SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: bonzai272 on July 03, 2020, 06:51:01 PM
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Hey all. Took the boat out for the first time today since getting it and I have 2 issues to address that I need some help with.
1) It ran fine for about 5-10 minutes, then it stalled. I was able to keep restarting it but it would stall right away. I was running on the left fuel tank since that had the most fuel. The valve for the right tank was closed. I decided to open it though, so now both tanks were open. It then started and ran fine to get me back to dock safely. Any idea why this would happen and why opening both fuel tank valves let it run OK again? Could it be a clogged line or something related to the venting of the tanks?
2) My tachometer is reading way high. I set my idle on the garden hose at 1100-1200 RPM using a separate dwell tachometer tool I have, so I know my idle is correct at least, but the tachometer at idle is reading 3000. Then when I was on the water and barely giving it any throttle, it would jump up to its max of 6000 but obviously I wasnt going that fast in reality. I made sure the tach is set for 8 cylinders. I even removed it and made sure the contacts inside were clean. I also cleaned up the signal wire/terminal and the ground wire/terminal, even running a new ground wire, but no change. Possibly just a bad gauge? Im sure its the original from 1977.
Thanks!
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Ended up ordering a new tach so hopefully that fixes it. Will see once I receive it.
Regarding the fuel issue. Im currently removing all the fuel lines so I can replace them along with the fuel filter. When pulling the left tank hose, the same side I had an issue with yesterday, it was full of trash and rust. Now Im hoping there is a way to flush the tank without removing it as it is glassed in. Anyone have any suggestions?
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Maybe siphon the tanks empty, then put a few gallons of some type of chemical or cleaner in there, such as alcohol, then siphon that out and keep repeating until clean?
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X2 get or build a siphon with a large enough tube for your debris
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Also perhaps a filter before the fuel pump and after
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Thanks for the help. Man, I feel defeated today. I drained one of the tanks via siphon but I cant imagine how clean I can get it without removing it, which Id really like to avoid.
I did already replace the fuel filter, which is after the fuel pump. I also replaced the fuel water separator. I wonder if I added another fuel filter, before the fuel pump like you said, if that would help catch more sediment or debris and allow the engine to keep running properly. Im sure Id have to replace both fuel filters often until the tanks eventually clean themselves up though, which Im OK with if that sounds like a decent solution...does it?
Otherwise, Im out of ideas. I wish there was some type of service or method where someone could somehow clean and flush the tanks for me without removing them from the boat. Does anything like that exist?
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I went through the same thing with a couple old boats. I bought a cheap electric fuel pump and wired it so I could easily clip it on and off the battery. The fuel pump pulled from the tank pickup and dumped into the fill. I'd let it go for good while and it seemed to work. I would tilt the bow up to wash the fuel to the rear.
Hope that helps!
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I just discovered that same idea online. The fuel pump and fittings should be here tomorrow. Gonna lift the bow and like you said, draw fuel from the pickup, send it thru a couple inline fuel filters, then dump it back into the fill. Ill keep this going until it looks to be cleaner. Maybe I can try to slosh the fuel around in the tank to try to move any sediment closer to the pickup tube.
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Good idea
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Just following up on this.
New tachometer installed and working properly now, so confirmed the original tach was just bad.
Also, I rigged up the inline fuel pump idea with a clear plastic fuel filter on the suction side and the pressure side. I ran it on the left fuel tank for several hours one day while I was working on the trailer. The filters got very dirty so obviously it seemed to be working. After a few hours, I replaced both clear filters with new ones and ran it again. This time they didnt really get dirty, so I called that tank clean and moved to the right fuel tank. That one wasnt very dirty so I just ran it for a couple hours and called it clean.
Havent taken boat out yet but already running much better on the garden hose. Just wanted to share the outcome in case anyone else runs into this and wants to give it a try.
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Great job congrats.
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