525 water pressure problem
06-09-2015, 10:15 PM
#11
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Im hitting the ole Mississippi tomorrow night, before I go I'm gonna flush things again, check that pressure sensor and just pray my hoses don't blow off. This is a weird problem, if all goes ok Ill make it home tomorrow night and post if anything changed.
06-18-2015, 03:31 PM
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Well I placed a mech gauge( 100lbs) on the imput to the front(engine) heat exchanger and another on both the port and star inlet to the headers. At 3500rpm the heat exchanger gauge shows 35lbs the inlet header gauges show 17lbs each. Called CMI (Dave) again and discussed my situation. Dave is really a nice guy. He want my boat fixed as much as I do. CMI is willing to flow/pressure test my headers. I live about 3 hrs from their location in Wis. It would be a one day ordeal. Called Mercury racing again. Nothing new on that end. Chris the main guy is out on a medical leave. Won't be back til end of July. I'm not sure where to look now. Having 35lbs at the heat exchanger wants to tell me the headers. flushed the headers removing the two tail(Rail) input lines and plugs being the blue drain plug and the 9/16 end allen cap. Back flushed from the restrictors. Found nothing. ............... crazy crazy crazy I'm surprised with over 500 hits on this offshore only site and nobody has had this problem/answer...Like I've said prior it's only a 525 Mercury Blue Motor I'll figure it out. The bad thing is the Wife isn't very happy. I'll keep this post open River Rat
06-18-2015, 07:11 PM
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Well things are not getting better, Replaced the water pressure sender(135.00) replaced the water pressure gauge(100.00) in the dash blew out the line. Took the boat out today at 4500rpm's blew off the hose at the inlet of the front heat exchanger. Nobody seems to know what is causing the high pressure nor do they care. It's a strange problem but I'll figure it out. Mercury racing tech's are zero help. Didn't even know how the oil cooler was built. Advised me to contact a local mercury service tech. Note: livorsi water pressure gauge was redesigned 4 years ago from a spring system to a gear drive gauge Also, the water pressure sensor that I replaced only tells the computer if you have LOW water pressure which will give an alarm. While under the dash installing the new water pressure gauge I decided to change the light blubs to LED blubs. Well the small gauges will accept the new LED blubs. The monster speedo and the tach will not accept the livorsi LED blubs. The new LED blubs are too thick expanding the socket making it too large to reinstall the socket into the gauge. Anyway now the GPS speedo is stuck at 30 mph More problems. I'll keep this post open until I fix my high water pressure problem and I will figure it out it's only a boat engine with 94hrs
06-18-2015, 10:30 PM
#15
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^^^^^^^^ Dave I know you bought the OEM Mercruiser HP 525 service manuals currently can you verify for me and whomever the water pressure specs and were it is taken. Please read post # 5 in this thread and see if I am correct as to what I posted. Thank you.. I sold my hp 525 service manuals a year or 2 ago.. Thanks again
06-19-2015, 04:00 AM
#16
Have a friend with a couple 525 efi's that consistently run over 40 # 's of pressure .No issues .The cmi headers have restrictors between header and tails that according to cmi help prevent hot spots in header
06-21-2015, 07:38 PM
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^^^^^^^^ Dave I know you bought the OEM Mercruiser HP 525 service manuals currently can you verify for me and whomever the water pressure specs and were it is taken. Please read post # 5 in this thread and see if I am correct as to what I posted. Thank you.. I sold my hp 525 service manuals a year or 2 ago.. Thanks again
06-24-2015, 03:54 PM
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I've been in contact with CMI regarding my high water pressure problem. The folks at CMI have been very helpful and are willing to do what ever to correct my problem. Yesterday I removed the restrictors and ran the boat WOT. I have about 45-47LBS pressure. Better water pressure without the restrictors. Still too high. My goal is 30-35LBS at WOT (Which is still HIGH). I'm going to run the boat for the summer as is. This fall the CMI headers are coming off and taken to the CMI factory for a flow test and a leak test. I'll keep this thread open until we test the headers this fall. Thank You all for the comments/concern. Problem still not fixed
06-25-2015, 07:26 PM
#20
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a friend of mine had this problem last summer, he finally removed both the engine cooler,, and oil cooler and used small wire to rod both, he got a 1/2 cup full of sand and some very small rubber impeller pieces out, he had back flushed a dozen times but flushing would not remove the pieces stuck in the tubes, they were stuck so tight he had to work to get them out but it fixed his problem immediately , good luck
