Brief Description: Installed Tanis engine heater to my Rotax 912 is S
This should have been as simple as installing the 5 bolt heater elements (4 in the head and 1 in the case) but because the sport version moved the water temp sensor to the #4 cylinder head, it interfered with the Tanis recommended head "dog ear" mount location. The sport also has the exhaust O2 sensor cable mount on the water outlet pipe bolt so that Tanis recommended location could not be easily used either. I was able to remove the temp sensor, thread the bolt heater all the way into the ear, then put the aluminum spacers with a stop nut on the part of the bolt that stuck out the bottom of the ear (to conduct the heat from the bolt into the ear). After this was installed, I was able to put the water temp sensor back in and using a 3/8" drive breaker bar and a 19mm crowfoot wrench to tighten it (the heater bolt blocks a socket or box wrench from fitting on the temp sensor). I didn't want to put the heater bolt in the secondary location that Tanis recommends (I would have had to relocate the 02 sensor wire mount) because the head heater bolts were non galvanized or plated steel and were already starting to rust. I didn't want to take the chance of it reacting with the aluminum and I might not be able to remove them later if need be. I have had plenty of problems in the past removing steel bolts from aluminum blocks so I put anti-seize compound on the 4 steel heater head bolts to be sure. I also had a problem with one of the bolts threads on one of the head bolts was not quite right and I could not thread it in by hand and it started galling when it took it out, so I ran a die over the thread and it went fine for the first 10mm but then started to cut the threads away. I will have to see if Tanis will warranty that bolt.
