I've posted random questions for almost two years now.
I bought it not running, the man said he was told it needed injectors. I checked the pattern and it looked to be spraying correctly. Just couldn't get it to start. Sold it to my Son in law and he piddled for a year. Found a cracked land on one piston. A used piston and new rings. He ran out of time so sold it back to me. I put it back together and still would not start. To shorten story, after new injectors, new starter I finally found that the previous owner had plugged the hydraulic outlets on the block under the seat and had a dead block on hydraulic pressure. THe pump was holding back the engine so it couldn't start. After all this, I think I have a good running tractor now.HOPEFULLY nothing else shows up now.
I really appreciate all the knowledge on here and your willingness to share your knowledge.