I've had old saws that wont start with bad crank seals (leaking crankcase pressure), that may at least pop off, and have also had some that will still run,but like crap. The junk saws I've fixed I'd say 90% have a bad crank seal/bearings. Overheating clutch is a big culprit of seals going bad on that side too. Love your videos!
Most of those compression gauges give too low readings for small engines because the check valve is too far away from the cylinder being measured and the volume of the connecting hose is significant in relation to the volume of the combustion chamber.
Fantastic advice, I just recently picked up a Stihl HT75 pole saw. It just doesn't run, I was able to make it pop off and idle a little but it stalled and hasn't run after that. What it is doing is pouring gas out of the muffler after pulling on the rope for a while. I pulled the muffler and checked the piston, rings and the port and muffler for carbon buildup. The piston and rings are like new. The port and muffler are clean. I checked for spark and if you rill the engine over slowly there is none you have to give the rope a good pull. that being said the spark will jump a 1/2" gap. I'm to the point now that I am going to pull the carb off and check the diaphragm. I think it might be crispy. Since I just moved from one house to another all my tools are packed away. I need to check the compression but it feels good. I'm not sure this will work on a 2 stroke but, when checking the compression hold the throttle open to allow more air into the cylinder. love the channel. You explain everything so well. I have a few of the older Mcculloch and Homelite saws, I like the presafety saws so its' no chain brake, anti kick back bars/ chains and it's loud exhaust for me. Thanks for the advise you give.
I have a question, I am replacing the piston and cylinder on one of my old Super XLAOs. What oil gasoline mix do you recommend during break in? When these saws were new Homelite recommended a 32 to 1 mix using Homelite oil and 16 to 1 using anyone else's. With the advancement in modern lubricants what mix would you use for normal saw use? I know the more oil in the gas mix leads to more carbon and possible piston and cylinder scratching, as we know carbon is the first stage of a diamond and very hard, an unwelcome deposit in a combustion chamber. I really enjoy and appreciate your videos, thanks again.
Sad day, my cousin borrowed the 925 you worked on for me, ran the piss out of it on really hot day last week and called me saying it heat stalled twice on him... I'm a little hot myself right now but my fault for letting him borrow it.
I have a shindiawa C35 brush cutter that will start to bogg down when I tip the machine left or right and up and down. I suspect leaking bearing seals so I have them on order. I’m also running a good mix at 25:1 which is what the manual calls for and oil drips from the muffler so I’m guessing leaking seals are fouling up the mixture and causing a the oil to go unburned. My pressure and vacuum test indicates a very very slow leak which probably gets worse when it gets warmed up. Carb tested good and no leaks from the tank or lines. The tip test makes me lean towards the seals. Please correct me if I’m wrong.
Your completely wrong. Air/fuel is injected into the cylinder from crankcase under 6-8 psi, if you have low crankcase pressure, there is less VOLUME being compressed in the cylinder, low crankcase pressure equals low cylinder pressure, the cylinder on a two stroke doesn't draw any air, all the air that goes into the cylinder is injected into the cylinder under pressure, if the crankcase can't build pressure, the cylinder is only compressing atmospheric pressure. Yesterday I had power mac 6 with only 55 psi cylinder compression, found that the oiler had bad gasket, causing the crankcase to vent, replaced the gasket, and cylinder compression went up to 99 psi.
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Right with you with the cheap compression gauges, learned that the hard way.
Very helpful information.
I've had old saws that wont start with bad crank seals (leaking crankcase pressure), that may at least pop off, and have also had some that will still run,but like crap. The junk saws I've fixed I'd say 90% have a bad crank seal/bearings. Overheating clutch is a big culprit of seals going bad on that side too. Love your videos!
Most of those compression gauges give too low readings for small engines because the check valve is too far away from the cylinder being measured and the volume of the connecting hose is significant in relation to the volume of the combustion chamber.
good info,thanks
Appreciate the education !!, been around saws most of my life , just never worked on one , , mostly firewood cutting,
You should do a video on how you check your crank case
Fantastic advice, I just recently picked up a Stihl HT75 pole saw. It just doesn't run, I was able to make it pop off and idle a little but it stalled and hasn't run after that. What it is doing is pouring gas out of the muffler after pulling on the rope for a while. I pulled the muffler and checked the piston, rings and the port and muffler for carbon buildup. The piston and rings are like new. The port and muffler are clean. I checked for spark and if you rill the engine over slowly there is none you have to give the rope a good pull. that being said the spark will jump a 1/2" gap. I'm to the point now that I am going to pull the carb off and check the diaphragm. I think it might be crispy. Since I just moved from one house to another all my tools are packed away. I need to check the compression but it feels good.
I'm not sure this will work on a 2 stroke but, when checking the compression hold the throttle open to allow more air into the cylinder.
love the channel. You explain everything so well. I have a few of the older Mcculloch and Homelite saws, I like the presafety saws so its' no chain brake, anti kick back bars/ chains and it's loud exhaust for me. Thanks for the advise you give.
I have a question, I am replacing the piston and cylinder on one of my old Super XLAOs. What oil gasoline mix do you recommend during break in? When these saws were new Homelite recommended a 32 to 1 mix using Homelite oil and 16 to 1 using anyone else's. With the advancement in modern lubricants what mix would you use for normal saw use? I know the more oil in the gas mix leads to more carbon and possible piston and cylinder scratching, as we know carbon is the first stage of a diamond and very hard, an unwelcome deposit in a combustion chamber. I really enjoy and appreciate your videos, thanks again.
Although it is unlikely that I'll ever work on a XL or EZ or a Mac Superpro this is still great content for the saw hobbyists, subbed
The movie rundown Boom Shakalaka.👍👍👍👍👍👍👍
Great explanation sir thank u hope all are well.
love the videos! you're one of my sensei's!
Sad day, my cousin borrowed the 925 you worked on for me, ran the piss out of it on really hot day last week and called me saying it heat stalled twice on him... I'm a little hot myself right now but my fault for letting him borrow it.
Was the chain dull? Was it Black? 😡
@@613kc it was razor sharp when I loaned it, haven't gotten it back yet.
@@jeremiahjohnson5278 Does it have Bumper Spikes?
@@613kc of course.
I have a shindiawa C35 brush cutter that will start to bogg down when I tip the machine left or right and up and down. I suspect leaking bearing seals so I have them on order. I’m also running a good mix at 25:1 which is what the manual calls for and oil drips from the muffler so I’m guessing leaking seals are fouling up the mixture and causing a the oil to go unburned. My pressure and vacuum test indicates a very very slow leak which probably gets worse when it gets warmed up. Carb tested good and no leaks from the tank or lines. The tip test makes me lean towards the seals. Please correct me if I’m wrong.
Your completely wrong. Air/fuel is injected into the cylinder from crankcase under 6-8 psi, if you have low crankcase pressure, there is less VOLUME being compressed in the cylinder, low crankcase pressure equals low cylinder pressure, the cylinder on a two stroke doesn't draw any air, all the air that goes into the cylinder is injected into the cylinder under pressure, if the crankcase can't build pressure, the cylinder is only compressing atmospheric pressure. Yesterday I had power mac 6 with only 55 psi cylinder compression, found that the oiler had bad gasket, causing the crankcase to vent, replaced the gasket, and cylinder compression went up to 99 psi.