Have a bent push rod.I replaced it but can't adjust the clearance because the travel of the push rod is more than the valve will allow.

I believe you want Kohler SV7xx / SV8xx on Craftsman.
http://kohlerengines.com/engines/onlinecatalog/pdf/sm_32_690_01.pdf


2. Rotate crankshaft to establish TDC on compression
stroke for cylinder 1.
Check for:
a. Compression will be felt through spark plug hole.
b. Keyway of crankshaft will be aligned with cylinder
1.
c. No rocker arm/push rod movement if crankshaft
is rotated slightly back and forth. If they are
moving, rotate crankshaft 1 full revolution.
3. Insert a 0.127 mm (0.005 in.) feeler gauge between
end of 1 valve and rocker arm. Turn adjuster or
adjustment nut (based on design), until a slight drag
is felt. Hold in this position and tighten locking nut or
setscrew securely. Torque setscrew to 7.9 N·m
(70 in. lb.). After tightening recheck adjustment.
Proper valve clearance is 0.101/0.152 mm
(0.004/0.006 in.).
4. Repeat procedure for other valve on side 1.
5. Viewed from PTO end, rotate crankshaft 270° (3/4
turn) counterclockwise and align crankshaft keyway
with cylinder 2, which now puts cylinder at TDC on
compression stroke.
6. Repeat steps 3-4 for setting valve clearance on side
2.
7. Rotate crankshaft to check for free operation of
valve train. Check for clearance between valve
spring coils at full lift, or bending of push rod(s) can
occur. Minimum allowable clearance is 0.25 mm
(0.010 in.).

some engines have different length rods for inlet and exhaust
you have to set the correct valve clearance because if you don't the travel exceeds the spring length and so that bends the rods
you are well advised to get a workshop manual for the engine you are messing with

have you got the correct push rods under the right rockers
some engines have different lengths for each valve

Here's some generic answers, not relating to this engine specifically:

• The timing could be off, so the piston is hitting the valve.
• A loose pin in the piston could be allowing it to extend too far, shoving on the valve.
• I guess the valves could need to be adjusted so there's a gap.

Hi, had it been sitting some time unused?
Sounds like the valves are stuck in their seats and the rods bent when the motor pushed them with the cam.
You might be lucky and the one that fell in didn't get into the works.
Make sure you fish it out before doing anything else.
I'm guessing it is the typical side valve type motor?
Remove the valve cover (I guess you have already to get the push rod out) and using some sort of lever try and move the valves up against against their springs. Don't bend them with sideways pressure though. If they're stuck some CRC / WD40/oil or similar will help to get them moving. Remove the spark plug and spray CRC etc onto the valve heads inside the cylinder.
Assuming the push rod hasn't contacted anything moving while the motor was being wound over and done more damage, you should be good to go with new push / 2nd hand push rods. Just check there is some clearance between the push rod and the valve stem when each valve is closed.

turn the crank shaft and watch the relationship between the piston position and the cam followers. As the piston nears top dead centre you will see the exhaust cam follower start to move down and the inlet cam follower start to rise up. This will create a rocking motion of the cam followers at top dead centre. This is known as valve overlap assemble the motor in this position. Ensure the valve clearance is backed right off Turn the crank shaft one full revolution and you now have the compression stroke . This places the piston again on TDC and it is at this position you adjust the valve clearance. Check that clearance for the tappets as most engines run .010" and .012"tappet clearance. If the head is fitted last place the push rods in the cam followers if you cannot see the cam followers and it does the same job. When the top of the push rods reach the overlap situation it is just an extension of the cam followers.

sounds like the valve is binding in the valve guide

Usually there is a reason why the rocker arm came off the push rod so you will need to check a few things before putting it back together. First make sure the push rod is not bent, if it is replace it, do not try to straighten it. Make sure the rocker arm stud did not loosen, if it did back out, re-tighten. If you're ready to put it back together, you will need to set the valve clearance between the rocker arm and the push rod. You will need to know the engine model number to get this clearance since it varies. Once you get the clearance values, make sure the piston is at TDC on a compression stroke and adjust the valves per the setting. In some rare instances, the valve can "stick" in the valve guide and this will cause excessive gap. However, usually when this occurs the engine will not start anyway. Hope this gets you in the right direction.

I think you have the rocker arm clearance set wrong on the one that you worked on.
See if this video will help -

Lawn Mower Repair Valve Adjustment Twin

The push rod should just go back in where the broken one was. They set into the tappet almost automatically. You can slowly spin it over to verify. I'd replace both push rods if it where mine.
This is a generic OHV " How to adjust the Valves" YouTube video which should take you thru the process.
Change the oil. Check/adjust the valve clearance at least yearly.

How to Adjust Valves on OHV Small Engines Valve Clearance lash