Stihl 038 Oiler

[Andy171361]

 

  

 

Hello.  I have a Stihl 038 Magnum that leaks oil from the side casing when I use  it.  I have removed the side casing and found that the worm gear actually appears designed to supply oil through the hole in the centre of it.  The part number of this worm gear is 1119 647 1800.  Whereas the part number in the spares list is 1119 640 7100.

Can anybody shed some light on this matter for me please?  And how can I stop the oil leaking from the side plate?

Thank you for your help.

Andy

[ZeroJunk]

Looks like the pin hole got wallowed out somehow. Get one off eBay or where ever and replace it.

[Al_Smith]

The gear really only presses on the worm drive by way of splines .I couldn't find one of my spare pumps but I don't think it's suppossed to have a hole in the middle of the nylon gear .

If I get time after work tomorrow I'll check out one of my 038's .

[sablatnic]

I don't know either, if the hole is supposed to be there, but it often is.
The oil flowing through the hole is oil leaking past the rotor in the oil pump, so the real culprit is not the gear, but the oil pump.
If the pump delivers what the bar and chain needs, and you can live with the spill, there is no reason to use money on a new pump. At least I wouldn't; all chainsaws will spill oil.

[Andy171361]

 

 

Thank you for your 3 replies which are all very helpful.  I have added another photo showing the face of the worm gear.

Zero Junk, you mentioned that the pin hole looks as though it has been enlarged.  Is the pin hole there to allow some oil to spread onto the teeth of the worm gear itself to lubricate them?  That would make sense to me.  In that case I might not be getting oil in the wrong place, just too much of it in the right place!

It seems as though the jury is out as to whether there should be a hole in the face of the worm gear.  Maybe I should email Stihl and ask them about the 2 different part numbers?

Sablatnic, I know what you mean about all chainsaws leaking oil.  I also have an MS361 but that is much drier in comparison.  The good thing about my 038 is that I am getting a really ample supply of oil to the chain and yes, I can live with the oil leak if needs be, so I am not planning on changing the oil pump just yet.

Thanks again for all your suggestions - much appreciated!

[Andy171361]

News flash!!

I have just checked the part numbers on L&S Engineers website (UK). 

Part number 1119 640 7100 is the Worm gear for Stihl 028, 038 etc.
Part number 1119 647 1800 is the worm gear for Stihl 084, 088 etc.

Presumably the bigger saw needs a greater oil supply to its worm gear teeth and so has a bigger hole in the worm gear face?  And interestingly it is £3 cheaper than the 038 part. 

If anybody happens to have part number 1119 640 7100 fitted to their 038 (or 028) I would be very interested to hear whether it has a pin hole or not.

[Al_Smith]

I just looked at an 042 which uses the exact type of oiling system and it does indeed have a hole in it .I never noticed that fact before .

[sablatnic]

Have been out having a look at my 028 rebuild project, and it has the hole in it.

[Andy171361]

That makes sense.  Part number 1119 640 7100 is listed as suitable for: 028 042AV 048 MS381 038 and MS380.  Thank you for checking your saws and confirming that the hole is there.  I think as ZeroJunk said, in the first reply, the next step is to buy the correct part and see if that changes things.

I'll let you know how I get on but in the meantime thanks again for your help.

[HolmenTree]

I've posted this on another site about a leaking 038 oil pump.  30 years ago when I logged with a 038 Mag I had problems with a rubber or plastic (can't remember which) plug dis lodging on the pump.. It appeared back pressure from a plugged bar oil hole popped it out.
Putting a new upgraded plug in fixed the problem.

[Al_Smith]

I've had a plugged oil channal but it never popped the connector .Just didn't squirt enough oil .That was on an 048,never had a problem on the 038's (3).---yet.

[HolmenTree]

Yeah my 38 mag was the 1st year model so I guess the upgraded plug was the answer.
My older 1980 61cc 038 had no oil pump issues.

[Al_Smith]

Actualy that series that used the nylon gear drive pumps was pretty reliable .I had one of which I can't remember that had worn gears .Replaced the gears ,good to go .The saw probabley had a million hours on it by then ,flea bay ya know . ;)

[Andy171361]

Well the new worm gear has arrived and, to my surprise, the hole in the middle is actually wider than the hole in the old part!  I have measured the hole at just under 4mm for the new part, while the hole in the old part is 1.5mm.  I have also studied my 038 workshop manual and that states that the teeth of both nylon gears should be greased before assembly.  So that means my theory about the oil being intended to lubricate the gears is flawed.  Oh well, back to the drawing board!

Now, can anyone tell me what the larger hole, midway between the centre and the rim of the worm gear is for?...

