U.S.Corst Guard 44feet LifeBoat Model@-02-
Water-cooled machining
1.When the scale of sound is desired, they are 4 cycles too.

2.In order to carry out water-cooled machining, there were some conditions.
Water-cooled machining is difficult for 4 cycles on a head like 2 cycle on structure. Although there is also a hand of air cooling, water That is, it is necessary to cool a cylinder.

3.A jacket is required in order to cool a cylinder.
In order to attach the jacket, the round shape of a cylinder case is an ideal.

4.It lets the crevice between a case and a push rod pass for a jacket. A to some extent large crevice is required.

5.First stage type FA30 fulfilled these conditions.
The case of FA30 has not processed it.

Brown is o-ring-rubber with a 2mmphi diameter of 30mm.

Yellow is a silicone caulking.
Pink is a water-cooled jacket.

Jacket is No.767 of K&S co.(japanese company)
Muffler band phi40 TYPE-II The nipple is stood to this.

TSK-water cooled ring
(left photo.)
Water-cooled ring .It only inserts in an air-cooled engine.
Since the layer of air is in between, efficiency is very bad.
Although I also have, it used electric boat of another page. It uses for cooling a motor.