Normal water pressure for 250 HPDI ?

[Life in The Bass Lane]

I was curious to see what you guys are seeing for water pressure at average and wide open throttle on a 250 HPDI. I am still trying to find the " sweet spot " on the trim for my Z 21 250 HPDI. Thanks for the input guys !!

[PushNit]

Mine runs any where from 10 to 20+ depending on water temp. Alarms aint never went off yet.

[Life in The Bass Lane]

So the water temp has an effect on the water pressure... don't mean to sound dumb but after all these years I didn't know that.

[Glenn]

When I had my 521VX with the 250 HPDI at WOT my water pressure would be between 20 to 25 lbs. Now saying that in the summer months the water pressure would drop dramatically to less than 10 lbs and than jump up to around 16 lbs. Yamaha recommends a minimum of 11 lbs of pressure at WOT.
Good Luck with your motor - Glenn

[Life in The Bass Lane]

When I get the boat on plane she has plenty of pressure its just when I want to get some speed and trim up the water pressure drops and it confuses the hell out of me why. Some people said I many have trimmed up too high too soon but it can't be when I didn't even trim half way, not even a quarter....I'M CONFUSED AND CONCERNED. The rig is the best I ever had and love it to death and want to make sure she runs right. HELP !! I have a manual jackplate.

[21XDC]

I don't think the sweet spot will be found using water pressure on a HPDI LU with low water pick ups. You'll need to use speed, rpms and bow lift as a guide.

[Rebel1]

Like Glenn said, I have seen the exact same thing with mine.

[bassinengineer]

I heard the same from Yamaha as Glenn. If you have at least 11 PSI at all times, run it and don't worry!

There have been a multitude of posts on here about this subject, so research back if you want more detail (and get confused even more).
Mark

[21XDC]

I run even with the pad and as high as 1/2 above and never got down to 11 lbs water pressure. I have the HPDI LU. I doubt you'll run it as high as me.

[PushNit]

But your running 80+ that will push more water in there

[Slippy]

I have the 200 and mine seems to run about 15-23

[21XDC]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PushNit &raquo;</TD></TR><TR><TD CLASS="quote">But your running 80+ that will push more water in there </TD></TR></TABLE>





But at 60 I still have tons of water pressure.

[Bass Commander]

196 mile trip...I thought I made long runs!

[EJP]

"Mike, you know you are supposed to turn the GPS off while going down the road... You know darn well no yamaha will go that fast". quote from the most expereinced, only owned two boats in his entire life, Danco....... Just messing with ya bud!!

[Bass Commander]

EJP, thats funny. Some folks on the BFHP think of Danco as the bass boat authority. Some of us know better...

[Luke]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 21XDC &raquo;</TD></TR><TR><TD CLASS="quote">I don't think the sweet spot will be found using water pressure on a HPDI LU with low water pick ups. You'll need to use speed, rpms and bow lift as a guide. </TD></TR></TABLE>

i agree you will loose lift or speed way before you will loose H2O press with the LU that the HPDi has

[spider1]

Mike I guess that that speed is not to bad for a bullet! <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 21XDC &raquo;</TD></TR><TR><TD CLASS="quote">





</TD></TR></TABLE>

[PF22]

One thing to consider is that your poppet valve is open at higher RPM's allowing more water in and out of the motor. The flow can be as much as double with it open so while you may have &gt;20 PSI you are still pushing a good amount of water. Think of it this way, your water pump does 20+ PSI before you poppet opens up, now the water pump has an additional opening to push the water out of so it could result in lower water pressure. At least that's how it was explained to me but am no mechanic.

[BuzzB8]

You just HAD to say that five letter name!

[EJP]

DANCO DANCO DANCO.... hahahahahha BuzzB8 Im sent....