Sigh...Yes Another Poulan Question

[BentWrench1]

Well my step son was gifted an older Poulan 2150 LE Woodsman. Since I've been repairing several small engines and chainsaws in the past few years as well as being the family mechanic he asked me to check it out. Being hesitant, and warning him about Poulan's reputation we agreed to limit the repair costs.

So after the usual Carburetor/ Tune Kit, and Oil Pump parts I have it running pretty good with the exception of the infamous over-oiling condition. Now I read that's pretty common with these and even saw "the fix" where a set screw is installed into the oil pick up elbow allow to choke down the uptake of oil. So, that gave me an idea. I removed the elbow and inserted a small length of ball point pen tubing, flaring the end with a hot nail. This made the orifice approximately half the original size. It still seemed to over produce oil! So now I've drained the "All Season" bar and chain oil out and replaced it with 80w 90 Gear Oil.

Hoping the experience of the forum members reading this could chime in. Is this best I can hope for on this saw?

 

[hotshot]

That’s about all you can do, just don’t want the saw to run out of bar oil before the fuel does. When cutting dead trees/limbs, a lot of oil is needed versus idling & piss revving on your work bench.

Tractor supply (TSC) had the thickest bar oil, according to an old Texas A&M student paper.

https://www.arboristsite.com/attachments/bar-oil-cost-benefit-analysis-redacted-pdf.648852/

 

[BentWrench1]

That’s about all you can do, just don’t want the saw to run out of bar oil before the fuel does. When cutting dead trees/limbs, a lot of oil is needed versus idling & piss revving on your work bench.

Tractor supply (TSC) had the thickest bar oil, according to an old Texas A&M student paper.

https://www.arboristsite.com/attachments/bar-oil-cost-benefit-analysis-redacted-pdf.648852/

Hey hotshot thanks for the reply and the very interesting study and test results! I guess my biggest issue is out of all the saws I've worked on this one marks it's spot pretty aggressively. And me being OCD I don't like to see a mess in the bottom of it's storage case.

 

[Tomos770]

You can alter oil delivery by contracting that spring that drives the pump on the crank...

 

[cookies]

the red max bar oil sold through and at walmart is super thick stuff, I typically mix 20% hydraulic oil in with it during summer and its still thick. When I run saws I time how long I run them between refueling and stop at 30 minutes to avoid running out of fuel during longer cuts, I suggest the same.

 

[BentWrench1]

You can alter oil delivery by contracting that spring that drives the pump on the crank...

By the spring I assume you mean the worm gear drive? I thought it had to match the gears on the pump or it would destroy the plastic gear. You're saying squeeze the "spring" tighter? Please explain.

 

[Tomos770]

By the spring I assume you mean the worm gear drive? I thought it had to match the gears on the pump or it would destroy the plastic gear. You're saying squeeze the "spring" tighter? Please explain.

Yes worm gear....better word.

I have Partner 351 chainsaw.....which is basically Poulan 2x5x....

Its oil pump (or worm gear) is basically like a small spring which is spining on the shaft. And which further on drives...not plastic gear...but splined shaft (metal shaft has plastic/rubber insert with splines on it)

Cant find propper words/termins....but imagine sinus wave on a graph.....by changing its "Period" you can tweak how fast that will spining the oil shaft....

 

[Old2stroke]

Yes worm gear....better word.

I have Partner 351 chainsaw.....which is basically Poulan 2x5x....

Its oil pump (or worm gear) is basically like a small spring which is spining on the shaft. And which further on drives...not plastic gear...but splined shaft (metal shaft has plastic/rubber insert with splines on it)

Cant find propper words/termins....but imagine sinus wave on a graph.....by changing its "Period" you can tweak how fast that will spining the oil shaft....

Good idea but have you actually tried this and can you get any appreciable change in oil delivery? Squeezing the coils of the worm gear together more should give you more oil not less and if you get the coils so tight that more than one loop is in contact with the splined unit, you will get pitch interference.
Why did you show the chain tensioner screw rather than the splined shaft?

 

[Breckinridge Elkins]

...So now I've drained the "All Season" bar and chain oil out and replaced it with 80w 90 Gear Oil....

Surely the oil puddle can't be worse than the stink from gear oil?

 

[BentWrench1]

Good idea but have you actually tried this and can you get any appreciable change in oil delivery? Squeezing the coils of the worm gear together more should give you more oil not less and if you get the coils so tight that more than one loop is in contact with the splined unit, you will get pitch interference.
Why did you show the chain tensioner screw rather than the splined shaft?

I agree with this in thinking a expanded spring would slow the oil pump and not a compressed spring. Also, how do you compress a spring anyways? Heat is the only thing that would really work (think lowering an old car's coil springs with a torch). Also since it's metal set at the same distance as the plastic drive gears on the pump I'd be worried about just destroying the plastic. That BTW is the number one reason you replace the Oil Pump on one of these, the plastic gear gets a flat spot and no longer spins.

 

[BentWrench1]

Surely the oil puddle can't be worse than the stink from gear oil?

