Converted MS290 from .325 to 3/8, Now Gushing Oil

[Pulp Friction]

I have been wanting to convert my Stihl MS290 saw over to 3/8 so that I can grind chains for my MS441 without changing wheels, and standardize on 33RSC chain. So today I bought the same style Stihl 20" Rollomatic-E bar (pn 300 3008 8921) but for 3/8" chain. I also switched from the old drive sprocket style to the rim & drum style (pn 1125 007 1002). When done putting on the new parts and chain (33RSC72), I revved the saw half throttle for a minute or two to get oil down the bar onto the chain. I was looking for the tell-tale spray pattern on the ground but did not see any. Instead it started dripping heavily from under the bar-nut region and the top of the bar closest to the saw. I pulled off the bar and chain and it appeared to be coming out of where it should, but was all over the clutch and everything in that area. I've never seen it oil so heavily before and come out of anywhere but the bar. I re-assembled it and verified that the bar sealed up nicely against the slotted oil outlet on the saw but it continued over oiling again. Can someone say for certain if the MS290 was meant to accept the bar, chain and rim/drum sprocket that I put on it?

I was told that the difference between the two bar numbers I was debating between from 2 separate dealers (3003 000 8921 AND 3003 008 8921) is that the "008" bar that I bought was made in Germany and the "000" is identical but made in the states. Hopefully this German bar is not part of the problem. Thanks.

 

[oscar4883]

Is the oil hole on the bar clear of any type of debris? Excessive powdercoat or something similiar cloging the hole maybe?

 

[Pulp Friction]

I'll have to check the bar's oil ports like you said, thanks. Anyone know if this combo goes together?

 

[caleath]

You might want to look and make sure you didnt knock the oil line loose from the bottom of the oil pump.

 

[super3]

Anyone know if this combo goes together?

Yep.

 

[SawTroll]

I'll have to check the bar's oil ports like you said, thanks. Anyone know if this combo goes together?

If you have to check, that is not a good sign!

Anyway, I don't think changing a MS290 to 3/8" is a good move at all - it is a pretty weak saw for its size......

 

[MNfarmer]

Anyway, I don't think changing a MS290 to 3/8" is a good move at all - it is a pretty weak saw for its size......

My 290 with 3/8 pitch is slower than my 440 but it still cuts fine. Doesn't mean it's a bad saw!

 

[mtngun]

I'm sure the OP already knows this, but just to rule it out ...... when installing the clutch drum, make sure the notch in the drum engages the oil pump spring.

If the spring does not engage, it will be bent back and will rub against the oil pump, possibly tearing up the pump or even the crankcase. It also pushes the drum outward and can cause the e-clip to pop off.

I doubt if that is the OP's problem, but just thought I'd throw it out.

 

[Pulp Friction]

If you have to check, that is not a good sign!

Anyway, I don't think changing a MS290 to 3/8" is a good move at all - it is a pretty weak saw for its size......

The reason I'm doing this is to be able to sharpen for both saws quicker and more efficiently without changing grinding wheels and being able to buy bulk chain of the same type for both the MS290 and the MS441. That added efficiency and always having a freshly sharpened chain should make up for the slower saw.

Besides, before I took off the .325" pitch chain I had 45 cutters in the 20-inch loop, about half of them in contact with the wood. With the 3/8-pitch loop I now have 40 cutters, and half of them dragging the wood. Would not a few less cutters in contact with the wood give a saw less strain? I could always leave the rakers at .020" if the new chain loads down the saw a bit more but somehow I doubt I'm going to notice it much.

 

[Pulp Friction]

I'm sure the OP already knows this, but just to rule it out ...... when installing the clutch drum, make sure the notch in the drum engages the oil pump spring.

If the spring does not engage, it will be bent back and will rub against the oil pump, possibly tearing up the pump or even the crankcase. It also pushes the drum outward and can cause the e-clip to pop off.

I doubt if that is the OP's problem, but just thought I'd throw it out.

Don't be so sure, as I've never changed one before. It did sound different when spinning but I thought is was due to the larger chain. Do you have links to illustrations of this oil-pump spring and notch in the drum? In the meantime I'm going out to the garage to dismantle and take a look. Thanks.

 

[mtngun]

I don't have a link handy, but once you pull the drum off and stare at it for a minute, it's pretty obvious. The issue bit me a few times before I started paying attention.

 

[caleath]

I tried to take a picture...its hard to see....

There is a notch in the drum, there is a wire behind the clutch that is attached to the oil pump. The notch is supposed to capture the wire and spin the oil pump. There is a hose that goes from the oil tank to the bottom of the pump. If you get the wire out of whack its possible that it disengaged the hose. To get to it you have to remove the clutch. Its left hand threaded so lefty tighty righty loose....I think its 19mm but dont hold me to it.

 

[Pulp Friction]

I don't have a link handy, but once you pull the drum off and stare at it for a minute, it's pretty obvious. The issue bit me a few times before I started paying attention.

Thanks for all the help. About to go out now and check. One thing I would like to mention though. I WAS getting oil out of the saw's slot that lines up with the bar. If the clutch-drum notch wasn't lined up with the spring, would it pump at all? It almost seems like I have "too much" oil.

Another thing worth mentioning is that the colored dots on the bar are green. I'm using yellow non-safety chain. I don't recall what color the MS290's original bar was. Do the colors have any impact on the oil-slits in the bar? Probably a stupid question, as it seems the bar's slot look like it lines up. Is there an oil hose I could have cut causing excess oil to come out more than one place? I only took off the one drum, greased the needle cage, and put on the new sprocket/rim combo, not knowing there was a spring and drum slot to line up. Sounds like I got lucky with that part though?

 

[caleath]

Bar shouldnt matter...I wouldnt think to get that much oil something is amiss.

Good luck getting it to work...like I said its not easy to photograph without removing the clutch.

 

[SawTroll]

My 290 with 3/8 pitch is slower than my 440 but it still cuts fine. Doesn't mean it's a bad saw!

"Cuts fine" is up to anyone to define, and doesn't mean that there aren't better options!

 

[lambs]

I think I'd have gone with 18" bar on the 290

I didn't note whether you intended to swap bars between your two saws, but otherwise I would have recommended an 18" bar with the 3/8 chain. I ended up selling my 029 Super with a 20" .325 bar because I didn't think it really had the power it needed to pull that bar. But then again, if you don't intend to bury it 20" deep in wood, you should be fine, and you'll have a little extra reach when limbing.

It's always a trade off. I grind some chain for a gentleman who runs an 18" bar on a Stihl 046. So I say do what you want, and let us know how it works.

 

[kugss]

Thats funny i did the same swap on the same saw for the same reason and i dont think im getting enough oil.

 

[caleath]

Wow he ask a question about an oil leak and folks have to chime in on how he has made a mistake in choosing the b/c he did. No wonder I dont venture out here much anymore. Lets just help him fix his problem and not pass judgment on his choice.

I still think its something with your pump or hose. I hope you get this fixed, and ignore the others that cant seem to just help instead.

I have a 3/8ths chain on mine and on two others that I have built. All three with 18 inch bars.

 

[caleath]

Thats funny i did the same swap on the same saw for the same reason and i dont think im getting enough oil.

I am not sure if you know or not that the pump is adjustable.

 

[kugss]

I am not sure if you know or not that the pump is adjustable.

I never seem to rember that till im out cuttin