Time for new injectors?

'67 4020 powershift, hours and prior history unknown. I've had it for 11 years now and has been a good solid tractor. It probably gets used an average of 100 hours per year. Primarily used for running bat wing mower and moving hay bales and brush with the front end loader, so an alternate of high rpm work and low rpm work. Starts very easy, it is usually running almost immediately when you hit the starter. It has a moderate amount of blow-by. Minor oil consumption, probably a quart every 20 hours running. It has always smoked a little blue smoke, and I've noticed a little more smoke lately. I've not noticed any wet stacking.
The injection pump went out 3 years ago, and I had a re-manufactured JD pump installed at the local dealer.
I'm thinking that the problem is probably the injectors. I've never replaced injectors, but if Rachael can do it, surely I can too. How bad of a job is it? Do I need the injector puller tool? Any hints or cautions on the job? Any advice appreciated.

If no miss, knock, or white smoke, just a bit of an increase in blueish smoke, for 100 hour a year, I don't think you need to make a mad dash to replace the injectors just yet.

Check all aspects of air intake system, be sure that filter is clean and there's no dirt/debris/mud dauber nests restricting air flow.

How long since the thermostats have been replaced, does it warm up quickly and maintain temperature under load?

a diesel engine is to be worked. what you are doing is very light duty. things carbon up. it need 1/2 a day of good pulling in the field then monitor the situation. might be nothing wrong at all.

I would not jump into anything with that description, work it good more.

Getting out pencil injectors can be a horrible job. Sometimes they pull right out, and sometimes nothing will pull them out. I have had to pull a few cylinder-heads and drive them out from the other side a few times.

We had the special OTC puller at all the Deere dealerships I worked at and nobody ever used it. Using a good-quality "lady-foot" pry-bar that had a sharp edge that caught in the puller-grooves worked just as well.

I have no idea if injectors is your problem or not. I have done injector changes on a lot of Deere engines that were running fine, yet all the injectors tested bad.

In theory, the proper OTC slide-hammer puller that fits tight into the two puller-grooves is supposed to be best. Like I said, we did not use it since when we DID use it on very stuck injectors it just stripped those grooves out. The Snap-On lady-foot pry-bar is what worked for us. The same tool from Matco or Mac did not work. I bought mine 40 years ago from Snap-On and have no idea if they are still the same. From the photo, it looks like they are.

Make sure you use some anti-seize compound on new injectors if you put them in. It is amazing how stuck they can get.

Thanks to all who responded. I'm just watching it for now, but like to plan ahead on jobs like this to see if it is something I can do when the time comes, or plan on sending it to the shop. Especially appreciate the comments on how the special puller doesn't work that well.