LOL! I considered the smell but when I opened the bottle it didn't stink like it does when you drain a differential. Besides, my step son and grandson will be using it and not me! There's a method to my madness... Bwaaa haa ha!

 

[Tomos770]

Good idea but have you actually tried this and can you get any appreciable change in oil delivery? Squeezing the coils of the worm gear together more should give you more oil not less and if you get the coils so tight that more than one loop is in contact with the splined unit, you will get pitch interference.
Why did you show the chain tensioner screw rather than the splined shaft?

I didnt know that special tool for installing that spring actually exist....@6:00



When I did my oil pump I went like in this video @5:20....



I did inspect after wether spring turns the shaft properly and that was it...

But I do notice that after that oilpump delivers more oil then when it had OEM settings....so I asume that I somehow tweaked it unintentionally when I fiddled with that spring/coil

 

[BentWrench1]

The spring coils have to match the spline gears on the pump IMHO. The factory pump I removed was flat in one spot. A worm gear onto a spline gear can only work by either matching, or stretching the coils until only the end (one with the curve) catches a spline once every revolution.

 

[Okie]

You asked:
Hoping the experience of the forum members reading this could chime in. Is this best I can hope for on this saw?

Most likely a big YES.

Let it oil.
I would just use the thicker summer grade oil and let it do it's thing.
Tell the Operators to check the oil reservoir before the saw runs out of gas.

You might get a surprise that the oiling is actually normal for the amount of gas used when cutting wood.
Also those will seem to be over oiling because the oil pump is running when the saw is idling. Better too much oil than not enough.

I've seen some saws, usually the smaller cheap made saws that I have to thin the oil with little diesel or add a lighter weight oil to get good chain oiling, especially in cold weather.

This oiling issue is one reason why Stihl has a summer grade thicker bar oil in the orange jug and a thinner winter grade bar oil in the blue jug.

 

[Old2stroke]

The spring coils have to match the spline gears on the pump IMHO. The factory pump I removed was flat in one spot. A worm gear onto a spline gear can only work by either matching, or stretching the coils until only the end (one with the curve) catches a spline once every revolution.

My thoughts exactly. Stretching the coils should work but whether it would make much of a difference is the question and there is limited space behind the clutch so not sure how much it can be stretched.
Over oiling can be cured to some degree by changing the viscosity of the oil and I guess restricting the size of the pick up tube but restricting the output of the pump is something that shouldn't be done, puts back pressure on the pump and makes the splined part harder to turn, ends up getting stripped. I think this is the main reason the splines get stripped, lack of maintenance causes plugged oil passages in the bar and nowhere for the oil to go.
It's been awhile since I had one of these apart but I think the oil pump piston/plunger is held in by a plug and the length of the plug determines how far the piston travels and thus, how much oil it pumps, changing this distance is how adjustable oilers work so just placing a small spacer on the end of the plug to shorten the travel of the piston should be a good way to reduce oiling. I think this is why some saws oil too much, quality control slips and the plug is too short or not seated properly. Have to have a better look next time I have one apart.

 

[Tomos770]

In past 4yrs.....I bougt first Husqvarna 450mk2....then 550xp mk2....

450....I had to rebore its oilpump from OEM pickup hole of 1.5mm to 2.5mm.....and put additional hole on its bar....now oiling of the bar is sufficient...

550xp mk2....oiler is on MAX....didnt fiddle with it yet....would like to have more oil on its bar

Partner 351....after I rebuilt its oilpump....there is generous amout of oil on the bar....if it is idling for a minute....when I blip its throttle it trows (residual) oil everywhere...yes oilpump works @idle VS non working pump @450&550

 

[BentWrench1]

I consider a puddle the size of a pancake under the saw when you set it down to be too much.

 

[BentWrench1]

My thoughts exactly. Stretching the coils should work but whether it would make much of a difference is the question and there is limited space behind the clutch so not sure how much it can be stretched.
Over oiling can be cured to some degree by changing the viscosity of the oil and I guess restricting the size of the pick up tube but restricting the output of the pump is something that shouldn't be done, puts back pressure on the pump and makes the splined part harder to turn, ends up getting stripped. I think this is the main reason the splines get stripped, lack of maintenance causes plugged oil passages in the bar and nowhere for the oil to go.
It's been awhile since I had one of these apart but I think the oil pump piston/plunger is held in by a plug and the length of the plug determines how far the piston travels and thus, how much oil it pumps, changing this distance is how adjustable oilers work so just placing a small spacer on the end of the plug to shorten the travel of the piston should be a good way to reduce oiling. I think this is why some saws oil too much, quality control slips and the plug is too short or not seated properly. Have to have a better look next time I have one apart.

"restricting the output of the pump is something that shouldn't be done, puts back pressure on the pump and makes the splined part harder to turn, ends up getting stripped."

I restricted the intake or suction end by making the orifice smaller. That way the pump can run unrestricted with no pressure against it.

 

[a. palmer jr.]

I have a metal work table that will never rust because I sit my chainsaws on it sometimes..