Intake Cooling Line Valves - Good or Bad?

[Jgorm]

You still need to use fittings though, and any decrease in diameter is affecting the flow disproportionately. I've learned that designing a ballast system.

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If you're super concerned about reducing it 1/16", then upsize the fitting, heat the tube with a lighter/ heat gun, soap it, and cram it on. As mentioned, all the other fittings have barbs that slightly reduce the id. It might be the difference of 50rpm worth of pressure.

 

[Neutron]

Everywhere the inlet hose connects to an existing fitting it has some sort of inside fitting that reduces the id so what is the issue with using a inside barbed valve.
Am i missing something here?

 

[Gym]

Oh - that totally makes sense!
I did not think of it that way, but now I wonder if one should always close the intakes (w/valves or grips) when flushing the engines. Also on land (on a trailer) - just to force more flow through the engine/exhaust passages.
I guess one would need to double check the valve closes the intake hose before the flushing line connects to it!

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Being a fresh water boater in MO., @swatski, you wouldn't have the same need as us salty dawgs but, as you stated, closing the valves does force the water up through the motor better as evidenced by a stronger flow from the pissers. To prevent forgetting to open the valves after flushing I leave a piece of red gimp hanging about two feet out of the clean out locker (I installed my valves under the clean out tray accessable by the access ports). If you install your valves in the engine compartment you could easily leave a red indicator hanging out of the engine hatch.

 

[Jgorm]

It won't work for flushing, buy i hook the keys to the valve to be 100% sure I don't forget to turn it back on.

 

[mrtoastyjr]

I'll be installing valves on mine. A ball valve will not have substantial restriction. I bought these for the wave runner. Performance Tool W83205 3-Piece Line Clamp Set https://www.amazon.com/dp/B003WZX7UA/ref=cm_sw_r_cp_apa_-x8WzbFS926SH

Be careful with these, I have a similar product at work and have had them leak on me (literally, on my head) when I’ve used the wrong size when pinching off radiator hoses and heater core hoses. The problem is they have a small space between the jaws to keep from pinching the hose too much, but some times that space ends up being too much and they don’t seal completely.

I found what works better is a pair of needle nose vise grips with a couple pieces of rubber tubing covering the jaws. You can adjust it to the exact tension you want without worrying about leaks.

 

[ISLANDRACING]

Probably 1000 kits by now sold over the years and still a "hot" item. NEVER any issues re cooling. ... Beside the hose may be 5/8" but the hole through the pump wear ring and transom plate is only about 3/8"

 

[Zonie]

These hose pinchers came recommended on the topic on Facebook:

https://www.amazon.com/gp/aw/d/B0002NYB78/ref=mp_s_a_1_1?ie=UTF8&qid=1505968229&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=hose+pinchers&dpPl=1&dpID=31ku8xwGFtL&ref=plSrch .

Seemed like a simple alternative... inexpensive, easy to use, and easy to carry.
View attachment 64375

Oh I like those! Just ordered a pair. I bought a set of these last year and put the two smaller ones on the boat but the plastic is a little flimsy and makes me nervous. https://www.amazon.com/dp/B01N1OGT2X?psc=1#customerReviews
They would probably work fine in a pinch if I ever had to get towed (pun intended)but aren't strong enough to clamp off a garden hose.