Just put a block of wood on the back, and another block on the front to protect the shaft, and put it in a vice. Once the tapered collet and drive spool come loose, it will come right out. Sometimes they are stuck so tight you have to heat it with a heat gun a little, to help it along. At least it works for me.

If you can , pour boiling water , on the prop drive spool , or hit it with propane torch.

The expansion should see it remove itself . Save the big ammer  . BEARINGS side loading

isnt nesesarily conducive to there well being .


CLEAN the collet thourougly in thinners before refitting ,

Black grime in that area can allow the prop to rotate till the spool goes 'ping' on retightening with the 12 " shifter !

You can use a small gear puller on the thrust washer (no impact to damage the bearing).  Then the crankshaft should come out with a slight tap on the end, unless it's full of dried oil.  In that case, heat it slightly with a torch and it should come out easily with a couple taps on the end with a plastic hammer.

Fred

Or set the engine on a flat pan in the oven once you have removed the drive washer (I got an OS drive washer puller from Tower).  Put the oven on about 400 degrees, and you will hear the crankshaft drop onto the pan.

Big Bear

Rubber mallets suck. They don't ever do much moving of the part, but you might just get it in the forehead on the rebound, or give yourself elbow problems. Get a good plastic mallet, or just use a block of wood and whack it with any suitable steel hammer you have handy. Just because the hammer is big doesn't mean you have to swing it like you're killing snakes.  Steve

Would you have a glare at the bearings , and tell us where there Mnfgd . Botswana etc ?

Might need an eye glass . Which are fairly usefull for looking highly technical !

If the bearing is removed, scan it at high resolution to read the numbers.

You can't use a gear puller on the ST drive washer because there's nothing to grip. There's a very thin lip that goes over a machined portion of the crankcase and that's about it, the rest is flat. Heating the drive washer and pressing is about the only way to get it off.

   I use a battery terminal puller with no issues. I did grind it to have a curved end and a sharp edge, but there's enough to grip it with.

      Brett

You know I never responded to this thread, and I was the one who started it.  The mallet worked just fine, the crank came out after a few good hits.  Since then then the bearing were replaced and the ring was replaced and the engine runs better than ever.  A friend came up to me last Sunday and reminded me of this thread and asked me what I thought of the  ST .51.  Well out of the box I think the the control line version is a very good engine.  Since running the engine with the new ring I would say change the ring at the git go.  The new bearings are good, but there is no noticeable change in performance.  I really like the ST .51 and would recommend this engine for use where it's weight is not a problem.  I am running the Chinese version and cannot see any reason why this is not as good as the Italian version.  Maybe the ring on the Italian was better but I have no way to prove that.  Frank Bowman will size and install a new and better ring for a very reasonable cost.  Should I get another ST .51 I would have the ring changed out before using it.
Andy