Ring Mount and Waterpump

We bolted the Rotax ring mount to the engine, which was a bit more challenging than we initially thought it would be.  We had to remove the waterpump and a few hoses first.  And lining up a few of the the bolt holes, which are hard to access, while inserting tight washers was some fun, too.  But we managed to get the ring mount installed and torqued down to the engine.

Ring mount (white) installed

However, we had another surprise when we went to put the waterpump back on.  The inlet/outlet ports on the left side of the waterpump now interfered with the freshly installed ring mount.  So we called our Rotax Rep (Lockwood Aviation), and they confirmed that the engine as shipped from the factory did not have the correct outlet port configuration for use with the ring mount.  We needed a 20 degree elbow on the top left port, and the lower left port elbow needed to be rotated.  We ordered new elbows and a new waterpump gasket and waited for parts again.

Removing the two elbows on the left side of the waterpump was not trivial.  They have to be heated to at least 80 degrees C, and then rotated carefuly so as not to damage anything.  The waterpump is aluminum and works like a good heatsink.  We couldn't get the temperature quite hot enough with 1 heat gun, but we had a 2nd one on hand, and with 2 heat guns we were able to get it hot enough (The heat softens the locktite that is used to seal and hold the elbows in place).  Once the elbows were off, we cleaned the threads.

When the new parts arrived in the mail, we screwed on the new elbows temporarily until we could get them lined up properly.  We put the waterpump back on and rotated the elbows until we had them in the correct position, then we marked the position with a sharpie.  We removed the waterpump and elbows, applied a good coating of green locktite on the elbow threads (as recommended by Lockwood), and then screwed them back into place until they were lined up with the sharpie marks.  Then we let it sit for over 24 hours so it could cure.

Waterpump housing with 2 new elbows installed

We installed the waterpump with a new gasket, and then installed the coolant hoses.  It all looks good now, so we can move forward with the engine installation. Hours: 15

Ed installing the waterpump

Michael installing coolant hoses