1968 evinrude 40hp lark water pump trouble

[redsmufc]

hi
i have a 1968 40hp evinrude lark, i have replaced the lower unit seals and impeller put it back together lower unit is fine but i have no water being pumped around any clues as to why??? the impeller is turning freely clockwise. i am baffled could it be water pump housing, and seals or both.

many thanks

 

[freddyray21]

Re: 1968 evinrude 40hp lark water pump trouble

are you sure the pick up tube got into the pump housing?

 

[redsmufc]

Re: 1968 evinrude 40hp lark water pump trouble

hi yeah it is located but the rubber grommet is damaged i have used silicone instead i did check it for leak and is was ok, also the seal inside the top of the water pump was seeping slightly would that cause a problem??

 

[redsmufc]

Re: 1968 evinrude 40hp lark water pump trouble

sorry to add to last post the pick up tube grommet is damaged in the lower end not in the water pump housing.

 

[freddyray21]

Re: 1968 evinrude 40hp lark water pump trouble

make sure the motor is deep enough in the tank or barrel. Some like to be deeper than others. Was is pumping water before you changed it?

 

[tashasdaddy]

Re: 1968 evinrude 40hp lark water pump trouble

be sure the key didn't slip out.

 

[F_R]

Re: 1968 evinrude 40hp lark water pump trouble

If that inlet tube is not sealed, it will suck exhaust gasses instead of water.

 

[Evinrude Boater]

Re: 1968 evinrude 40hp lark water pump trouble

Confirm the blades on the pump impeller are curve the correct way, backwards to rotation.

 

[K.B]

Re: 1968 evinrude 40hp lark water pump trouble

Good evening to you!

I have a '71 40 hp evinrude that I had problems w/ when I acquired it. Not knowing your engine history, also check your compression. Blown head gasket was my culprit for no water.

 

[F_R]

Re: 1968 evinrude 40hp lark water pump trouble

Is the thermostat and relief valve in the head? People love to throw those parts away and then wonder why it won't pump. Especially the relief valve, it has to be in there.

 

[redsmufc]

Re: 1968 evinrude 40hp lark water pump trouble

hi yes it was pumping before, and the impeller is in the right way round. i filled the tank untill the water was about level with the water pump. so would the inlet tube be top suspect? would the shaft seal in the top of the water pump housing cause any major problems?

 

[F_R]

Re: 1968 evinrude 40hp lark water pump trouble

The shaft seal in the housing will allow air in and water out if it is real bad. Related to that is a small hole in the pump outlet tube adapter that keeps that area filled with water. Anything that lets air into the cooling system is suspect and most have already been mentioned.

Water tube
pressure relief valve missing or blocked open by trash
blown gasket (s)
bad/worn pump housing
bad housing sealing, above and below

 

[redsmufc]

Re: 1968 evinrude 40hp lark water pump trouble

thank you very much for your help i'll check it out during the week and test it again