I had bought a 288xp on Ebay in 2011 and had to do some maintenance, etc and all was well with the exception of the oil pump. After taking the thing apart several times and several posts about oiling problems, I have solved the problem and decided to take some pics and offer some narrative as others will likely find issues in the future and this will certainly help.
To get to the oil pump do the following:
1) remove the top saw cover and clutch side cover
2) remove the plug
3) install piston stop
4) remove clutch, clutch drum, clutch bearing, drive sprocket
At this point you will see the oil pump (which has 3 small hex bolts that fix it to the case), the black plastic worm gear, and the oil output adjust screw. Remove the 3 bolts and gently pry the pump out (you will see a top and bottom gap that you can put a screwdriver in .... pry the bottom some, then the top, etc, and it will pop right out. The worm gear will come out (spin it counter clockwise and lift with screwdriver and it will come out (just be careful to not damage it as it has threads you will see on a future photo). There is a pretty large washer behind the worm gear so remove it as well. Crankbearing will now be exposed. Anyhow, back to the oil pump and its internal pieces and how it works.
Pic 394: This is the oil pump view from the side ..... you will see two holes. One is where the actual plunger/piston mechanism slides (the larger hole) in the pump and the other one is where a machined screw will be placed. This machined screw is what will be put in after the plunger/piston is inserted and will actually act like a pin that makes the plunger/piston actually move to the right when the worm gear threads turn the splines on the plunger/piston
Pic 395: a pic of the oil pump .... you can see the three holes for the hex bolts and the oil adjust output screw (I should have had this as the first pic, so my bad)
Pic 396: this is the plunger/pump piston taken out and in pieces. An "endcap" with a hole, the plunger/pistion with splines, a spring, and two washers. Note too, that the machined screw is up at the tops
Pic 397: This is what the plunger/piston pump looks like when assembled and ready to be inserted into the pump housing
Pic 398: Here you can see how, when inserted from the side, the machined screw tip actually fits between the "endcap" and the actual "spline" part of the plunger/piston. Note the angle where the splines start and the position of the tip of the machined screw.... this is critical to get correct when installed as it is what will cause the plunger/piston to actually catch (the tip of the machined screw) on each revolution and cause the plunger to actually move to the right (compressing the spring) and then the piston will move to the left when the tip of the machined screw is not impeded when the angle piece completes the rest of the turn (hopefully this made sense). Note: If you cannot spin the plunger/piston with your finger, you have this screw too tight.
Pic 399: This is the plunger/piston and machine screw (not visible in this pic) installed. Note the spring on the right side and study the gap width where the spring is.
Pic 400: you can now see as I spun the plunger/piston splines with my finger, the tip of the machined screw "got in the way" of the angled piece of the plunger/piston so it actually moves it to the right, thus compressing the spring. Note here you can see a small "gap" to the left of the splines and then the "gap" on the right is smaller than in pic 399 ..... this is to show you how the plunger/piston moves left and right inside the pump. If you do not have this result, something is not installed right.
Pic 401: This is the oil output adjustment screw with a little o-ring on it. Note the "scalloped/canoe cut out-esqe" edges of different sizes (here you can only see two, but a 360 degree view shows a total of four for the four bar oil output settings [from smallest to largest]. More on inserting this screw on the next step
Pic 402: This is the oil adjustment output screw installed. A few notes here. Before you put it in, look in the hole and you will see the end of the plunger/piston partially sticking through. This is what "rides" in the scalloped/canoe-esque cut outs on the screw. Second, note the "dot" on the end of the screw top. This is what "setting" you are currently on. Note on the pump body, there is a stamped 1, 2, 3, and 4 in a counter-clockwise form (North, South, East, West format with 1 being East). I installed the screw with the dot lined up with the 1 and then each turn in and tightened a few revolutions beyond the oil ring (when it "seats" in the pump body). You can actually feel this screw "click" into the scalloped edges as it is turned..... and do not tighten too much. One other note, there is not such setting as 1.5, or 2.5, or 4.75, etc .....this is due to the scalloped edges being what they are. In fact, if you tried to set it at say 1.5, it would put oil even less oil than 1.0
Pic 403: I installed everything and did a test run and note, you can see bar oil where it should be.
