Hi Wyatt , if you think you have a few suspect pieces , can you snap them in half ? if so are they brown in side or black all the way though ?
If its only a odd few that seem not to have carbonised all the way through I wouldn’t over worry as long as the bulk of it all is all very well cooked you should be fine , I have been running engines now for around 3 years , most days during winter and maybe once or twice a week during bad days in summer and have never had a tar issue , in fact I have a cruncher that I made by accident so it stops turning as soon as a uncooked piece gets into the mix and after all this time that’s only happened a few times .
The one type of wood that does seem to be very hard though, and gives the uncooked impression is red gum and that is as hard as anything even when fully cooked through , so maybe you have some very good hardwood mixed in to your chips .
Dave
All my chips are charred, all are breakable by hand and black through, some are just not giving the broken glass sound and are both heavier and harder to snap than the majority of pieces. I expect I am being overly cautious after hearing stories about wood gasifiers running motors and then gumming them up.
In my pursuit of gasification I have gummed up 3 motors. It takes a “lot” of gum to really do any damage. Relax. Observe the overall quality and don’t worry about those questionable until the questionable becomes the majority.TomC
l have run a 2 stroke engine for on an updraft wood gasifier (makeing tar with traces of woodgas 
) in my early atemps and it run well for about 12 hours. Then the piston glued it self on the cilinder 
The point is tgings are not so fragile as one might think.
Not worrying about tar is one of the reasons I am enjoying running my Tracker on charcoal right now. With its valve interference engine, tars were always on my mind when I was running wood. At my age I don’t have the time or energy to tear into a tarred up engine although with my WK gasifier design, I never had any hint of making tar.
I am going to go with the consensus and stop worrying about the charcoal. Time to build and run something, the fair is in 10 days. I wish my Massey Harris Pony was operational. That would be an easy conversion for charcoal, one soft rad hose size pipe and two gear clamps.
So I decided the charcoal is probably ok as is so I thought I would cook the last two batches of a full 45 gallon drum of very dry wood chips. The second last batch had to be cooked twice, the first time all the wood did not burn and there was a high percentage of almost raw chips mixed in with the charcoal. Second baking fixed that but as I went to load the last batch of raw chips into the retort I poured in one pail of raw chips and then poured a half pail of finished charcoal on top. Not sure what my brain was thinking but that added 10 minutes to the job carefully pulling out handfuls of charcoal and then picking out individual raw wood chips from the finished pail. Have to remember to keep the two sets of pails more separated. Some days are just like that. I am now out of dry raw stock so I need to consider direct charring softwood brush and how to cut it easily. I would love to have a rebak or similar machine.