View Full Version : Water Pressure - Help

06-24-2016, 04:21 PM
So I took my new beast out for my maiden voyage today and promptly overheated... I think. Have a look here:


Notice the two vinyl/reinforced tubes coming up either side. That's my "water in" from the pump. There is a valve in the back at the pump, which I opened. When I was sitting and idling, I could watch water "bouncing" up and down in those intake lines, but never quite making it all the way up to the inlet. When I popped the throttle I could see the water column rise up, so I decided to try a test run. When I got on the throttle (Oh, my - it was orgasmic) the water sure seemed to start flowing... I could see heavy vapor coming out of the Headers and my water pressure gauge started registering and the engine temp was around 215-220. However, when I got back off the throttle, I don't think the water was flowing and the engine temp quickly climed back up towards 240. Is there some "balancing act" I have to perform with my water?
Any help appreciated.

HB Vic
06-25-2016, 06:07 PM
Oh man that's a bummer and definitely not good for idling. I'm pretty sure I've seen the jet guys screening around with a valve or valves because If I'm not mistaken you can have way too much pressure. But not enough is a mystery to me.

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07-20-2017, 04:50 AM
I'm not positive but I thought the water was suppose to run threw the block first then up threw the intake and out to the headers if I'm wrong I'm open to the correction or maybe I'm just viewing the pic the wrong way !

07-21-2017, 06:26 PM
If you look online you should be able to find enough images under "jet boat cooling diagram" to get a comfort level after comparing several pics...

Here is one that i found, looks like pressure valve TO logs for preheat TO block and then exit from the "water outlet (where your clear lines are attached):