Plumbing Question?

[75 Eliminator]

Hi, I just bought a jet boat and the plumbing on it is not right, my dad used to have a jet boat but that was back in the 80's and he can't remember how his was. I was wondering if someone could give me a detailed explanation on the best way to go about this. I know some things but, I just want to make sure I have no problems. I do have water injected Bassett headers. Also does anyone have a dual carb air scoop their willing to part ways with?
Thanks, 75 Eliminator, New to the Forum!

[67weimann]

Do a search. this topic has been covered over and over...:D
Here you go...
http://i29.photobucket.com/albums/c283/Roll_me_over/diagramjet.gif
The black T is the Bassett T-valve or equiv....The two red hash marks are gate valves...

[wickedfab]

i have a basset t valve if you need one

[thatguy]

Mine is a little diffrent. But that is an excellent diagram. The main line comes off the jet. It feeds everything. I would hard line it w/ 1/2" pipe with a gate valve on it close to the jet. Just make sure you put the valve BEFORE anything else! That valve could save your boat if a line blows. Remember, it's just like pulling the plug if you lose a line. Then T the line. One will feed the engine, one will feed the headers. Each should have a means of adjustment. The header line can easily be T'd with the Bassett spring loaded T as above. Cheap and effective. I have a manually selected valve on mine by the driver. I shut it off befor killing motor so no water can enter heads. DO NOT run it to the headers without one or the other as it will fill a chamber with water and could destroy your engine.
The engine line should have a gate valve for adjustment, then T and feed into the where the water pump normally goes. When running, the gate valve is adjusted for engine temperature. The thermostat housing shoud have a heater hose outlet on it. That goes to the transom outlet and the water flows out the back of the boat. I do not ever run a valve on the outlet like the gentlman above, although many, if not most, people do. The reason I don't is because if it is too restricted, the jet pump will push water into the engine internals, past gaskets. If you run just one exit hose, it is naturally restricted due to having 2 inlet feeds at the water pump.
All of these parts can be seen at www.cpperformance.com I am not promoting their site, just a quick way to view them.
You will probably see a flury of disagreements on this, but remember. This is the basics. 10 jet boats will have 10 slightly different set ups. Just watch the Temp. gauge very closely at first. Let it idle in the lake and warm up with the valve to the engine wide open. Probably get no warmer than 150 or so. IN SMALL INCREMENTS start restricting the inlet to the engine until it stays around 180. Then wire tie the valve. Presto, go boating! BE SURE to double check the Temp. when running hard and make final adjustments. You may have to open or close it a little. Leave it adjusted for hard running.
Here comes the debate!

[67weimann]

The diagram I posted above is from Bassett's website and the way "they" recommend it be plumbed. I know lots of guys that don't run the valve on the dump line. They only run a valve on the inlet...:D

[75 Eliminator]

Thanks, for the help, I'm sure i will have other questions.
75 eliminator:D

[Some Kind Of Monster]

The diagram I posted above is from Bassett's website and the way "they" recommend it be plumbed. I know lots of guys that don't run the valve on the dump line. They only run a valve on the inlet...:D
I have a dump line valve, but it doesn't matter because my motor likes it wide open. Some DO need the dump line valve in order to build pressure to open the Bassett valve.

[dumbandyoung]

http://classicboatbeachbash.com/05page/otcoolingdiagram.jpg
This Diagram shows the Drag-n cooling system for Bassett injected headers with the T-Rex cooling tower. I have four valves to control flow...dump lines are sized to keep engine coolant pressure low. The key is using #8 braided SS lines for engine inlet and dual dump lines. Then by splitting the inlet to the engine with a T-connector, pressure from the pump is reduced further to safe levels (even when the 1/2 inch ball valve is full open.) The 1/2 inch ball valve on the pump hard line is a safety shut-off. The 3/8 inch ball controls the rpm for header injection; note this valve is on the engine inlet line and not the header line. The 1/4 inch balls adjust total flow and balance to headers...lines to the headers are smaller #6 braided stainless steel.
I've found the 1/2 main ball valve only needs to be open about half-way to supply flow for safe idle temp even on a hot day (air temperature 115 F, water temperature 80 F)...still keeping the chrome on. I'd recommend a minimum bleed from the pump that fogs the headers above 1500 rpm and maintains a maximum engine idle temperature of 180 F on a hot day. This requires balancing the main valve flow against the header valves, but once set can be left alone. The thermostat takes care of adjusting for cooler lake days.
Measured pressure data: With the 1/2 ball full open, the pressure at the tower is less than 30 psi at full throttle. However, with this setting, full throttle and idle engine temperatures are below ideal operating temperature. With the 1/2 ball set to give more acceptable idle temps near 180 (hot day)...full throttle pressures are less than 5 psi. This gives excellent protection from blown head gaskets and water in the oil. Note large twin dump lines and NO valves on the dump lines...important considerations for a reliable coolant system. No pressure regulation is needed.
Submitted by LVjetboy
http://classicboatbeachbash.com/05page/logscoolingdiagram.jpg