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737jetmech
04-23-2002, 08:52 PM
I have a 2.5 offshore with low indicated water pressure but engine temp never is higher than 140 degrees. Gauge shows only 8 or 9 psi at full throttle. Engine is a 1995 and impeller was replaced last season. I have only owned the boat for 1 year and water pressure remains the same from the day that we tested boat prior to purchasing. Water always flows out of the right tube after starting and after warm will flow from left tube. From what I've read on these forums 15 psi is required for the powerhead to live. With normal temps indicated should I be concerned about this??? Thanks Bob

HavasuDreamin'
04-24-2002, 05:49 AM
Yes, you should be concerned because the 140 degree temp is at the head, not the block. If you have a jack plate, lower it down until you reach minimum psi of 10-12 lbs (it won't take much, maybe 1/4 inch). If you don't have a jack plate, get one so that you can run your motor as high as possible while still maintaing 10-12 psi. I always run 12 psi or better unless I am racing someone, then I will allow it to dip down to 10 psi. Never less! I fried a motor by not paying attention $$$.

snappertapper
04-24-2002, 06:44 AM
i have fried three motors because of low water pressure if you have low water intake maybe it has something in it

737jetmech
04-24-2002, 10:30 AM
Yes , The motor is on a adjustable jack plate and the X- dimension is set almost as high as the hull running surface. I will try lowering a little bit and see if it helps. thanks Bob

snappertapper
04-24-2002, 11:29 AM
do you have low water intake if not then try clogging the top intake holes on your lower unit they may be catching air

737jetmech
04-24-2002, 01:56 PM
Yes I have low water pick-up on the nose of the gearcase. Bob

snappertapper
04-24-2002, 04:06 PM
ok ummmmmmm i dont know what could cuase the low pressure except the motor being too high

737jetmech
04-28-2002, 05:58 PM
Well after calling Liberator boats they told me that the X-dimension is ok and could go even higher.Dropped lower unit and removed pump assy. Found intake side gasket blown out.I am planning on replacing pump assy.That is the only thing that was found. Going to look for pump tomorrow morning. I also lowered motor a little bit . Hope that is the problem. Bob

737jetmech
05-06-2002, 07:24 PM
16 P.S.I. on test !!! Raised X-dimension back to original setting . Still have 16 - 17 psi. Bob

HavasuDreamin'
05-07-2002, 06:01 AM
There you go. I would raise the motor until I was at about 13 - 15 PSI or until speed started to fall off, which ever came first. Good Luck.

HavasuBarney
05-09-2002, 07:40 AM
737, you run a Liberator?

HavasuDreamin'
05-09-2002, 07:44 AM
Yes Barney, he has a 21' with a Merc 2.5 EFI, and NOS! It is in the readers rides I believe. http://free.***boat.net/ubb/smile.gif

737jetmech
05-10-2002, 05:49 PM
Originally posted by HavasuBarney:
737, you run a Liberator?
Yes Barney, I run a 21 tunnel w/2.5 offshore and Nitrox Nos system is on board for a little extra Hp when needed. Bob