Early 190XT Block Heater Install Results

I am reporting back on my block heater install.  I finally got a block heater in my early 190XT and it doesn't leak! Here's the long sordid details of what should have been a simple job.
 
I ended up using a ZeroStart block heater 310-0013 model.  On a previous thread, I described using a Katz model that would not seal.  I want to point out that neither of these manufacturers listed either model I tried as being compatible with the 190XT.  So, I can't blame either for a bad fit. 

Here are the details:

Deinstallation of the core plug:

1) I had to remove the side panel, disconnect the oil line and push it upwards and disconnect the fuel line in order to get room to remove the rear core plug above the starter.

2) Drilled a hole in the center of core plug and tried to use a core plug uninstaller that "screws" into the plug, then pulls it out.  The plug was in so tight, the screw stripped and the uninstaller tool was useless.  Don't spend $9 to buy one.  In theory, it should have been the way to go.  See below pic.

3) Now that I had a hole in my core plug, I had to install a block heater or reinstall a new plug.  I wasn't going to let this thing whip me, so onward with the block heater.

4) I tried prying the plug but the hole had to be elongated to get a pry bar into it.  I eventually made a huge hole and it still wouldn't come out.  I stuck a heavy duty punch into the hole as a pry bar and used a small sledge to hit the top of the punch towards the engine to force the bottom of the plug out.  After many, many strikes, it finally came loose, even though I almost cut it in half.  You can see the result in the picture below. 



Installation of the core plug:

1) The outer diameter of the casting hole is not 1 1/4 inches, but not quite 1 3/8 inches.  This is why the 1 1/4 versions don't fit tight.  This is also why a larger diameter O-ring must be used and sealant.  I purchased a 1/8 inch cross section thickness O-ring and replaced the 3/32 O-ring used on the Zerostart.

2) The inside lip of the casting hole is oblong on my engine.  The wing nut could not be inserted into the opening of hole, it was too small.  I had to carve out two spots in the casting hole slightly below center because the wing nut is not in the center of the block heater either.  I used a drill and chipped out two notches for the wing nut to slide by.  See picture below.

3) As a pre-test, I removed the wing nut and pressed the block heater into the casting hole to make sure it fitted flush to the outside.  Only the Zerostart would fit flush.  The Katz would "rock" in the hole which is why it leaked, even with sealant.  I believe that the rocking occurred because of the thickness of the plug part of the heater.  Also the heating elements seemed to touch the sides of the hole on the Katz, particularly when tightened.

4) After making the notches for the wing nut, I spread High Heat RTV silicone around the block heater and the casting hole and waited about 15 minutes for it to start to air dry.  I then stuck the block heater in, twisted it 45 degress towards the front such that the element was at the 2 O'Clock position then tightened it down.  I did not fully tighten it.  I waited about an hour, then tightened to give the silicone time to dry.  I then waited a full 24 hours and gave it a half twist to finish tightening it.

5) No leaks, after sitting over night.  I also started the engine to ensure I had no air pockets, and ran for 20 minutes and no leaks.  I then plugged it in for a few hours and it got nice and hot and no leaks.  I left it plugged in over night and no leaks.  Next morning, 190Xt fired up on first crank and it was about 35 degrees.

Notes on this situation:

1) The Katz and the Zerostart have the heating element oriented a full 180 degrees in difference.  See below.   For my engine and oblong casting hole, the Zerostart fit better.   For my 190XT, the Katz wasn't a good fit, but it could be a better fit for some other models.  Both are 600 Watts.  I don't want to knock Katz but in my situation, it didn't work.  Katz never claimed to work on my early 190XT either.  Without the bigger O-ring and sealant, I don't think the Zerostart would have worked because it had too much movement side-to-side when inserted in the hole.  The thinner plug body allowed it to sit tight against the block though.  I forgot to take a picture of the Zerostart before installing but here are the two.  First picture is the Katz.  Notice the thicker O Ring I used.





2) It seems to me that the Block heater is better in heating up the engine than a circulating tank heater.  I have a circulating heater on one of my other tractors and this block heater heats up much faster.  Of course, the installation of the circulating heater was much less stressful.

3) This has never happened to me before but the first Zerostart heater I bought on Amazon was claimed to have been shipped to me, but after 5 days, they cancelled the order.   I then reordered from the same seller, and it showed up.  I lost 10 days waiting on it though.

I hope my details above helps the next guy and glad this is finally over.  Of course, the really cold days are past me now, but I am ready for next year!  Thanks to all of those that chimed in and helped with guidance and/or moral support.