Raw water pump?

[Ron]

I am still (inventing) a way to convert my 5411 to a fresh water cooling system. I can use the impeller pump on the engine to circulate the fresh water side.What are your thoughts on pumps to pump the raw water through the heat exchanger? I was thinking of going with an electric pump rather than trying to mount another impeller pump on the engine. The plumbing would be easier. And it can be wired to turn on only when power is to the engine for starting. I believe the exhaust system can expell a constant flow of water when the pump is pumping but the engine is not running. Thoughts on GPH or pressure or size of pump?Anyone tried this? Comments? Ideas? Crazy?

 

[Jim Logan]

Electric raw water pump

I've actually used this system on a generator system to replace a freshwater pump that was impossible to get to without pulling the generator. Actually, it worked well, but there are two very important points.1. the engine must be running before the pump starts, else you will flood the engine with water through the exhaust system (if you have the standard exhaust elbow water injection type system), and when you try to start it, it will destroy the engine. A timing circuit or other short (1-5 second) delay should be built in to your control circuit.2. You must have a way to shut down the engine if the electric pump fails. If the overheat circuit will work this way, then that may be enough for you.You need to use a high quality pump and be prepared for the installation to not be as durable as a belt driven unit, but it will work and work well, if the pump is sized to provide the correct (not to much or to little) flow for the system, else you could cause some problems.

 

[Todd Osborne]

One thing to avoid...

is having the pump pump water into your exhaust system when the engine is not running. your aqualift muffler will fill and the next available space is your engine (yikes!). Without the exhaust to lift the water out the muffler you are in danger of ruining your engine by filling it with water. Also the increased backpressure from the muffler being filled with water will require much more power to turn the engine over. Add in the draw from the sepreate electric water pump & you might not even be able to start the engine (as it fills with water while you try).Bottom line, activate the raw water pump only after the engine is running.

 

[Hayden Watson]

easy way

There is an easy way to control the electric water pump. Use a relay that is hooked up to your oil pressure light. When there is no oil pressure the light is on and the pump doesn't run. When the engine starts, the light goes out and the pump starts. Most cars with electric fuel pumps use this system to shut the fuel pump off in event of an accident.Hayden WatsonS/V Papillon1988 C30 tr/bsSpokane, WA