Opposed Twin Water Circulation

[joecb]

Looks pretty … good job

Joe B

[Bob Wight]

The “before” pic had me fooled – good to see you got it worked out.   Going to be another good looking motor.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[labrador-guy]

Speaking of siphoning, in my younger days trying to siphon gas, you know suck suck spit kinda thing!  I could never get it going with both tanks the same height.  Only had luck when one tank was higher than the other.  On these old kickers both ends of the water inlet/outlet are the same height.  That seals the air bubble in the power head.  No water can flow until the air is moved out.  Do you guys think there should be a small hole in the down hill tube.   Once forward movement starts the water going up the tube the air can get out and the water goes over the hill and air pressure is relieved  shouldn’t it  work better.   Maybe even leave the down hill tube open for a pee’er?

wadayathink

dale

[Buccaneer]

I don’t think a pee hole in the water outlet is beneficial in this system.
The pee hole might just suck air in, lessening the siphoning effect.
The water coming into the powerhead should push air out of the whole
system.
According to my wife, I’m wrong at least once a day, so other opinions
may be better!

Prepare to be boarded!

[dave-bernard]

to me it is more like a push then pull system. scoop is being pushed by the movement of the motor forward and the exit is being pulled by prop thrust. not like a siphon.

• This reply was modified 2 years, 10 months ago by dave-bernard.

[Buccaneer]

Atmospheric pressure must come into play when siphoning effect is happening.
Is the pressure in “front” of the prop, where the water from the powerhead exits,
under less pressure than behind the prop?

 

Prepare to be boarded!

[Tubs]

The propeller as well as the forward motion of the boat pushes
water up the intake tube. This same forward motion creates
suction as the water passes where the water exits. Gravity
also helps the waters exit the motor. To get the water circulating
you should immediately go to full throttle. Then you can slow
down if you choose, checking the cylinders to be sure water is
circulating. For this system to work properly, especially at slow
speed, there cant be any air leaks. The motor above, I posted a
picture of, cooled well at every speed.
Tubs

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

[labrador-guy]

Buccaneer wrote:

Atmospheric pressure must come into play when siphoning effect is happening.
Is the pressure in “front” of the prop, where the water from the powerhead exits,
under less pressure than behind the prop?

 

Good question Buc!    It would sure be nice if a guy would know if the water system is working before it starts smoking.   Where there is smoke there is heat!   That is good for pancakes!

dale

get’em wet….don’t lit’em set!!

[joecb]

Defiantly more “push” than “pull” I think.  Also maybe a little help from the thermal action in the water jackets, hot water does tend to rise.

Joe B

[Author]

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