B7100 misfire

[Kingcrabb]

Hello all!
Just picked up my second kubota. Got a bx25backhoe and decided I needed a second piece of orange machinery!
I acquired this b7100 in a trade for virtually nothing. It’s been sitting outside for probably most its life and hasn’t ran the last couple years.
changed fluids, and filters an got it running. Idles and low speed is perfect. But when I run it up past half throttle it starts to misfire. No blow by coming from breather and no oily smelling exhaust but it is shooting out White/grey fuel smoke every misfire.
I adjusted the valves and didn’t help any (some where too tight and thought it was hanging a valve open).
is there a chance the injectors them selves could be bad? They seem pretty cheap on eBay. Thoughts?

 

[johnjk]

Did you compression test the cylinders? It is possible you have an injector not performing correctly

 

[Kingcrabb]

I have not done a compression test yet. I’m assuming I would just remove the injector and thread in my adaptor. I have a compression test kit. Not sure what adaptors are in there tho.
I also figured since there is virtually no blow by that the compression was likely to be ok.

 

[Russell King]

I have not heard anything good about the cheap injectors.

The OEM or good aftermarket (Oregon Fuel Injection) are probably a better choice and I would recommend changing them all or having them all repaired.

 

[Kingcrabb]

I can’t find anything on google for those injectors. I found the website but not the Injector. I thought about cleaning my current injectors and going from there first.

 

[North Idaho Wolfman]

You could try cleaning them, but it's almost always a lost cause.
Just get new ones.

NEW INJECTOR, KUBOTA 15271-53020

IXC093500-1570

oregonfuelinjection.com

The other issue it could be fuel pump related, that gets into a whole other issue.
If it's starting good, then it's very unlikely to be compression issue.

 

[Kingcrabb]

Did a compression test the best way I could. I didn’t have an adaptor that thread in and sealed so I used the universal rubber tipped end and got 270,270,300 (cold). It fires right up almost instantly but doesn’t always stay idling the first time. Once warm it fires right up and idles perfect. Running at full bore using a temp gun the forward cylinder seems to be consistently 20° cooler than the middle and back cylinder.
I have injectors coming tomorrow, I’ll start there and hope the pump is ok. Other than the slight misfire and little smoke it seems to be doing ok.