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1960 Lark ii 40hp cooling system help

ajamben

New member
Hello!

Last fall I traded a van for a 1959 Lonestar with a 1960 Lark ii 40hp. It had sat for maybe a few months according to the PO. I resealed the lower unit, new impeller and gear oil, rebuilt the carb and the fuel pump and new plugs. Set the points gap and we seem to be running good. The other day in a barrel is the first time I've had it running. I expected to see some water coming out somewhere. It seems like the water outlet for the cooling system on these is in the exhaust where the little rubber boot connects to the rear housing. I figured the thermostat hadn't opened yet. They are cheap enough I went ahead and ordered one, and figured I would just pull the existing one out and run without one to tune the carb and put in the new one later. I checked and there is not one there. I blew compressed air into the outlets inside the housing. The one farthest toward the starboard side seemed to run down to the water intake and I got air passing through. The other into the head it was harder to tell. It was bone dry in there, but this was two days after running in the barrel, so that might make sense.

My questions are,

-How is the water supposed to come out on these? Some videos online show steam kind of shooting out the exhaust, while my last (newer) outboard had a steady stream of water, so I'm not exactly sure what I am supposed to be looking for.

-I am 99% certain the key for the impeller is in place, and that it is oriented correctly. If my thinking is correct, I can verify the impeller doing it's job by checking for flow at the thermostat housing, correct? I can drop the lower unit if I need to, but I think this would verify if the impeller is moving water.
 
I poured water down all three of the holes in the thermostat housing and it came out the intake. I pulled the thermostat housing cover off and ran the motor. Initially it sprayed a little bit of water out, leftover from pouring it in I imagine, and then there was no flow.

Any ideas?
 
The thermostat and the parts below it MUST all be un place.-----Water must be 6" above impeller .-----Water pours out of that hose at full throttle.-----Slows to mist / spray at idle.
 
The water comes out of the exhaust port, the one where the rubber boot connects to the rear housing. If it does not start within a minute you have impeller issues. Water in a barrel should be above the vent on the port side of the lower housing. You do NOT need the thermostat. Unless you run in cold (under 50deg F). The purpose is to warm the water heated choke on that 1960 BigTwin. I find the manual choke works great. once it's running you don't want choke anyway. The engine runs clockwise looking from the top. the impeller blades should lean to the right looking at the bottom of the impeller housing
 
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