How does the TD-20 Impeller pump water

[mrtapes]

Hi,
I have a question regarding the TD-20 water pump. I have done a lot of research on this and have a new impeller on the way from Brian Wilcox.
My question is this:
How does this impeller work?
It doesn't appear that it spins around on the eccentric. Does it just pulse?
Or what?
Thanks for any input.
Mark

 

[1946Zephyr]

Re: How does the TD-20 Impeller pump water

It's a tear drop oscillating type that mounts in behind the prop. Just remove the prop and then the little plate behind it. Since these motors are direct drive and the prop spins the whole time the motor runs, they just put it behind the prop.

 

[boobie]

Re: How does the TD-20 Impeller pump water

If I remember right it does spin around on the eccentric in an up and down motion. Correct me if I'm wrong.

 

[mrtapes]

Re: How does the TD-20 Impeller pump water

It doesn't seem that the impeller would spin, There really isn't enough room inside the housing. My thoughts were that the eccentric movement would make the impeller sort of pulse and pump. I'm just looking for some sort of verification of this fact.

 

[mrtapes]

Re: How does the TD-20 Impeller pump water

It's a tear drop oscillating type that mounts in behind the prop. Just remove the prop and then the little plate behind it. Since these motors are direct drive and the prop spins the whole time the motor runs, they just put it behind the prop.

I already know where it is as I have the whole thing dismantled and a new impeller on the way to install. I'm just looking for some sort of explanation as to the principle of how this pumps the water.View attachment 114871View attachment 114872

These images are from the Big Lures tutorial on the TD cooling system.
As you can see there isn't much room inside the housing for the impeller to spin as the impellers on say my 1971 and 1979 Johnson 6 and 15 HP motors do.

 

[Chinewalker]

Re: How does the TD-20 Impeller pump water

The impeller does not spin, it merely moves up and down with the eccentric on the propshaft. The nut at the top of the impeller acts as a plunger.

 

[1946Zephyr]

Re: How does the TD-20 Impeller pump water

I already know where it is as I have the whole thing dismantled and a new impeller on the way to install. I'm just looking for some sort of explanation as to the principle of how this pumps the water.View attachment 114871View attachment 114872

These images are from the Big Lures tutorial on the TD cooling system.
As you can see there isn't much room inside the housing for the impeller to spin as the impellers on say my 1971 and 1979 Johnson 6 and 15 HP motors do.

Well, the simplest way to explain it, is to slowly turn the flywheel in the direction the motor runs and you'll see exactly how the impeller operates. The metal cam that the impeller fits around oscillates the impeller to force the water up the water tube. The driver cam spins, but the impeller doesn't.

This type of water pump is also used on the HD model, some Gale models and even at least one Scott/McCulloch model.

 

[mrtapes]

Re: How does the TD-20 Impeller pump water

Thank you Chinewalker and 1946zephyr, you have both answered my question and confirmed what I had thought.
As there isn't enough room for the impeller to spin I figured it was a pulsing action, Just wasn't sure.
I appreciate the replies.