59 lark 35

stolty

Recruit
Joined
Aug 24, 2012
Messages
3
new pump impellor, seals, tube grommets and 'o' rings. ran engine about 2 min and waterflow stopped. dropped lower unit and pump looks ok. will no thermostat cause this? stolty
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 59 lark 35

If you don't have a thermostat in the system, it should not have any effect on the water flow. You might try attaching a hose the the water tube that goes up to the block and make sure the flow through the system is good. Sometimes a defective head gasket will allow compression into the cooling system and overpower the pump pressure causing the engine to overheat.
 

ronboonville

Petty Officer 1st Class
Joined
Jun 6, 2012
Messages
287
Re: 59 lark 35

check woodruff key at pump, also you might remove the pump inlet cover to get a better pickup if running in barrel.
 

stolty

Recruit
Joined
Aug 24, 2012
Messages
3
Re: 59 lark 35

If you don't have a thermostat in the system, it should not have any effect on the water flow. You might try attaching a hose the the water tube that goes up to the block and make sure the flow through the system is good. Sometimes a defective head gasket will allow compression into the cooling system and overpower the pump pressure causing the engine to overheat.

water flow good. will definately check head gaskets. stolty
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: 59 lark 35

Lack of a thermostat may not affect water flow, but lack of the plastic thermostat HOUSING and check valve certainly will. Those parts must be in there or the pump will suck exhaust down through the return water tube, effectivly admitting air into the pump inlet. They are good water pumps, but lousy air pumps.

So...are the housing and check valve parts in the head?
 

stolty

Recruit
Joined
Aug 24, 2012
Messages
3
Re: 59 lark 35

Lack of a thermostat may not affect water flow, but lack of the plastic thermostat HOUSING and check valve certainly will. Those parts must be in there or the pump will suck exhaust down through the return water tube, effectivly admitting air into the pump inlet. They are good water pumps, but lousy air pumps.

So...are the housing and check valve parts in the head?

Yes, to the hosing and check valve. good info. however I pulled the exaust cover and found a dime sized object acting as a check valve in the cover. thanks for the great input, it helped further my search. stolty
 
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