View Full Version : How are small Chrysler 4 HP engines cooled

12-06-2007, 03:16 PM
just wondered if someone could tell me how the cooling system works in a 2 stroke outboard?


12-07-2007, 12:39 AM
"In a water-cooled engine, cooling is provided by a (water pump).

In the lower unit there is an "impeller" either around the drive shaft or the prop shaft that forces water out of it's housing up a water tube to the water jacket and channels surrounding the cylinders.

The water exits down the exhaust housing, thus providing two addition functions after it has cooled the power head - it also cools the exhaust to some extent and acts as a muffler to keep some of the noise down...."

03-24-2008, 01:55 PM
I have a 9.9 sea king and was wondering if the engine needs to be in gear in order for the impeller to circulate water?

03-23-2009, 09:34 PM
"I believe some of the older Chrysler one-lungers had air-cooled cylinders. If so, the water pump only cools the exhaust leg, and the cylinder block will have fins on it and the flywheel will have fan fins."