It's the compression changing screw. It needs a locking nut to keep it from backing off and lowering the compression. These engines run on ether/Kerosene/Castor oil mix, and compression only, with no glow plug. It's adjustable for different mixes of the fuel and how warm the engine/weather is. Diesels never caught on here in the 'States. They are more quiet than 2 cycle glow engines. Similar to a 4cycle. They do slobber a bunch of unburnt fuel out, mostly on your airplane, and some folks hate that.
What's the t shaped thing on the top?
It's the compression changing screw. It needs a locking nut to keep it from backing off and lowering the compression. These engines run on ether/Kerosene/Castor oil mix, and compression only, with no glow plug. It's adjustable for different mixes of the fuel and how warm the engine/weather is. Diesels never caught on here in the 'States. They are more quiet than 2 cycle glow engines. Similar to a 4cycle. They do slobber a bunch of unburnt fuel out, mostly on your airplane, and some folks hate that.
Bellissimo ma bisogna serrare le 3 viti che fissano la testa !