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McCulloch Chain Saws

edju1958

edju1958

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I did a little playing with the 5-10 today.I've got about 125-130 psi on the compression,a bit on the low end,but still operable.I tried yet another plug & noticed that the plug I took out was wet,so it wasn't firing.I put a shot of fuel into the cylinder & it fired,then I gave a shot of fuel in the carb & it fired again.I think I had a combination of a bad plug & it was flooded.Now I've got to figure out the switch.I saw on either an old 2-10 or 10-10 where someone had drilled a hole in the flywheel side shroud & put a toggle switch in it because the switch/DSP didn't work anymore.IMO putting the 2 together wasn't a good idea.I'm waiting on a new fuel line from Bob J,I've found that the aftermarket ones on Feebay aren't very good,they constantly leak..
 
heimannm

heimannm

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I would much rather start a 550 with no compression release than try and start a fresh SP80/81 or PM850 without using the compression release. Even if you could put the bigger starter handle and larger diameter rope on the 82 cc 10 Series, the flywheel/starter housing may not be up to the task. I have several broken housings and starters in the attic from folk who ignored the compression release.

Mark
 
heimannm

heimannm

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One of my local chain saw buddies stopped by this morning to get some parts, offered to let me help with a project this afternoon. He was taking down a large soft maple tree and thought I might like to give the SP125 a stretch. I took two, my current work saw in order to run the fuel out of it, and the recently assembled junk yard dog to give it a real test. The JYD is not as strong as my regular work saw but it is still pretty good and will become my first option when I need a long bar. The work saw will get cleaned up and go on display in the museum for now.

The work saw, now bound for the museum. (photo was taken in May...)

20200604_143109.jpg

The JYD, I'll run it till it drops, should be a while no more often than I need it. The muffler came loose on the second tank of fuel today so I installed a longer cap screw and drilled the heads of the screws so I could safety wire them when I got home.

20201215_165544.jpg

Mark
 
edju1958

edju1958

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I would much rather start a 550 with no compression release than try and start a fresh SP80/81 or PM850 without using the compression release. Even if you could put the bigger starter handle and larger diameter rope on the 82 cc 10 Series, the flywheel/starter housing may not be up to the task. I have several broken housings and starters in the attic from folk who ignored the compression release.

Mark
I know what it's like to try to start my 7-10 without a DSP,,now add another 12ccs to the mix & you might be looking at shoulder surgery down the road.When those saws kick back they'll take your hand off as well.
 
Jethro 2t sniffer

Jethro 2t sniffer

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Yes I've accidentally tried pulling my sp81 with decomp off and holy cow it's quite the shock to the shoulder. However, I'd be more concerned in how long the recoil assembly could take it.

Yeah it will bust it or the rope. Got me the other day too. Yanked straight through my fingers ouch...decomp you dumb ass hahaha
 
edju1958

edju1958

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Well back to the 5-10,Lol.I put 2 more different plugs in the saw & was getting erratic spark,kinda yellowish looking,which to me meant it was weak.I got the switch working (I think).I took the side cover off & went to reattach the switch wire to tyhe coil & found all kinds of oily sawdust packed around the spade,that could've been what was causing it to ground out.I also checked the switch wire to make sure there were no spots where it might've worn through.I like using brake cleaner on electrical stuff like switches.It cleans them & doesn't leave a residue.Anyhow,with the weak spark I figured it was time to have a lookl at the points,so pulled the flywheel & pulled the points out (I can see them better that way),the points were so black that I don't know how the saw was firing at all.I've got them cleaned up now & they'll go back in tomorrow.I'll get that dang saw running yet,Lol.
 
matt_lamb_160

matt_lamb_160

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Can anyone assist with IDing this McCulloch? It is a front tank style chainsaw like a 250. It has a full wrap handle and a round muffler, but different to the super 250 one. Numbers on the underside read 62481 and A5449. The carb appears to have been messed with (swapped), but it is a flat back with a primer.
 
matt_lamb_160

matt_lamb_160

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Thanks. Interestingly it came with another saw stamped as a 450. There were filter covers for an s550 and a 450 on the saws. What I have found on the numbers I posted, it is a 250 or a Super 250 like you say.
 
Brushswamper523

Brushswamper523

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Alright fellas I know you all want an update on the PM850. Finally got the carb kit and fuel line I ordered. Rebuilt the carb which was an adventure in its own with screen and circlip behind the welch plug but got it with some help from youtube. Now started painting. Should be assembling this weekend and will take a starting video. I am going to attempt to start it without the decompression switch but once it starts I will order that. Fingers crossed I won't mess up the starter shaft since that is how I got the saw with that broken already. All in all it has been a good one so far looking forward to having it all done with wood cutting for me right around the corner. Cheers.
 
Jethro 2t sniffer

Jethro 2t sniffer

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Alright fellas I know you all want an update on the PM850. Finally got the carb kit and fuel line I ordered. Rebuilt the carb which was an adventure in its own with screen and circlip behind the welch plug but got it with some help from youtube. Now started painting. Should be assembling this weekend and will take a starting video. I am going to attempt to start it without the decompression switch but once it starts I will order that. Fingers crossed I won't mess up the starter shaft since that is how I got the saw with that broken already. All in all it has been a good one so far looking forward to having it all done with wood cutting for me right around the corner. Cheers.

Awesome but your a keen man with no decompression valve
 
Brushswamper523

Brushswamper523

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Awesome but your a keen man with no decompression valve
Yea I should buy one before I start but that would be another 2 weeks at this rate before I can fire it over. I am very anxious about firing it. Who know I will sit on it a minute. I may wait just order one so I don't mess stuff up.
 
PogoInTheWoods

PogoInTheWoods

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It might start without the blocking plug even being in the decomp location..., or at least with it loosened enough to lower the compression similarly to the decomp.., probably around 90 ~ 100psi if I'm not mistaken. Just don't run it long or at high rpm's if it does start and run..., or stick your face in front of the plug! It may at least provide some preliminary gratification (and save some wear and tear on your shoulder and the recoil assembly) until you can get a proper valve to run it for real.
 
matt_lamb_160

matt_lamb_160

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I measured the bore and stroke of the saw I saw trying to ID through the exhaust port (and using key features of the piston for stroke) and it seems to be a std. 250 with a 1.375" stroke and 2.125" bore. Dressed up as a Super 550 with full wrap bar and s550 filter cover, the guy I bought it from is a good guy and didn't know so no issues there, just thought I would share the ID. Bit disappointing, but it can join my collection of 250s (starting to lose count!). Seems to have good compression and has spark.
 
Jethro 2t sniffer

Jethro 2t sniffer

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It might start without the blocking plug even being in the decomp location..., or at least with it loosened enough to lower the compression similarly to the decomp.., probably around 90 ~ 100psi if I'm not mistaken. Just don't run it long or at high rpm's if it does start and run..., or stick your face in front of the plug! It may at least provide some preliminary gratification (and save some wear and tear on your shoulder and the recoil assembly) until you can get a proper valve to run it for real.

That's actually not a bad idea. Could even cut a groove up the side of the bolt or cap screw and open it until the groove is open crank it up then tighten it back up so the groove is inside the threads again.

If ya use a hex key with no ball on it and maybe grease on the end it might stay in there while ya get it going for a quick shut of the "valve"
 
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