I raised with ( 2 5 ) 4 and got 2 callers. On 4th the boards were:

( 2 5 ) 4 K
( x x ) A K
( x x ) 2 5

The 2 5 bet I called and the A K folded. I hit a 3 and my opponent got a jack, check to me I bet, call. I catch a 9 my opponent gets a 7 he checks, I bet, call.

On the river I get a 7 he checks, I bet and he raises.

( 2 5 ) 4 K 3 9 ( 7 )
( x x ) 2 5 J 7 ( x )

I am pretty sure he made a 7 low but can't decide whether the right play is to raise or just call.

Well, there are 9 ways each he can have A3 or A4, which beat you. There are 9 ways he can have 34, which is a split. And there are 12 ways each he can have 6A, 63, and 64, all of which you beat. So you're 2:1 to have the best hand, assuming that your read is correct (which it probably is). Therefore, you should raise.

Ah putting it like that its a clear raise. I also think its unlikely he would check A-3 or A-4 in the hole on 5th street; it would be a pretty big mistake

I do think though that decisions like this are hard to make on the table though and thats why razz is so fun.

Is the call on fourth street correct? With the small pot, I would probably fold it there...

Actually I used to fold all the time if I bricked like this on 4th but when you still have a good draw like three cards to a 5 low folding is actually a big mistake. It was while watching the 2004 razz final table at the wsop I noticed that the on screen percentages showed even when one player hit a total brick on 4th like a K he would a lot of the time be only a 3-2 dog and getting 4-1 from the pot folding is clearly wrong. In razz remember that the very next card can flip the percentages or give one player significant lead when he was a dog.

You should typically continue until the river if you figure to have either the best hand or the best draw. So if on 6th you are double paired but have an 8 draw and your opponent has a made 10-9 with an open pair or paint you should definetely call because the pot will be big enough to justify it. If he had a board of 3-5-5-9 though then you shouldn't draw to a 10 because you could be drawing dead.

One interesting hand from the 2004 final table between Howard Lederer and T.J Cloutier. Short handed T.J opened bluffing with ( 10 J ) 2 and Howard called with ( A 2 ) 10.

Howard : ( A 2 ) 10 10
TJ: ( 10 J ) 2 K

TJ checked, Howard bet and T.J called. Howard is a 7-3 favourite but getting 3-1 on the pot T.J is right to call. The next card could go either way. Now T.J gets a 5 and Howard gets a 6. Check by T.J, Howard bet, call. Now on 6th street.

Howard : ( A 2 ) 10 10 6 6
TJ: ( 10 J ) 2 K 5 J

TJ bets and Howard raises. He has no made hand and is drawing to a 10 low but has correctly determined that he is a 2-1 favourite against TJ's K low. TJ can't bluff raise Howard because the board shows TJ's best made hand is a J low and the pot is now so big that Howard will call and draw to his 10 low and pay TJ off for one more bet on the river if he hits any hand. TJ is forced to concede "You're telling me you have the best draw eh?" and Howard amusingly points to his up cards and responds "How can this not be the best draw?". TJ calls, checks the river blind and Howard says "You're checking? Lets see here... and I made my 3 pair! Oh my god." TJ triuphantly responds "Good I have a K" and rakes the pot.

I thought it was a really instructive hand that shows some really close decisions on all streets. Folding is out of the question with the price the pot is offering but its fun to watch how each player tries to figure out if they had the best hand and get a raise or extra bet in at that point. TJ could have had a hand like 9-5 in the hole and played it this exact same way, in which case he would three bet Howard on 6th.

Folding when the pot offers a big price is every bit as bad as calling when you are clearly drawing very thin and in razz more than other games a lot of hands go to the river because often no one has a huge edge.

when you have good hands like that on 3rd, that's why you raise on 3rd. you want to be able to keep yourself in the hand on 4th if you brick.

if anything, you can fold on 5th, but it's worth a call on 4th to see 5th.

These two quotes are similar, and yet totally different.

I'm of the impression (from reading a few sources - there isn't that many of them out there) that had you raised on third (as HangukMiguk has stated), then your call after bricking on 4th may still be correct. However, since you did not raise, your call is most likely incorrect (I don't know the math here).

I did open for a raise on 3rd

Duly noted. Misread it when I posted. Ignore my rantings.