I had some luck with diesel fuel tank cleaner made by starbrite. I would also run a small 12v pump on the far side of the racor, recirculating the fuel back to the tank. I found a pretty cheap one online. Of course, the larger/faster the pump, the more stuff it *may* suck up off the bottom. When I say I had some success, it is only because it is hard to quantify. Our new to us boat had been on the dock for a long time (less than about 50 hours over a 6 year period). We we picking up small granular crud in the bottom of the filter bowl. After recirculating the fuel for 10 hours total time after adding the cleaner, it seemed to stop collecting crud. We then motored a total of 24 hours with no engine issues. A year later with about 75 new hours on the engine I picked up a slight rough running just above idle. I swapped out the filter and it was back to running fine. We have shaken up the tank a few times as well. That said, I say some success as I have no way of saying just how much crud was in my tank to begin with. The reviewson the Starbrite product are very high, however. Hope this helps, Bruce Whitmore 1994 37/40+
Sent from my Verizon, Samsung Galaxy smartphone -------- Original message --------From: Nauset Beach via CnC-List <cnc-list@cnc-list.com> Date: 4/23/18 12:23 PM (GMT-05:00) To: cnc-list@cnc-list.com Cc: Nauset Beach <nausetbe...@optonline.net> Subject: Stus-List Diesel Tank Cleaning All, Last year my engine shut down 2 times and have concluded I need to clean out the diesel tank. I had very old fuel [3+ years] in the tank after several years of very low usage and topping up the tank prior to winter storage which was the cause of the 1st shut down. Most of that fuel was removed, but had a 2nd shutdown which am assuming was due to “crud” blocking the pickup. The Racor was completely blocked the 1st time, but was completely clear the 2nd time, and the engine started right up after being off for 12 hours. Do not think fuel polishing alone would be sufficient. The tank is 20 yo. I know tank cleaning has come up on the list in past years and recall some steam cleaned &/or pressure washed the tank interior. I do not want to introduce water into the tank – do not have sufficient time to drain and dry the tank adequately prior to launch. Nor the ability to readily do that. Have read people used clean diesel as a “solvent” to clean the interior but am wondering if that would really be sufficient. Have also read of using MEK to break down / dissolve deposits in the tank. At this point there is about 5 gal of diesel in a 20 gal tank, a portion of which could be used to slosh around /agitate within the tank, but again am unsure if diesel alone would be sufficient. Any suggestions on how to “quickly and easily” clean a diesel tank? There is a 4” inspection port, but it is screwed in place with self-tapping screws [per the manufacturer] which use a drive shape I am not familiar with – a square with small lines radiating out from each corner – sort of a cross between a Robertson and a Phillips. So am hesitant to remove that plate as a) do not want to strip / round out the screw heads, and b) do not know what type of sealant to use to close it up upon conclusion. Was thinking I could use the pickup or return openings to remove most of the fuel with a manual extraction pump [same as I use for oil changes], and possibly the 1 ½” fill fitting as a way to drain out most if not all of any crud / water that may be in the tank. I can remove the tank from the boat fairly easily so can flip it over to drain out through the fill fitting. Would also check for a screen on the pickup. ThanksBrian
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