Redmax GZ5000

[SnoJetter]

Update: I'm pumping air somehow.

I pulled the bar off the Redmax and fired it up.  It was a couple seconds before oil started flowing and then it was sort of intermittent as there were air bubbles.  It appeared as though it was trying to purge air and at one point it started flowing a steady stream of oil.  But then it went back to a more steady state of burping bubbles.  I rotated the saw from upright to on its side to see if that made any difference and more often than not, the bubbles indicated it was pumping more air than oil.

For comparison sake, I ran my 2152 without a bar.  This one started flowing oil almost immediately upon start up.  And from that point on it was a steady oil flow from idle and at all points while revving (can't rev it much without a B&C; and of course the clutch drum is always turning even at idle when there's no B&C holding it stationary).

It was too nice of a fall day to be inside tearing things apart, so running the test is as far as I got this weekend. I'll remove the clutch and get access to the oil pump and oil line and see what I can find.  With a full oil reservoir, I can't possibly be pulling air from the tank...I wouldn't think.  It must be a leak in the pump itself or a bad seal between pump and oil line.  I've had these pumps in my hand before, but never looked at them closely to see where they might suck air.  Are they rebuildable?

Any insight into where the air is likely coming from?

[Spike60]

Boy oh boy, this is one of those I wish you lived closer deals for sure.

Going to wait and read what you find when you pull it apart before making more guesses. oil/air mix kind of indicates the pump is trying to pump something. This what we call a puzzler.

[DHansen]

This reminds me of a Arctic Cat I was having issues with last winter.  Although fuel vs oil.  The fuel pick up line in the tank was floating ontop of the fuel and not submerged an setting on the bottom.  The weight on the line had moved and plastic filter with out the weight allowed the filter to float.  It would draw some fuel, but not enough for good operation.

[SnoJetter]

Good analogy, DHansen.  Being a brand new, yet 4 year old saw, it occurred to me that perhaps the oil pick-up had somehow gotten lodged in a remote corner of the reservoir and then over the years of non-use the line sort of hardened and now won't let the pick-up flop around in the tank.  If it got caught in a spot where an air lock could form, then sure enough it could be pumping more air than oil.  That's just a theory and I haven't investigated anything yet, but it sure seems that filling the oil tank would purge all air out of the tank.

I'm more inclined to think there's a simple leak allowing air to enter the system somewhere in the line.  I'll update when I get back out to the shop...which, sadly, might not be until this next weekend. 

[DHansen]

Just a thought to add to your diagnostic strategy.  And its hard when you don't have the saw in front of you to confirm the information and see the issue.  But just this to add,  If the line has a hole of any size after the pump, it will be a oil leak from that hole.   If the hole is in front of the pump (tank side) it will draw air or cavitate the oil in the line after the hole.  I picked up a 385xp that was a disaster as far as oil leak and oil pump.  The metal line had a damaged area that wore a small hole in the oil pipe.

[SnoJetter]

Here's the update on the oiler.  The short story is it seems to be working now.  For details, keep reading.

I tore everything apart: oiler plate, clutch, pump, and oil line.  I like that this is a one-piece line rather than a 2-piece.  There's the opening for the pump, the oulet and inlet.  Sealing the outlet and the pump opening, I removed the inlet filter and was able to pressurize the line.  It held pressure, so there's no leak in the hose itself.  I cleaned the pump and there was no obvious sign of any damage or anything amiss.  But I don't think a visual inspection is going to reveal much.

I inspected the inlet filter and it seemed fine as well.  I did what every other shade tree mechanic would do and put it to my lips to blow in and suck through to see how it responds to that.  There was some resistance to pull air through the filter, almost like there's a check valve...but a check valve of any type - let alone to block flow TO the pump - doesn't make sense.  So there may have been some blockage inside of the filter itself.  But that quickly cleared up.

There's really nothing else to look at, so without being able to tear apart the pump, I reassembled everything.  Upon firing up the saw, the oil started flowing quickly and there were no air bubbles.  Satisfied this was a definite improvement, I reinstalled the bar and set off to clean up some downed 8" branches from an ash tree that have needed attention.  This is one of those chores that involves a lot of idling, a bunch of limbing, and only a little sustained high speed operation to buck up the meat of the branches.  All told, I probably used up 3/4 tank of fuel and half a tank of oil.  I'd estimate that's at least 4 times as much oil as I used for similar work previously.

This is only one short job, but at least for now I'm satisfied it's working.  My tinkering somehow fixed the problem, though I'm not exactly sure what it was I did.  I'll keep monitoring in case it suddenly is starving for oil again.

Beauty of a saw to look at and use!  I highly recommend getting one if you have the chance.  Every now and then a new one pops up for sale.  The orange and grey versions aren't bad, but you can't beat them in red and black!

[DHansen]

Well done! Thanks for the update.

[Spike60]

Excellent!