One last comment about this project on some things I did not discuss first. There is an oil line with a brass colored perforated filter in this oiling process. When you take the pump cover off, you will see a rubber line end at the bottom right (if you pull this out, the brass filter will come right out too). I took this out and made sure it was not cut or blocked. Also, there is a tiny O-ring on the back of the pump. It goes back into the saw case and through a channel to the guidebar channel. Hope this helps someone. View attachment 229751View attachment 229752View attachment 229753View attachment 229754View attachment 229755
To get to the oil pump do the following:
1) remove the top saw cover and clutch side cover
2) remove the plug
3) install piston stop
4) remove clutch, clutch drum, clutch bearing, drive sprocket
At this point you will see the oil pump (which has 3 small hex bolts that fix it to the case), the black plastic worm gear, and the oil output adjust screw. Remove the 3 bolts and gently pry the pump out (you will see a top and bottom gap that you can put a screwdriver in .... pry the bottom some, then the top, etc, and it will pop right out. The worm gear will come out (spin it counter clockwise and lift with screwdriver and it will come out (just be careful to not damage it as it has threads you will see on a future photo). There is a pretty large washer behind the worm gear so remove it as well. Crankbearing will now be exposed. Anyhow, back to the oil pump and its internal pieces and how it works.
Pic 394: This is the oil pump view from the side ..... you will see two holes. One is where the actual plunger/piston mechanism slides (the larger hole) in the pump and the other one is where a machined screw will be placed. This machined screw is what will be put in after the plunger/piston is inserted and will actually act like a pin that makes the plunger/piston actually move to the right when the worm gear threads turn the splines on the plunger/piston
Pic 395: a pic of the oil pump .... you can see the three holes for the hex bolts and the oil adjust output screw (I should have had this as the first pic, so my bad)
Pic 396: this is the plunger/pump piston taken out and in pieces. An "endcap" with a hole, the plunger/pistion with splines, a spring, and two washers. Note too, that the machined screw is up at the tops
Pic 397: This is what the plunger/piston pump looks like when assembled and ready to be inserted into the pump housing
Pic 398: Here you can see how, when inserted from the side, the machined screw tip actually fits between the "endcap" and the actual "spline" part of the plunger/piston. Note the angle where the splines start and the position of the tip of the machined screw.... this is critical to get correct when installed as it is what will cause the plunger/piston to actually catch (the tip of the machined screw) on each revolution and cause the plunger to actually move to the right (compressing the spring) and then the piston will move to the left when the tip of the machined screw is not impeded when the angle piece completes the rest of the turn (hopefully this made sense). Note: If you cannot spin the plunger/piston with your finger, you have this screw too tight.
Pic 399: This is the plunger/piston and machine screw (not visible in this pic) installed. Note the spring on the right side and study the gap width where the spring is.
Pic 400: you can now see as I spun the plunger/piston splines with my finger, the tip of the machined screw "got in the way" of the angled piece of the plunger/piston so it actually moves it to the right, thus compressing the spring. Note here you can see a small "gap" to the left of the splines and then the "gap" on the right is smaller than in pic 399 ..... this is to show you how the plunger/piston moves left and right inside the pump. If you do not have this result, something is not installed right.
Pic 401: This is the oil output adjustment screw with a little o-ring on it. Note the "scalloped/canoe cut out-esqe" edges of different sizes (here you can only see two, but a 360 degree view shows a total of four for the four bar oil output settings [from smallest to largest]. More on inserting this screw on the next step
Pic 402: This is the oil adjustment output screw installed. A few notes here. Before you put it in, look in the hole and you will see the end of the plunger/piston partially sticking through. This is what "rides" in the scalloped/canoe-esque cut outs on the screw. Second, note the "dot" on the end of the screw top. This is what "setting" you are currently on. Note on the pump body, there is a stamped 1, 2, 3, and 4 in a counter-clockwise form (North, South, East, West format with 1 being East). I installed the screw with the dot lined up with the 1 and then each turn in and tightened a few revolutions beyond the oil ring (when it "seats" in the pump body). You can actually feel this screw "click" into the scalloped edges as it is turned..... and do not tighten too much. One other note, there is not such setting as 1.5, or 2.5, or 4.75, etc .....this is due to the scalloped edges being what they are. In fact, if you tried to set it at say 1.5, it would put oil even less oil than 1.0
Pic 403: I installed everything and did a test run and note, you can see bar oil where it should be.
One last comment about this project on some things I did not discuss first. There is an oil line with a brass colored perforated filter in this oiling process. When you take the pump cover off, you will see a rubber line end at the bottom right (if you pull this out, the brass filter will come right out too). I took this out and made sure it was not cut or blocked. Also, there is a tiny O-ring on the back of the pump. It goes back into the saw case and through a channel to the guidebar channel. Hope this helps someone. View attachment 229751View attachment 229752View attachment 229753View attachment 229754View attachment 229755
