1999 Air Nautique GT40 DIY Engine Flush/Test Connection

[Joshua J Rowe]

This is my home made engine flush/test connection. With this I can connect a hose directly to the engine and draw water from a spigot or a bucket to run the engine in the driveway. It can also be used to fill the engine with antifreeze in the fall. I do not suggest running the boat from a spigot. The cooling system is not designed for high pressure. The typical automotive cooling system pressure relief valve is 14-18psi, my water pressure is 88 psi. I have a 5 gallon bucket I am going to fit a bulkhead and hose bibb on which is where I will connect to. The hose from the spigot goes into the bucket to keep it full.

After looking up what was available all I found was a plastic check valve, which looked cheap and unreliable. My solution did not save me any money over the $90 check valve available online, but it is never going to break or wear out.

Piping is 1" for this boat. I got all of these parts in the plumbing section of Lowes, cost about $85. Could have been done for a fraction of that price if all plastic was used, but I was going for maximum reliability and durability. If you use plastic I suggest you use CPVC not PVC, CPVC tolerates a higher heat range. Joints were sealed with plumbers tape, no special tools required.

[DLafont]

Nice setup. Any chance you can spare me the trouble of un-doing my strainer and do up a parts list?

[Joshua J Rowe]

Nice setup. Any chance you can spare me the trouble of un-doing my strainer and do up a parts list?

Sure thing. I am at work right now, will list the parts this evening when I get home.

[Quinner]

Looks good Joshua, nice work!

As an alternative here is a link to another similar homemade device commonly referred to as the Timmy T, will also be a few $$ cheaper:
http://www.correctcraftfan.com/forum...-i-doing-wrong
If you intend to use the hose for sucking up antifreeze then you will want a 2nd shut off on the tee towards the hull intake like Joshua used.
Would not be afraid of using the plastic (PVC) pieces since there are other PVC pieces in the system already, like the strainer and it's elbows.
Ideally I would prefer the strainer cup facing down so when you remove it the contents do not pour out into the bilge.

[Joshua J Rowe]

Looks good Joshua, nice work!

As an alternative here is a link to another similar homemade device commonly referred to as the Timmy T, will also be a few $$ cheaper:
http://www.correctcraftfan.com/forum...-i-doing-wrong
If you intend to use the hose for sucking up antifreeze then you will want a 2nd shut off on the tee towards the hull intake like Joshua used.
Would not be afraid of using the plastic (PVC) pieces since there are other PVC pieces in the system already, like the strainer and it's elbows.
Ideally I would prefer the strainer cup facing down so when you remove it the contents do not pour out into the bilge.

Thanks. I am happy with it

I agree with what you say about the strainer being inverted, still looking into where exactly I want it to go. I will follow up on that.

With respect to the plastic. The big thing here are the valves. Plastic valves have a poor service record and a much shorter service life(about 5 years). I may be a bit biased, as I am a plumbing Engineer and the other engineers, plumbers, maintenance technicians, and product representatives I have talked to tell me plastic valves are junk. I prefer reliability over cost savings so I didn't take the chance. This setup will last as long as the boat without any issues. I am not telling anyone not to use plastic, just passing along the information I have and why I decided to go this route.

Also, if you look closely you can see the strainer has melted in one spot! The previous owner had it smashed against the engine/exhaust manifold. I doubt very much the ambient temperature in the engine compartment gets hot enough to melt the plastic, but obviously contact with the engine can.

I am fond of overkill.

[Joshua J Rowe]

Nice setup. Any chance you can spare me the trouble of un-doing my strainer and do up a parts list?

As Requested.

1. (2@$7ea) 1” MIP Close Pipe Nipple - BrassCraft #112-16-RX P.
2. (1@$2) 1” MIP Close Pipe Nipple - Mueller Proline 10600
3. (1@$6) 1” MIP tee - Mueller Proline 60405
4. (1@$12) 1” FIP x 3/4” FIP Pipe Reducer Coupling - BrassCraft #119-16-12XCB P
5. (1@$8) 3/4” Quarter Turn Hose Bibb - American Valve #M71QT (Don’t buy these, gets terrible reviews. Going to return mine for an Apollo equivalent)
6. (1@$27) Apollo 1-in Brass Female In-Line Ball Valve - Apollo #LWS70LF105

Total of about $70

Could save money by using all galvanized fittings. I would have gone 100% brass but they did not carry a 1" brass Tee fitting so I used galvanized.

