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TurtleWoods72

New MS391 not oiling chain!

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Two questions.

 

Would the fact I'm using half to two thirds throttle effect this oiling malarkey ? As I'm running the saw in as per the manual.

 

How the hell is oil getting on the exhaust and running down the outer side of the clutch cover?

 

I'm beginning to think the bar is the culprit...?

 

Also, I read on some US sites that the MS390 was prone to this problem. Several owners reported being told they'd broken off an 'oil plug' and had fixed it by inserting a machine screw with sealant tape into 'a hole between the exhaust and bar' which I'm unable to locate.

 

 

Yes, do not run at half or 2/3 throttle! You'll glaze the bore, then it'll run like a complete turd! Run it like you stole it!

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Sounds like B&C tension is fine. Run the saw full throttle or not at all. 2 strokes ain't designed to be feathered.

 

The bar and chain are fine, as was the tension like you point out.

 

The Stihl owners manual urges you not to run the engine at full revs for the first three tank fills.

 

I know two strokes like to be revved out, I own no less than 14 two stroke machines :thumbup1:

 

Update:

 

I cleaned everything, whacked the oil delivery up to max, and tried revving it. (No bar). Oil dribbled from the oil port, not gushed.

 

Re-fitted bar (all cleaned up and like new) and did the splatter test. When revved hard I got a nice spray pattern on the newspaper. Yes! It's cured I thought.

 

Looked at the saw an oil was literally dripping from the bottom. Bollox.

 

Here's a picture of the mess it left after a few seconds of revving.

 

Plus the bar was scorching hot, as were the nuts on the bar.

image.jpg.979b22e5359165a81f33942007a291df.jpg

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Looks normal. Chains will get got and dust will collect. Drive links look clean.

 

Toughen up, Sally. Go cut some wood!

 

So it's normal for one minutes use to cause dripping oceans of oil to pour from the clutch cover, and the bar nuts to be almost too hot to touch by hand?

 

In that case I'll stick to my Makita/Solo saws, which are cool and clean.

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The Stihl owners manual urges you not to run the engine at full revs for the first three tank fills.

 

 

 

Don't care! It also states that anything other than Stihl oil should be ran at 33:1!

Remember, all the information on how to run in an engine hasn't been updated since old Andreas marketed the BLK blitz. Back then oil was gloopy and ran at 25:1 or worse!

 

Run the engine at full revs in timber! Anything less over-richens the mixture, causing severe coking and glazes the cylinder, meaning the rings don't bed better, decreasing compression and therefore power!

Do as you are told by people who IMPROVE chainsaws!

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You should be running it flat out for shorter periods than you may do for a run in machine.

 

You should be making the most of the new rough rings and bore to wear both to a good fit quickly which will give better compression. If you run an engine in slowly, it will glaze and it will take forever to bed in and make good compression.

 

If you rev a saw in free air, you will get a lot of oil taken back in to the clutch and housing. If you cut wood, the oil is transfered to the wood and you get much less around the clutch. I tach many saws as part of a service and get a lot of residue oil left under the clutch cover.

 

Run the saw in wood and see if the chain stays free running and the drive links slightly damp with oil when lifted out of the bar.

 

It is possible that the oil system had a bit of an air lock and took a while to prime the system.

 

A freshly rebuilt saw takes a little time to pull the oil through!

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You should be running it flat out for shorter periods than you may do for a run in machine.

 

You should be making the most of the new rough rings and bore to wear both to a good fit quickly which will give better compression. If you run an engine in slowly, it will glaze and it will take forever to bed in and make good compression.

 

If you rev a saw in free air, you will get a lot of oil taken back in to the clutch and housing. If you cut wood, the oil is transfered to the wood and you get much less around the clutch. I tach many saws as part of a service and get a lot of residue oil left under the clutch cover.

 

Run the saw in wood and see if the chain stays free running and the drive links slightly damp with oil when lifted out of the bar.

 

It is possible that the oil system had a bit of an air lock and took a while to prime the system.

 

A freshly rebuilt saw takes a little time to pull the oil through!

 

:thumbup: oh thank you Spud! :thumbup:

 

This is what I wanted to hear!

 

All makes sense, the air lock due to newness of the saw, the low revs (screw that) causing minimal oiling, the test runs (not in timber) causing oil to run back into the casing.

 

I will try it in some Oak tomorrow. However, I'm still curious as to why the exhaust was swimming in oil?

 

Surely it's seperated by a lot of plastic?

 

Any ideas on the whole 'grub screw' theory the yanks were using for this problem on MS390's?

 

Seemed to cure all oiling ills on that model, :confused1:

 

Can't find anywhere between exhaust and bar where an 'oil plug' could be missing.

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Two questions.

 

Would the fact I'm using half to two thirds throttle effect this oiling malarkey ? As I'm running the saw in as per the manual.

 

How the hell is oil getting on the exhaust and running down the outer side of the clutch cover?

 

I'm beginning to think the bar is the culprit...?

 

Also, I read on some US sites that the MS390 was prone to this problem. Several owners reported being told they'd broken off an 'oil plug' and had fixed it by inserting a machine screw with sealant tape into 'a hole between the exhaust and bar' which I'm unable to locate.

 

 

I was thinking this.Don't know about the 391,but on the 017/170 there is a coloured plastic plug in the end of the tube , that the oil pump is fitted.I can't find a picture ,but its a little orange piece of plastic on the chain side of the exhaust , and is visable on a clean saw without taking apart.

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