McCulloch Chain Saws

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Check all your connections,especially the ground.Those Atom chips have been around for about 20 yrs.,maybe longer.I wonder if it's possible that after all that time it may be starting to break down?You could get a new chip for about $20 & see if that makes a difference.
Ed
 
I had a 610 torn down last summer (2 actually) & ya can't put a gasket on the oil tank,only a very thin layer of silicone sealant.Is that the best way to replace seals on the 600 series saws,by tearing them right down?After doing a couple saws they're not really that bad,just labor intensive.
Ed
you can probably dig them out like any other but you will have to remove the handle, starter, gas tank, flywheel, that metal plate and clutch. Pay attention to how the coils wires are routed over the oil pump. Dont loose the little cushion on the fuel line between the gas tank and carburetor box. You may need a hand impact driver and blue thread locker. All three of my 600's had mucked up spark arrestors.
 
I don't think it matters if the chip was "designed" for a go cart or not.They used Mac engines extensively in go carts,so if the engine came out of a saw & was put in a go cart does that mean the chip has to change?I think not.I'd say to try a different chip for $15 or $20 & see if it makes a difference.If there's no difference you're not out that much money,& you have a chip for another possible application on another saw if the need arises.
Ed
 
Yeah maybe I'm over thinking things.

However, kart engines were typically a bit different usually with better porting, different air intake/carb configurations, and better exhaust. And of course Yamaha didn't make saws, so kart engines from them were likely derived from a motorcycle engine.
 
I'd pull the flywheel to see of someone may have messed with the timing by changing the key way orientation..., or not. Some older modules have been said to require moving the flywheel to accommodate inherent timing problems while the newer ones do not. And if you go with a new module, these are the popular ones these days:
Pretty much all the same chip and have dual leads for easy polarity reversal if necessary. 10 ~ 12 bux.
-Rotary “Nova II” module; P/N 8786
-Stens “MegaFire II” module; P/N 440-465
-Oregon “Universal Ignition Module”; P/N 33-053 (or 147-020)
 
Not over thinking it's a fair thought if it was made for a hi performance kart it may have an advance curve to go with the way that engine is ported and likes to run. You could test it with a light and see what happens over the rev range. If it cuts well why change it perhaps it's a good thing.

Modern 2 stroke dirt bikes use a throttle sensor in the carb and change the ignition curve to suit what's happening at the time. But even right back to the first cdi bikes the ignition was being played with and why not there's power to be had.

Maybe it runs a little flat lower down compared to a point saw but comes alive higher up.

I still feel my 7-10 saws have a tad more zing to them over the pm700 due to the ignition. The 700 was still pretty early on in electronic ignition tech.

Vinny swears by the chips and he is a man who cuts wood and uses them not just shelf saws that run. Perhaps the novas have a curve built in
 
Thanks jethro, i do like them. I use the cheapest ones on ebay. I have only had one fail. They are very easy to wire in. The hardest part is picking out the best place to mount them. Ive got one in both cp125, one sp81, a 10-10, 55 gear drive, homy xp1000, stihl 015,....i think thats it..lol. its hard to argue with success. They just work. The biggest change i have noticed was the sp81. It really made a difference in that saw. For the good. I had to adjust the carb way back on idle and the response was much quicker. After that it was my go to fix. Some people love points and when they work they work great. Ive got them in all the other old saws with no problems. But if they fail and i say fail not just get dirty, i replace them.
 
NorthEast Tennessee Pre-Season MAC Report

Brian and I got called out for a little pre-season cutting. He did most of the cutting and the hauling. I ran two tanks through my 800 before losing a bar nut (had my parts kit but alas, no spare - have to restock before the season begins). As usual Brian ran multiple MACs - 800, 125 and I believe a 1010.

Red Oak - my 800.
IMG_4569.JPG

Brian feeding his 125 a snack.
IMG_4582.JPG

Brian in the "no saw zone".* We may need to find us a good lawyer.
IMG_4585.JPG

Deere's maiden run off the farm.
IMG_4550.JPG

Ron

*Neither of us got the memo. No incriminating pictures of me and the 800 in the restricted area. Now if I could only find that missing bar nut. Last seen about 18" from the butt end.

This valuable report is provided through the the generous support of MacNuts like you and Blind Squirrel Falling, one of America's greatest imaginary businesses.
 
NorthEast Tennessee Pre-Season MAC Report

Brian and I got called out for a little pre-season cutting. He did most of the cutting and the hauling. I ran two tanks through my 800 before losing a bar nut (had my parts kit but alas, no spare - have to restock before the season begins). As usual Brian ran multiple MACs - 800, 125 and I believe a 1010.

Red Oak - my 800.
View attachment 756610

Brian feeding his 125 a snack.
View attachment 756611

Brian in the "no saw zone".* We may need to find us a good lawyer.
View attachment 756612

Deere's maiden run off the farm.
View attachment 756613

Ron

*Neither of us got the memo. No incriminating pictures of me and the 800 in the restricted area. Now if I could only find that missing bar nut. Last seen about 18" from the butt end.

This valuable report is provided through the the generous support of MacNuts like you and Blind Squirrel Falling, one of America's greatest imaginary businesses.


Ahhh Sunday morning a hot stiff coffee and a report from blind squirrel falling. Yup every thing is right today:) thanks Ron and Brian.

Ps .What thread is your 800 studs? I lost a 7-10 nut and the 800 was wrong thread seemed kinda odd
 

Latest posts

Back
Top