650 thunderbolt water pressure

[Hookem Dano]

Would like to put a water pressure guage on my 1969- 650 65hp 4cyl. Can anyone tell me if I would just put a tee into the tell tale, or is there a plug on the motor somewhere I can use. Thanks guys for any Info. And I would just like to Add, I just started Boating last year at 50 years old. I had a bad Heart attack, and was told to take Life easy from here on in. So you guessed it! Bought the Wife a BOAT. I would like to thank all who helped me with the newbie questions, that old boat and motor ran perfect last summer and gave me one of the best times of my life!....... Thanks all

 

[Clams Canino]

Re: 650 thunderbolt water pressure

In a perfect world - no.<br /><br />There outta be a plug on the exhaust plate side OR the spark plug side, put a fitting in place of the plug.<br /><br />-W

 

[kozman01]

Re: 650 thunderbolt water pressure

I have a 69' Merc 800 and it's in between the #2 and #3 spark plugs on my engine. Should be the same on yours I think.

 

[Hookem Dano]

Re: 650 thunderbolt water pressure

Thanks Clams and Koz.

 

[andrewkafp]

Re: 650 thunderbolt water pressure

My 81 Merc has an outlet between 2 and 3 also and the pressure usually doesn't start registering until around 1500 - 2000 rpm and peaks at around 6-7 psi at 5000-5500 rpm. I would imagine that any change you notice would hopefully warn you of an impending pump failure or blockage prior to engine destruction. I have a 6hp Auxiliary for this event, but hope my preventative maintainence will eliminate it. I have found that boats are really not that good for relaxation, when you see some of the costs of parts and repairs and sudden bay conditions that send everyone russhing back to shore with panic striken looks of their faces But they do keep you sharp and on your toes.

 

[kozman01]

Re: 650 thunderbolt water pressure

What size it your 81' Merc. At those rpms, mine, if I remember correctly shows around 12-15 psi. Does this sound right to anyone. At idle, it's around 2 psi.

 

[andrewkafp]

Re: 650 thunderbolt water pressure

Mine is only a little feller 50HP. The big ones run at about 15-16 and at idle 2 psi sounds OK..<br />According to the Clymer manual.<br />My impeller is 47-89983 and your 800 would be 47-30221 (Bigger).

 

[Clams Canino]

Re: 650 thunderbolt water pressure

On the '73 150 I'm working on, it's between #3 and #4, ie the middle.<br /><br />-W

 

[Hookem Dano]

Re: 650 thunderbolt water pressure

Thanks again, for all the replys.

 

[RICKRICK1]

Re: 650 thunderbolt water pressure

Dano-- There is a plug on the top of the cylinder block. it is in the left rear corner. your upper cowling mount bracket should have an opening there. it is a 1/4 fitting. pressure at idle 2-3 psi, 5000rpm about 6-7 psi. Will register right after start up.

 

[Hookem Dano]

Re: 650 thunderbolt water pressure

Thanks RickRick, If I remember right you have a 650 think its a 67. Thanks again