74 johnson 70hp water outlet

Greetings! Just signed up. I've recently acquired a boat with a 1974 70hp johnson. I lowered the engine into a drum of water to make sure the water pump worked and the only water exiting I could see was on the front of the lower unit just below the pivot for the motor. There seems to be three small holes there that the water was exiting through. Is this correct or should it be also coming through the two outlet holes below the motor cover on the back side? Thanks for any help!

Re: 74 johnson 70hp water outlet

How low is it in the drum ??

Re: 74 johnson 70hp water outlet

boobie said:

How low is it in the drum ??

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The water is over the cavitation plate

Re: 74 johnson 70hp water outlet

mark k. said:

The water is over the cavitation plate

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Also from other posts I've read it seems that the water is expelled underwater on this motor, there may be some mist or spray from the top two holes beneath the engine cowling.

Re: 74 johnson 70hp water outlet

The engine needs to be lowered until the water level is well above the pump in the lower unit.

Re: 74 johnson 70hp water outlet

Daviet said:

The engine needs to be lowered until the water level is well above the pump in the lower unit.

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well, I did have it about 6 inches above the cavitation plate almost what it would be at rest in the water. I would think that would be deep enough don't you?

Re: 74 johnson 70hp water outlet

Yep, that should be deep enough.
How was the temp of the cylinder head, could you hold your hand on it for a count of 4 or 5?

Re: 74 johnson 70hp water outlet

Haven't tried that yet. Will probably try that tomorrow if its not thunderstorming. I'll have to put on the muffs.

Re: 74 johnson 70hp water outlet

Any other suggestions or things I should look for while I'm at it would be appreciated. Thanks Admiral.

Re: 74 johnson 70hp water outlet

for those that know how poppet valves work ,& know the amount of pressure it takes to compress a poppet valve spring on these motors , as there are 2 springs in this motor , next time you have the opportunity to hold one of these springs in your hand , put it between your 2 fingers & compress it , then you can work it out for your self how much water pressure is needed to open the poppet valves .

what i find the the slower the rpm at idle the water pressure gets released through the **** hole on the exhaust box & no or hardly any water coming out the 2 hole at the top of the leg below the cowl , as you increase the rpm the water pressure builds up , wait a few seconds , and then you see the water coming out clearly , providing the poppet valves & springs doing what its suppose to do , work & not stuck in the closed position as i have found in the past caused by salt corrosion .