I assisted a Canadian couple who struggled with the same problem for a couple of years with various mechanics having no success.it finally resulted in then having to be towed into a harbor during a storm.
They pulled, cleaned and even modified the tank suspecting blockages. They also replaced the Racor housing. They were advised to fit a "day tank" along with many other less than useful suggestions. The solution was to fit the correct filter cassette. Along the way someone (I suspect the husband, who was paranoid about the quality of diesel available in the Indian ocean) had replaced the standard 10 micron with a 2 micron cassette. The vacuum that was created caused air to be drawn in wherever it could, mostly through the seals on the Racor - including the brand new one. It appeared to them, and the mechanics, to be an intermittent problem, but was obviously (with hindsight) related to engine load and filter state. A brand new filter would almost work ok. Yours might not be the same problem although the symptoms sound identical, but if not, hopefully this assists someone else down the line. On 26 Jun 2017 05:33, "Josh Muckley via CnC-List" <cnc-list@cnc-list.com> wrote: I have never had much luck with the Racor 200FG which is the smaller predecessor of the 500. I've completely rebuilt mine with all new o-rings and I always vent it thoroughly but still manage to accumulate air. My first question is why you didn't put the fuel pumps as close to the tank physically and hydraulicly as possible, ie: upstream of the racor? This would ensure that air was constantly being pushed out of any leaking seals by pressurized fuel. Your air leaks would then become fuel leaks and be both manageable and easier to identify. It is also unlikely that leaking fuel would cause the engine to shutdown. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Jun 25, 2017 8:32 PM, "Charlie Nelson via CnC-List" < cnc-list@cnc-list.com> wrote: > > My Beta 28 fuel system has recently developed a penchant for sucking air > into the system somewhere upstream of my electric fuel pumps. (I have 2 > installed in parallel so that I can switch between them if one dies or get > clogged, etc.) > > These pumps are downstream of my Racor 500 30 micron fuel filter/water > separator. The input to the separator goes directly to the pickup tube > assembly on the top of my fuel tank via a diesel fuel hose secured with > hose-clamps--recently installed. (I motored at flank speed for about 8 > hours after the installation without any issues). The tank pickup tube > assembly looks identical to a Moeller Fuel pick-up tube which mounts to the > tank top and has nylon tube which goes straight down into the tank about 12 > inches. > > Something is allowing air to get in since my engine will stall frequently > but randomly. On the first occurrence, I changed both the engine and the > Racor filter. > > When it happened again within an hour of the filter change, I opened the > system at the input to the engine filter and found either frothy fuel (lots > of bubbles in it) or just an empty hose. Since the filters had just been > changed, I figured it had to be a vacuum leak. (I was able to pump fuel > into the line and get the engine started again each time it happened--over > the course of a full day of motoring I would guess that it happened on > average every 1/2 hour). > > I tightened all the clamps and the Racor seal as much as I dared and this > did not prevent the stalls. > > My mechanic is as mystified as I am but will likely check-out/replace both > the Racor entirely and the fuel-pick-up tube. The pick-up tube is original > which makes it about 22 years old. > > My thoughts are the Racor filter or vacuum gauge seals are bad/scored or > just not seated properly OR the pickup tube assembly is leaking at the tank > seal or the nylon tube itself has developed small holes or cracks that > allow air to enter, especially with my fuel pump sucking fuel more > efficiently than was possible with the mechanical pump on the engine (since > bypassed). > > My questions to the list are--am I missing something else that could cause > this? Has anyone else had similar vacuum issues and what was the > cause/solution? > > Thanks, > > Charlie Nelson > Water Phantom > 1995 C&C 36 XL/kcb > > > cenel...@aol.com > > _______________________________________________ > > This list is supported by the generous donations of our members. If you > wish to make a contribution to offset our costs, please go to: > https://www.paypal.me/stumurray > > All Contributions are greatly appreciated! > > _______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated!
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