Bar oil in crankcase?! Stihl Contra/Lightning

[Dasser82]

Hey all,

Had a bit of time to tinker with my new to me Contra today.

Pulled over with fresh mix a few times to see what happens, pulled plug and it's for sure getting fuel - great!

Pull few more times, check again and see bar oil on plug. Pull over with plug out and sure enough some more spurts out. Turn saw over and a trickle of oil comes out top of cylinder!

From what I've been trying to research sounds like it's a crank seal gone bad? This saw sat for 15+ years with fuel and bar oil in it. More than enough time to eat away an old seal is my guess.

Before I start in that direction is it worth doing a pressure test?

Any help/advice appreciated!

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[Spladle160]

any chance someone put oil down the cylinder to store it or fake compression?

 

[beaglebriar]

Hey all,

Had a bit of time to tinker with my new to me Contra today.

Pulled over with fresh mix a few times to see what happens, pulled plug and it's for sure getting fuel - great!

Pull few more times, check again and see bar oil on plug. Pull over with plug out and sure enough some more spurts out. Turn saw over and a trickle of oil comes out top of cylinder!

From what I've been trying to research sounds like it's a crank seal gone bad? This saw sat for 15+ years with fuel and bar oil in it. More than enough time to eat away an old seal is my guess.

Before I start in that direction is it worth doing a pressure test?

Any help/advice appreciated!

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A proper leak down test will tell the tale. She's prolly gonna need to be split, case gasket is likely leaking.

 

[dall]

A proper leak down test will tell the tale. She's prolly gonna need to be split, case gasket is likely leaking.

and if they do run they work good to get bugs away from the smoke

 

[jacob j.]

The only connection between the oil tank and the crankcase on a Contra is the pulse hose. The pulse hose delivers impulse from the engine
behind the oil pump diaphragm. So if you have bar oil getting into the crankcase, then you likely need to replace the oil pump diaphragm.

 

[Dasser82]

Thanks all!

Yes, most likely going to do some type of restoration on this saw. Replace what's needed, clean, etc. Won't worry about the paint for now as I like her work clothes!

Jacob - much appreciated. I found a service manual too and probably missed where it mentions how it gets impulse. Those photos help a lot.

I'll get it apart and see what needs replacing. No idea when she last ran but I should mention it has great spark and plug looked excellent with good colour before I started.

P.S. I thought my 064 was a good tug to get started without decomp...this thing is on a different level!

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[Spladle160]

If it were me and I split it there is no way I wouldn't get it powder coated unless it was a museum quality piece.

 

[Dasser82]

That's a good point Spladle160, and I think I might get into this a bit more than I thought initially...possibly a full resto. Such an iconic saw.

I've decided to shelve it for now and make it a nice winter project like I did my 064. Too hot to work in shop right now anyways, and I've got lots of eother projects atm (not to mention kiddos to chase around!)

In the meantime I'll continue to glean any and all info i can find.

I will try to document it all as I go!




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[beaglebriar]

The only connection between the oil tank and the crankcase on a Contra is the pulse hose. The pulse hose delivers impulse from the engine
behind the oil pump diaphragm. So if you have bar oil getting into the crankcase, then you likely need to replace the oil pump diaphragm.

Good info JJ. I honestly haven't ever laid hands on a Contra or any of those nice 100+cc Macs you guys have. Those big old saws were not common here.

 

[jacob j.]

Good info JJ. I honestly haven't ever laid hands on a Contra or any of those nice 100+cc Macs you guys have. Those big old saws were not common here.

This is big saw country for sure. When I was in high school (late 80's/early 90's), a rough condition 090 was a $50 saw, and a "pristine" 090 was a $150-200 saw. You couldn't give away big Macs. It was not uncommon
to see 70/80/120cc Macs in dumpsters. I fished a 7-10 Automatic out of the dumpster behind the local NAPA when I was 17 because I thought I could tinker with it and get it running. I ended up trading it for a Husky
42 with a 16" bar because that was a more useful saw to a kid just doing landscaping and tree trimming.

 

[Dasser82]

This is big saw country for sure. When I was in high school (late 80's/early 90's), a rough condition 090 was a $50 saw, and a "pristine" 090 was a $150-200 saw. You couldn't give away big Macs. It was not uncommon
to see 70/80/120cc Macs in dumpsters. I fished a 7-10 Automatic out of the dumpster behind the local NAPA when I was 17 because I thought I could tinker with it and get it running. I ended up trading it for a Husky
42 with a 16" bar because that was a more useful saw to a kid just doing landscaping and tree trimming.

Wow that's crazy Jacob - goes to show how prices can vary from West Coast region to where we are. Rarely do I see 090's for sale within 300 mile radius of me, and when they do they're always listed for at least $1500 in any condition.

Actually one just popped up this morning for $1500 with 36" bar and 2 chains (ripping and skip). No mention of it even running.

A Mac 797 super also up 30 mins from me in great shape, but he's holding out for best offer. Judging from his description I. Ant think he'd take any less than $1000. But it does run.

Can't imagine finding saws of this size in dumpster!

These are my 2 "beasts!". 064 beside Contra/Lightning.

Chad

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