I am new to the game and all players are new to me.

Me: 290
Button: 125
BB 500
CO 1700

I only have seen couple of showdowns by CO and one hand CO calls 2nd in with J6s at LP vs EP 25 open.

I open LJ with AA to 20. CO, Button and BB call.

Flop: JJ4

I c-bet 40, CO calls, Button raises all-in, and BB folds. My SPR is less than 1 at the point...an easy call to me if CO isn't in the pot. What is our plan now?

You only have 230 left, the pots 400, and he could have a FD in his range...I would call it off here. Not happy that you block FD's but if he has a jack you have a couple outs. I wouldn't really blame you for folding either and I'm not worried about the CO flatting you otf.

The CO has all JX in his range, besides smaller prs and FDs, so a BTN raise after his call looks like strength, especially in light of our holding the As. I'd fold.

Flop - this is a great spot for balancing our Xing range, since we don't need much protection, and are OOP to 2 others.

On your stack, if you raise 4x you can only open a small number of hands. I'd rather raise to say 12 and open a much wider range.

On the flop, you don't have any business betting this flop for this size. In fact, I'd argue you don't have any business betting at all. If one player calls J6s vs EP 5x, then he has way, waay more Jx than you, as well as 44. You shouldn't even have KJo raising for this size, so that leaves you with KJs and AJ. It's not enough. If money piles in on this flop it's probably -EV for you. So check. Let your opponents feel their 4x might be good, let them hit a pair, let them protect with 55-TT. If it checks through and the turn comes a K, Q, or T, suddenly you are in a way more profitable situation.

Basically you shouldn't be in this -EV spot.

Dunno about OPs room but many 5/5 games only play the red $5 chips (or yellow in Commerce, for example). $1 chips often don’t play.

Agree that checking this combo of AA (blocking NFD) makes a lot of sense. Not doing it because I’m worried about any player holding Jx, but because I want my opponents to catch a pair on the turn. We’re only beat by Jx a small portion of the time, even 4ways, such that it isn’t really a concern IMO. At 3.5SPR we’re basically pot-committed to the hand, IOW we probably shouldn’t be doing a lot of folding unless there is obscene multi-way action.

+1