Hello everyone. I've been reading this forum for the better part of 8 years. I finally need to ask a question, so I created an account.
I had a disagreement with one of my cousins' friends yesterday and I want to ask the experts on here for an opinion. I know that one of you guys knows the answer to this question.
He has been trying to fix a low sea water pressure problem on his boat for a couple of weeks now. According to him, at the end of last season he had a normal 3 psi at idle and around 11-14 psi at cruise RPM. He paid a friend of his to change the impeller in his water pump a couple of weeks ago prior to his first run of the season just because he didn't have the time, and it hadn't been changed in a couple of years. Shortly after doing the work, his friend gets deployed to an 'unknown' location. He can't be reached anytime soon. He took the boat out a few times and all seemed well until his last run of his last outing. He said that he gave it WOT to see how it was running and when he got to about 3900 RPM, by his description, Guardian mode kicked in. He says it runs fine at lower RPM, but "dies" before hitting 4000 RPM every time. He had someone scan it for him, and the code was low sea water pressure. He took it for another ride, and says that he only has about 1 psi of sea water pressure at idle and 5-6 max at cruise RPM. Since then, he's replaced the new impeller with another new impeller. Then, he replaced the front pump housing due to the"scoring". There was no scoring in the old housing that he showed me. It had polished concentric circles that I couldn't even feel by scraping with my fingernail. He pulled his drive earlier in the day and visually verified that the water intake hose was not collapsed at the gimbal housing. He had the engine hatch open and I was just looking around when I believe that I spotted the cause of his problem. There are 2 sets of air lines that come off of the assembly with the relief valve and the valve that you put the air pump on to drain the water system. The set of lines that go to the port side are connected to a housing, and look normal to me. On the starboard side, the air tubes were just hanging there, not connected to anything. I know that they just plug right into the little quick connect fittings on the side of the drain valve housing, so I pointed that out to him. He got in the engine compartment and took a look at it. I tried to tell him how to reconnect the air tubes, but he just couldn't seem to figure out what I was trying to tell him. Finally, I got in there to do it for him. I found why he couldn't do it. The 2 quick connect fittings that I was telling him to push the tubes into are not installed on his drain valve housing. He has the threaded holes, but no fittings. I'm finally at the question. I'm telling him that without those fittings in the drain housing, air can get sucked in through the empty hole on the intake side and cause his low pressure issue. He says that he doesn't think that could be his problem.
Am I right? can air get sucked past whatever guts are in the drain assembly and into the intake side of the pump if the air fittings aren't installed? It just seems to make sense to me. My advice was to either replace the fittings that should be there and connect the air tubes, or at least put a bolt in the holes to block them off.
I had a disagreement with one of my cousins' friends yesterday and I want to ask the experts on here for an opinion. I know that one of you guys knows the answer to this question.
He has been trying to fix a low sea water pressure problem on his boat for a couple of weeks now. According to him, at the end of last season he had a normal 3 psi at idle and around 11-14 psi at cruise RPM. He paid a friend of his to change the impeller in his water pump a couple of weeks ago prior to his first run of the season just because he didn't have the time, and it hadn't been changed in a couple of years. Shortly after doing the work, his friend gets deployed to an 'unknown' location. He can't be reached anytime soon. He took the boat out a few times and all seemed well until his last run of his last outing. He said that he gave it WOT to see how it was running and when he got to about 3900 RPM, by his description, Guardian mode kicked in. He says it runs fine at lower RPM, but "dies" before hitting 4000 RPM every time. He had someone scan it for him, and the code was low sea water pressure. He took it for another ride, and says that he only has about 1 psi of sea water pressure at idle and 5-6 max at cruise RPM. Since then, he's replaced the new impeller with another new impeller. Then, he replaced the front pump housing due to the"scoring". There was no scoring in the old housing that he showed me. It had polished concentric circles that I couldn't even feel by scraping with my fingernail. He pulled his drive earlier in the day and visually verified that the water intake hose was not collapsed at the gimbal housing. He had the engine hatch open and I was just looking around when I believe that I spotted the cause of his problem. There are 2 sets of air lines that come off of the assembly with the relief valve and the valve that you put the air pump on to drain the water system. The set of lines that go to the port side are connected to a housing, and look normal to me. On the starboard side, the air tubes were just hanging there, not connected to anything. I know that they just plug right into the little quick connect fittings on the side of the drain valve housing, so I pointed that out to him. He got in the engine compartment and took a look at it. I tried to tell him how to reconnect the air tubes, but he just couldn't seem to figure out what I was trying to tell him. Finally, I got in there to do it for him. I found why he couldn't do it. The 2 quick connect fittings that I was telling him to push the tubes into are not installed on his drain valve housing. He has the threaded holes, but no fittings. I'm finally at the question. I'm telling him that without those fittings in the drain housing, air can get sucked in through the empty hole on the intake side and cause his low pressure issue. He says that he doesn't think that could be his problem.
Am I right? can air get sucked past whatever guts are in the drain assembly and into the intake side of the pump if the air fittings aren't installed? It just seems to make sense to me. My advice was to either replace the fittings that should be there and connect the air tubes, or at least put a bolt in the holes to block them off.
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