I also bought a second 3/4" hose bibb and a 3/4" bulkhead that I will fit onto a 5 gallon bucket. With that I will be able to fill the bucket with water or antifreeze and bring it into the boat, connect a short hose from the bucket to the valve on the boat and be able to flush the engine or winterize very easily.

[Joshua J Rowe]

F=female, M=male threads.

MIP fits into FIP. This is the threading of the strainer and the hose barb fittings connected to it.

[DLafont]

Thanks man!! You rock!!

[JD ski]

Joshua, as you mention water pressure from a hose can be a huge issue as head gaskets are designed to hold cylinder pressure in the cylinders. Usually water pressure can only be around 12-14 lbs. I found this out the hard way by blowing through two head gaskets while sitting in my driveway starting a new motor and running a Fake-A-Lake. I never thought about pressure from the water source causing a gasket problem. The Fake-A-Lake does not connect directly, lots of room for pressure relief, or so I thought.

I talked to a engine builder and he informed me about the pressure issue and why cars have radiator caps that are rated for a specific pressure. Then he informed me that for boats you can buy pressure regulators to attach to your hose to bring down the pressure to an acceptable point. These regulators are available at RV- trailer dealers. Some are adjustable and some have set pressures. The set pressure regulators are not very expensive and will keep you from blowing head gaskets. I purchased one for 10-12 lbs and have never had another problem with too much water pressure for the motor.

[Joshua J Rowe]

Joshua, as you mention water pressure from a hose can be a huge issue as head gaskets are designed to hold cylinder pressure in the cylinders. Usually water pressure can only be around 12-14 lbs. I found this out the hard way by blowing through two head gaskets while sitting in my driveway starting a new motor and running a Fake-A-Lake. I never thought about pressure from the water source causing a gasket problem. The Fake-A-Lake does not connect directly, lots of room for pressure relief, or so I thought.

I talked to a engine builder and he informed me about the pressure issue and why cars have radiator caps that are rated for a specific pressure. Then he informed me that for boats you can buy pressure regulators to attach to your hose to bring down the pressure to an acceptable point. These regulators are available at RV- trailer dealers. Some are adjustable and some have set pressures. The set pressure regulators are not very expensive and will keep you from blowing head gaskets. I purchased one for 10-12 lbs and have never had another problem with too much water pressure for the motor.

Sorry to hear!

I figure drawing out of a bucket protects from pressure, and is a way to test that the impeller works well enough to draw water.

For anyone who does not know, the boiling point of water increases as the pressure on the water is increased. For this reason closed loop cooling systems are allowed to build pressure, up to a certain point, to raise the boiling point enough so that it does not boil as it passes through the engine. The pressure relief valve is set to hold enough pressure to give the water a high enough boiling point for proper operation.

The reason a radiator can explode in your face if you take the radiator cap off when it is hot is because all the water in the entire system will boil immediately if the temperature is above the boiling point at atmospheric pressure. For instance, if your coolant is 240 degrees F( which would require an additional 10 psi above atmosphere at sea level to stay liquid) and you take the cap off, the pressure drops to atmospheric and the water instantly boils. I have met 1 person who has made this mistake. His entire hand and half way up his forearm was a different color from the burn.

[JD ski]

Sorry to hear!

I figure drawing out of a bucket protects from pressure, and is a way to test that the impeller works well enough to draw water.

For anyone who does not know, the boiling point of water increases as the pressure on the water is increased. For this reason closed loop cooling systems are allowed to build pressure, up to a certain point, to raise the boiling point enough so that it does not boil as it passes through the engine. The pressure relief valve is set to hold enough pressure to give the water a high enough boiling point for proper operation.

The reason a radiator can explode in your face if you take the radiator cap off when it is hot is because all the water in the entire system will boil immediately if the temperature is above the boiling point at atmospheric pressure. For instance, if your coolant is 240 degrees F( which would require an additional 10 psi above atmosphere at sea level to stay liquid) and you take the cap off, the pressure drops to atmospheric and the water instantly boils. I have met 1 person who has made this mistake. His entire hand and half way up his forearm was a different color from the burn.

Great description,
I was aware of the pressure for boiling but never thought about too much of that pressure blowing a head gasket from a water jacket into a cylinder. I always thought of it occurring from a cylinder (higher pressure to lower pressure) a water jacket. I was informed GM small blocks were fairly susceptible to this in the back cylinders and GM big blocks were highly susceptible almost always on the left side. My Nautique has a Timmy T, my Century uses a Fake-A-Lake.
Nice work on the fresh water system.

[Joshua J Rowe]

Video of this thing in action at the link below.

https://www.youtube.com/watch?v=scWKHwovLs8