McCulloch Chain Saws

[2broke2ride]

I didnt get that impression at all. I just wanted it known that I cast no blame. In fact, quite the opposite, I am grateful that Mark is doing what he is doing.

 

[edju1958]

Sometimes you gotta think outside the box.You've all pointed to the fact that this saw has the RIGHT piston in it.Suppose you put the WRONG piston in it & try it?I don't know if that can be done,or what the results would be.Kevin put the same piston in the saw as what was in it when he got it.What if the original owner put the wrong piston in & created this problem (I'm hoping Mark wasn't the original owner Lol),meaning that the piston that's in the saw isn't the right one?Maybe my "logic" isn't logical?
Ed

 

[PogoInTheWoods]

See post # 31931

 

[edju1958]

I need a little help on my 380A.The auto oiler isn't working & it doesn't have a manual oiler.I've been told this is an impulse oiler.The oil tank sits behind the fuel tank on this saw.
Ed

 

[heimannm]

The 380 should have a manual oiler, button on the left of the rear handle.

Mark

 

[edju1958]

The 380 should have a manual oiler, button on the left of the rear handle.

Mark

It doesn't have the manual oiler on it,it's an auto only oiler.Tim saw this on Mon.,he can verify it.
Ed

 

[vinnywv]

Mark, any new news on the 7-10? You said you were giving up, i was just wondering if you were or just putting it aside for now.

 

[vinnywv]

Aaron rybicki, i see a sp70 with your name on it?? If i hadnt just got that cp125 id be all over that one. Good luck on it.

 

[heimannm]

I have been given an assignment that will take me to Seattle for two weeks so I am going to let it set while I'm gone. If anyone comes up with a good idea I might give it another try.

Mark

 

[PogoInTheWoods]

I'd say we're basically down to the cylinder at this point. Can't help but think there would be different porting for the 85240/69412 closed skirt style piston than for the half-skirt style 85239/69020. I ran across a similar discussion elsewhere about the interchangeability of the pistons and did see a post indicating the 85239 was an acceptable service upgrade for any of the 70cc saws..., presumably including those with the closed skirt pistons. Whether or not that was fact or opinion wasn't specifically established and there was no mention of possible considerations for the various part numbers given to the different crankcase assemblies -- which of course include the cylinders without individual part numbers for the most part.

We need pics of the associated cylinders for the two different pistons as the easiest way to possibly reach a conclusion about the porting unless someone can otherwise illuminate the issue by providing definitive documentation on the matter. And as someone mentioned earlier, maybe there's been some grinding on this particular cylinder that didn't exactly yield the intended results? Seems like that would have been fairly obvious during the teardowns and rebuilds unless it was very high quality work.

And without re-reading everything again, the replacement piston is an OEM piston and not a Little Red Barn knock-off, correct? And I keep thinking the compression is too low as I believe someone else has also already mentioned. Not much need to include a compression release feature on a saw that only blows 130 with a new piston and fresh rings, tho. I also can't recall if this cylinder has a cast iron sleeve or chrome bore...

So does anyone have an early 4-10 ~ 6-10 in a box somewhere longing for a photo op? And maybe a burned up 7-10 / PM700 cousin also needing some camera time to compare innards with?

 

[peter92]

Had a good score last night , picked this up , just cleaned the filter thats why it and the top isnt on the saw
SP 125 , hasnt ran in 30 years , took a bit to keep it running but runs really well now and got a NOS bar brand new and aslightly use one plus the one on the saw

Peter

 

[edju1958]

Mark,if you go to page 1533 near the top there's a pic of my 380A that I put on here back in Jan.You can clearly see that there is no manual oiler button on the saw,only a rubber plug where it should be.This saw was not made in the U.S.
Ed

 

[joeymt33]

I have been given an assignment that will take me to Seattle for two weeks so I am going to let it set while I'm gone. If anyone comes up with a good idea I might give it another try.

Mark

I’m sorry if I missed it but have you guys measured the stroke? 130psi seems a little low for a new piston and rings.

 

[2broke2ride]

I do not believe it's been checked, I have sort of theorized a bent rod for a while now due to the physical damage i found on the original piston and no real explanation for it.

 

[2broke2ride]

I'd say we're basically down to the cylinder at this point. Can't help but think there would be different porting for the 85240/69412 closed skirt style piston than for the half-skirt style 85239/69020. I ran across a similar discussion elsewhere about the interchangeability of the pistons and did see a post indicating the 85239 was an acceptable service upgrade for any of the 70cc saws..., presumably including those with the closed skirt pistons. Whether or not that was fact or opinion wasn't specifically established and there was no mention of possible considerations for the various part numbers given to the different crankcase assemblies -- which of course include the cylinders without individual part numbers for the most part.

We need pics of the associated cylinders for the two different pistons as the easiest way to possibly reach a conclusion about the porting unless someone can otherwise illuminate the issue by providing definitive documentation on the matter. And as someone mentioned earlier, maybe there's been some grinding on this particular cylinder that didn't exactly yield the intended results? Seems like that would have been fairly obvious during the teardowns and rebuilds unless it was very high quality work.

And without re-reading everything again, the replacement piston is an OEM piston and not a Little Red Barn knock-off, correct? And I keep thinking the compression is too low as I believe someone else has also already mentioned. Not much need to include a compression release feature on a saw that only blows 130 with a new piston and fresh rings, tho. I also can't recall if this cylinder has a cast iron sleeve or chrome bore...

So does anyone have an early 4-10 ~ 6-10 in a box somewhere longing for a photo op? And maybe a burned up 7-10 / PM700 cousin also needing some camera time to compare innards with?

It was an NOS piston from Mark.

 

[joeymt33]

I do not believe it's been checked, I have sort of theorized a bent rod for a while now due to the physical damage i found on the original piston and no real explanation for it.

I guess all the 10 series have the same stroke anyway if I remember correctly? Even if they are 70cc or 54cc

 

[edju1958]

Trying to figure out how it can get a bent connecting rod.It'd have to be going like a bat out of hell at high rpm's & then suddenly lock up in an instant.It seems that there'd be other damage elsewhere too,almost to the point of the engine being trashed.Pls enlighten me if you will.
Ed

 

[PogoInTheWoods]

Could have happened outside of the saw somehow. Unlikely, but could also have happened if someone used a steel piston stop to lock the crank to remove the clutch (or flywheel nut for that matter) in the wrong direction with excessive force or an impact. Would probably have also trashed the piston if it weren't already..., which could have been the reason for tearing the saw down in the first place. Neither are very likely, but both are possible.

And that chunk out of the piston looks like it may be the exhaust side. Maybe someone shoved something through the exhaust port to use as a piston stop or for some other reason and soon realized it wasn't a very good idea?

We need cylinder pics for each type of piston.

 

[edju1958]

If the rod is bent,that'd explain a timing issue,but could it cause low compression?
Ed

 

[rocketnorton]

yep.
wrong rod?