Probably a way to save money on labeling. People who buy it aren’t looking for Jaso or API certified
McCulloch Chain Saws
- Thread starter Bruce Hopf
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Item 9 is the governor arm assembly, also known as an air vane governor. This illustration is from the 1-85 but the 1-75 will be the same. Air vane governors were used before electronic ignitions with rev limiters were commonly available as a way to prevent the engine from overspeeding. You can adjust the arm that engages the throttle lever (item 12) to raise or lower the RPM the engine will achieve before the air vane governor kicks in.
Mark
Mark
I was thinking the same thing,save money on the labeling.Yeah,the Tech 2 cycle oil was most likely designed for guys who aren't "professionals".I'm far from being a professional timber cutter,but I'm not the average weekender who cuts a few cord a yr.(if that) for his fireplace.I cut & hauled 23 cords of wood myself & my son helped me with another 4 cords.On average I put in about 25+/yr.I'd like to get some more in this fall,but the weather hasn't been cooperating thus far.
Thanks Mark! Apparently the governor vane is broken off on my 1-75.I'm assuming that the governor vane from a 1-70 will fit?
This is off my 1-70. I removed it to get rid of one of the variables to get it running. If it’s broke then it’s likely holding the the throttle closed. 
They are different part numbers, 1-70 is 51704 and 1-75 is 55966. I don't know if they would be interchangeable.
Mark
Mark
Thanks Mark. just trying to give a visual.
It’s a PITA but if you loosen the little set screw you can disable the Governor to at least get the saw running then worry about adjustment later on.
It’s a PITA but if you loosen the little set screw you can disable the Governor to at least get the saw running then worry about adjustment later on.
Thanks Mark & Goin Wheelin.I'll have to take a much closer look at the 1-75 tomorrow.I'll be putting the points & condenser back in & hopefully get spark.Then I'll pull the carb off the 1-70 for a rebuild on Thurs.or Fri.Going crazy here trying to get the basement loaded up with wood for the winter,it holds around 10 cords.Hardly any time for saw work at the moment,but it's supposed to start raining & chill down on Thurs.,so plenty of time coming for saw work.
I called Bob J.today to order the air vane governor & it seems that you gave me the wrong part # Mark.You gave me part # 55966 which is the spring,the part # for the governor is 55958.Regardless,Bob didn't have any in stock.I did find one on Feebay & have sent an offer.
2broke2ride
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I had a little while after dinner tonight to mess with the 550. Swapped in a rebuilt Tillotson HL63 from a 250 and she's a runner. No tuning here so she may be a bit lean but I will get a bar and chain on her and do a little test and tune maybe this weekend [emoji3] pretty stoked for this saw.
I will still tear it down at least partway for a thorough cleaning and replace crank seals, fuel lines, and any needed gaskets.
Oh, BTW, this is one of 3 carbs that where tried on my Super 250 that all acted the same. So that rules out the carb. I am thinking a fuel line or filter issue because I don't really think I could have missed that big of an air leak while doing a full rebuild with all new gaskets and seals, piston and rings, but we will see I suppose.
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I will still tear it down at least partway for a thorough cleaning and replace crank seals, fuel lines, and any needed gaskets.
Oh, BTW, this is one of 3 carbs that where tried on my Super 250 that all acted the same. So that rules out the carb. I am thinking a fuel line or filter issue because I don't really think I could have missed that big of an air leak while doing a full rebuild with all new gaskets and seals, piston and rings, but we will see I suppose.
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Sounds good Kevin!
I did some checking on the air vane governor after I put in an offer on Feebay.I called Discount Marine & they had one for $16.Meanwhile the seller on Feebay countered my offer of $7.50 with $8.50,so I accepted the counter.The one on Feebay is also a NOS.I don't think the governor was broken,I think it was taken off deliberately to get more RPMs out of the saw,but isn't that kinda dangerous for the saw's engine?I should pull the muffler & have a look at the P&C,I usually do this,but haven't yet.
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The governor is not in play when cutting and if it's tuned right, you won't over rev it free reving either. And you really shouldn't be free reving that much anyway lol. They eliminated it on later model saws without really changing anything else so the engineers must have figured out it wasn't really needed.
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What is a good way to clean the mac air filters? I have a 66774 air filter that when installed kills the 10 10 Aa saw. First time this saw went to the woods with me, it ran good for a bit. My 700 was being a bugger also, it ran great until I shut it off and it would not re start. Drained the gas and it started first pull, 3/4 filled it and it would not start again. Drained the gas and it started 2nd pull. After checking the gas filter it was not sitting in the bottom of the tank and the gas had some moisture in it. Next time will be better! Oh, and I have a bear den in the area I cut wood and hunt but that story is for another time.
The 550 is pretty cool. Nice job.
I use compressed air to clean the filters off.
I use compressed air to clean the filters off.
Depending on the frocking I'll wash them in warm soapy water and set them in the sun to dry. Dawn works good.
I just use compressed air, if the flocking comes off it is time to replace the air filter anyway. On some of the hard to find air filters I will gently brush them off, the shop vac with the brush attachment will work O.K. if the filter is not too wet from spit back fuel.
Mark
Thanks for that info Kevin,much appreciated.I have plans on getting the points back in today,so I can give it a shot (if it has spark) on getting it fired up without any fears of engine damage.
Funny how the post just came up about clean/dirty air filters.The air filters on the 1-70 wasn't too awfully bad,but the filter on the 1-75 was caked with dirt & oil.I haven't tried cleaning it yet,but I also use Dawn dish detergent & it works great.I have a feeling that I'll be buying a new filter for the latter.
I used the dish soap method and it looks pretty good. I can see how gas would better dissolve the baked in oil.
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