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Low water pressure
so I have been trying to track down why I have low pressure in one motor . I replaced both sea pumps. Then again on the low pressure side. I used my boat once the year before but never ran it up to temp. Was very busy. So this year I have gotten out on it 3 times and trying to find the problem. The last year I had water in drive bottle in that side. So pulled the drive Nd had new seals put in. Do you think if the o ring in the drive was pinched it could pull enough air to make my water pressure fall on its face. I opened sea strainers and made sure it was clear and checked all hoses on the intake side . I just put the drive ( cavitation plate ) deep in a barrel and tried it. Same effect. Just wondering if that o ring could be the factor |
Are you having overheating problems, or just low water pressure problems? My gauge lines get crud in them also scale over the fitting inside the block and oil cooler. These result in low pressure readings, but I never have heat related issues.
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I do have it running hotter. To be clear I have 9psi in one motor and 4psi in the other at 3500 . I can’t run over 50mps for a long time without water and oil temp creeping up . Other motor is fine. I believe it has to be on the suction side. Be then again I pressure sender is in the intake manifold . But I did see while in the barrel Today when I brought it up to 2500 rpm the gauge fell on its face and me sea strainer empties. I changed the hose that runs through the transom On the other side thinking it was that when it was just a tstat. When I did it it wasn’t crusty at all. It was a fresh water boat. I think it may be the O ring in the drive. |
What engines???
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Originally Posted by Griff
(Post 4699529)
What engines???
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How old are the transom assemblies and are they used in salt water? |
It was a fresh water boat. I did change the hose in the transom in the port side thinking it was a problem with a temp condition but it was tstat. When I changed it it was clean. |
Pull the hose on the oil cooler and check for old impeller pieces or debris.
What kind of water pickups on your drives?? LWP, DWP, Standard?? |
Lwp and never had a impeller come apart on me. I have good flow from flush to through the drive also |
It can still be the raw water pickup hose through the transom. I've got a fresh water boat also but that was the problem, the hose will crush where it take the 90 degree turn thru the transom. You can see the new replacement hoses now have a plastic insert at that point so the hose won't crush anymore.
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Remove suction hose off of pump, install garden hose end in and clamp it tight. Fire up hose and backflush everything to drive. If you have any restrictions you will notice by doing other motor and compare flow rate. Should be the same. If it's o ring should see water leaking in gimbal or drive connection.
good luck brother |
Bravoitis?
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Originally Posted by chartersj
(Post 4699604)
Bravoitis?
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^^^^^^^ fairly clean lake waters that rarely ever happens - I have had maybe a couple of handfuls that has happened to for the local boaters in my area and that is over 30 years. Heavy based mineral content and or ocean water then year that can be an issue.
there is a 1990 Mercruiser SB all about that and it mentions saltwater use. . The poster is in L I -- NY so he prob does boat in salt waters and that would be a good place to check out - the inset has collapsed and or is crudded up causing a inlet water flow restriction |
Originally Posted by BUP
(Post 4699805)
^^^^^^^ fairly clean lake waters that rarely ever happens - I have had maybe a couple of handfuls that has happened to for the local boaters in my area and that is over 30 years. Heavy based mineral content and or ocean water then year that can be an issue.
there is a 1990 Mercruiser SB all about that and it mentions saltwater use. . The poster is in L I -- NY so he prob does boat in salt waters and that would be a good place to check out - the inset has collapsed and or is crudded up causing a inlet water flow restriction |
Changes the intake hose in the drive. It was crusty. Not a fun job. Did it 4 times in two years . Both sides on my boat and did my friends power play . Good thing I’m not fat. But problem solved |
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