Join Date: Feb 2001
Location: Northeast Wisconsin
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Water Heater By Pass Valve
A Catalina 38 owner sent in a picture of his by pass valve installation and
it is on the following web page:
He reports about 7.5 knots using a 16 inch, feathering Max-Prop
set for # 16 in the Max-Prop book. As of 24 Oct he was not
sure the valve was open or closed, but he never overheated.
A Catalina 36 owner posted the following well written summary on Oct 14, 02:
> Short story: With the water heater removed the engine will stay
> _exactly_ at the thermostat setting even at full throttle.
> Since I changed to a larger prop, my M25 engine became cooling
> limited. That is I had to reduce the RPMs or the engine would
> eventually (after about an hour) over heat. With the old 15x11
> fixed prop I did not have a cooling problem but with the 16x11
> folding prop I do.
> Easy fix. I opened the heater by-pass valve. I have a 160F
> thermostat installed and with the bypass valve open the engine
> will not heat about 160 even at 90% throttle for an hour.
> I was able to do a pretty conclusive test as I had to motor in
> dead calm at 8:00am to a race start.
> What this proves to me is that having a water heater plumbed in line
> with the engine coolant greatly reduces the engine''s cooling
> ability by slowing the coolant flow through the engine and the
> heat exchanger. With the bypass valve I can switch the water heater
> in and out of the loop in a second by turning a 3/4" ball valve
> handle and can see the effect quickly