 

[joe_indi]

If you were to look at both wheels from the lower side you will find that the holes are more or less the same. That central hole is for the shaft that sits in the center of the oil pump hole for this gear wheel.This shaft comes loose and could be lost if you are not careful when opening the side cover. If your pump has just a concentric hole in the center that means that oil pump is missing a shaft!
When that happens, the gear wheel tends to jump around ruining the alignment of the pump piston, which in turn wears out the pump body. Final result? Oil flowing from strange locations. If there is no shaft, you need to put some kind of substitute in place.
Joe

[Al_Smith]

I doubt you will ever get it that it doesn't leak at least a little oil .Just the nature of the beast .

Periodically remove the inner cover and blow all the crud out with compressed air .Probabley  run forever .

[Andy171361]

Hello Al and Joe.

I am familiar with the shaft you mention, Joe, and I am pleased to say that I have one.  While I had the saw dismantled I replaced two O rings and one oil seal in the pump.   Having fitted the new worm gear, and then wound the worm gear round and round with my finger (in the mystery hole!), I have proved that oil is definitely coming out of the correct place in the casing to lubricate the chain, but now I can not see any oil coming through the central hole.  To my untrained eye it looks as though the shaft is filling the hole completely.   I realise that when the saw is operating at full speed this might not be the case but from the very first photo I posted on this thread I got quite a decent flow of oil through the central hole by winding the worm gear by hand.  So whether the new oil seals have made a difference, or it is down to the worm gear I can not say.  I am hoping to do some proper cutting with it tomorrow so I will be able to see whether there is a real difference under normal conditions.

And actually Al I think you are right, I doubt I will ever get it completely leak-free.  But if I could get it to about the same state as my MS361 I would be really pleased.

Incidentally, while I was at it I replaced the spur sprocket with a rim sprocket conversion.  All I need now, to make this saw as easy to use and maintain as a more modern Stihl, like an MS361, is a side chain tensioner.  I don't suppose anybody happens to know if an 038 can be converted in this way?

[HolmenTree]

Do the MS380 models sold in other parts of the world have side tensioners?

[joe_indi]

Do the MS380 models sold in other parts of the world have side tensioners?

We have always had side tensioners from the first MS380 that was sold here in India. Even the last of the 038s had them. Now the MS381 has them.

......... All I need now, to make this saw as easy to use and maintain as a more modern Stihl, like an MS361, is a side chain tensioner.  I don't suppose anybody happens to know if an 038 can be converted in this way?

Andy, thats easy and not too expensive to do.The required parts are the same as that for the MS460. See the picture I have given the part numbers for the required parts.
Joe

[ZeroJunk]

Just thinking out loud, but doesn't there have to be a recess in the crankcase and a threaded hole  for 1,5,6,an 7  ?

[Al_Smith]

I've only had problems one time with the gear drive oilers .I got another one off of flea bay only to discover the problem was the suction line from the tank,the pump was fine .048 .No big deal now I have a spare .

[Andy171361]

 

 
Here is a shot of the new worm gear in place and greased with Stihl gear grease.  It shows well that the shaft is filling the centre hole completely. 

I did a fuel tank's worth of cutting yesterday and my first impression is that it is much drier than before.  I'll know for sure once I have got the side casing off. 

Thank you for your help with side tensioners.   ZeroJunk I think you are right and there should be a threaded hole, plus recess for the parts.  It would seem that my next job will be repairing my Dremmel in preparation for a spot of casing modifications!

[Al_Smith]

Now I would tend to think that greasing an expossed gear be it nylon or any material would cause it to collect bits of saw dust .That can't be good .

Even though the entire gear train is under a cover tiny bits of wood fiber get sucket under the cover .It's amazing just how much in fact and in a short time .

[Andy171361]

 

 

Well that's a good point Al but, paradoxically, if I have succeeded in eliminating the flow of oil through the centre of the worm gear then the teeth of the worm and spur gears will now be unlubricated.  I never saw that coming!  Anyway the good book says use some Stihl multipurpose grease on the teeth, so I did.  Mind you, after reading your comment and looking at the photo again I realise I could wipe away a lot of the excess grease and tidy things up a bit.  I intend to get the side casing off again anyway to see if I have cured the original oil leak, so I will clean the gears up then and look for signs of saw dust in the teeth.  Thanks for your help.  Andy

[Al_Smith]

 :D Well ya got me on that one .It seems I never read the directions although I have tons of literature .I'd have never thought they recommended  grease .

I've pulled the cover before and it's just a big glob of congealed wood fibers and oil .It course it took years to get that way .