If your oil transfer pump is a flexible impeller type, I may have an inkling of what's going on. I use a portable oil evacuation pump, mounted on a 4 gallon bucket, using a Jabsco reversible pump fetted with a nitrile impeller that's oil resistant. I built the setup myself years ago, and have used it a lot.
What I've discovered is that the "oil-resistant" impeller - - isn't. Especially when it's only used occasionally, which is usually the case on pleasure boats - often just one oil change a year. The impeller blades "take a set" in the pump housing, and prolonged exposure to motor oil makes the blades brittle. The pump may work OK - - once - in the direction where it was used last, since it's in the direction that the impeller blades came to rest in. But, one reversal of direction is all it takes for the impeller to shed all its blades, plug up the pump's orifices, and cease to function. I've had this happen several times now that my pump gets intermittent use (as opposed to weekly or daily use when I ran my marine service company) and I've gotten tired of paying $28 apiece for the replacement impellers. Now, I open up the pump and pull the impeller out after each use. Since I use it so seldom, it's no big deal to spend five minutes putting the pump back together before I use it, and another five minutes taking it apart afterward. If your transfer pump is a vane type, with impeller vanes that don't take a set, I'd look for something obstructing the hose or tubing on the side of the pump that becomes the suction side when you reverse the flow. If there's some hose in there that's old, or isn't meant for exposure to petroleum products, the inner lining of the hose can be pulled together by the pump's suction, blocking the flow. If any of that hose seems squishy when you pinch it, that may be what's happening. Or, there could be foreign matter in the hose that allows flow in one direction, but not the other. To test the pump in that direction, pull the hose off the pump and use another piece of hose into a container of fresh lube oil and see what happens... On Sun, Sep 21, 2014 at 5:09 AM, Doug Thomas <[email protected]> wrote: > Another issue arose while doing the oil change yesterday. The Uniflite 46 > has an oil pump to pump the oil from the engines and genset through the > hull where a hose is attached and drains into a bucket dockside. No fuss, > no muss - in theory. It pumped out fine, but when I hit the reverse switch > to pump new oil from an external bucket back into the crankcase, it didn't > happen. The pump was running, but it didn't pump the oil back aboard. > Anyone had this problem and can tell me what I did wrong? Seemed too simple > to have messed up. All appropriate valves were open. > > > > Doug > > -- > You received this message because you are subscribed to the Google Groups > "UnifliteWorld" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/unifliteworld. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "UnifliteWorld" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/unifliteworld. For more options, visit https://groups.google.com/d/optout.
