No.
What causes dying on sustained load?
- Thread starter Canyon Angler
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Canyon Angler
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Well, I tried a new fuel filter and that didn't fix it, so I ordered another carb kit.
Since this saw seems to be giving me more and more trouble over the years, I'll also test for air leaks. I'm new to testing for air leaks, although I did buy the tool kit for testing for air leaks a year or two ago, but didn't use it yet. Is there anything special I need to do on a saw that has a reed box when testing for air leaks?
Since this saw seems to be giving me more and more trouble over the years, I'll also test for air leaks. I'm new to testing for air leaks, although I did buy the tool kit for testing for air leaks a year or two ago, but didn't use it yet. Is there anything special I need to do on a saw that has a reed box when testing for air leaks?
Testing for air leaks is quite simple, one just needs to block all openings of the cylinder to prevent air entrance no matter if its piston ported or reed valve induction. The three usual openings are the intake under the carb, exhaust port behind the muffler and sometimes an impulse line/nipple that is external. Leave the sparkplug in and plug the decomp if the cylinder has one. The decomps will leak even if new and leak even more if its been used. Just to add, one of the openings will need to be used to pull vac through, use the one that is most convenient to your setup.
Canyon Angler
Addicted to ArboristSite
What a great succinct and simple detailed reply, thank you very much.
Just to follow up, I guess if all three openings (intake, exhaust and impulse -- I have no decomp on this saw) are either blocked off or connected to vacuum, it doesn't matter where the piston is -- TDC, BDC or anywhere in-between, right?
And, if I find no air leak that way, I guess I should then check the impulse line for a leak? I guess there's no way to check whether the carb-to-cylinder gasket is leaking air...?
I suspect these are dumb questions but that never stopped me before.
One of these days I need to assemble the complete FarmerTec/Huztl 361 kit I bought, maybe after that I would have a clue.
You can block off the intake side at the carb to flange connection but not forward of that so testing the actual gasket between the carb and its mounting flange is rather difficult. Actual physical examination will tell if the gasket is compromised in some way. It does not matter where the piston is located in the cylinder, air will leak around the piston and rings as they are not totally air tight. If a saw has an external impulse line I will leave the line on and pull vac through it, in that way the line gets its test at the same time.
Just couple hints about this from experience:
I have not read all of this thread and this might already be suggested.
Something that is quite often overlooked easily such as you describe with a chainsaw is overheating of the piston/block. The piston's skirt is swelling into the cylinder and eating itself due to heat. At first you can usually take the saw out of the cut, piss rev for awhile get a ok rev and then back into the cut and same thing again. The piston is eating due to swelling into the jug, friction increasing producing more heat and the piston is eating itself and it appears to be fuel related or chain/clutch bogging in a sustained cut.
Very easy to ruin a saw FAST when this is happening because it leads you to think that the saw is starving for fuel, chain, clutch is binding/pinching because the rpms will start decreasing when in a full bar loaded cut for longer than 30 seconds and removing the load and revving the saw may get it back up to throttle good. You also will not ever notice such in light unloaded cuts of less than 20 seconds to 1 minute. cuts and trimming. I've seen them eventually just seize up, cannot pull the recoil and it pulls with friction and may start and run again after a cool down.
I use a 3M IR therometer. You can find good reliable IR therometers for around $25 now days.
A tach will show that the rpms are not being exceeded during these type cuts and loads.
Here is some info about such at this link on this site: read all but pay attention to #6 and #10 post
https://www.arboristsite.com/community/threads/handheld-tach.342660/.
I have not read all of this thread and this might already be suggested.
Something that is quite often overlooked easily such as you describe with a chainsaw is overheating of the piston/block. The piston's skirt is swelling into the cylinder and eating itself due to heat. At first you can usually take the saw out of the cut, piss rev for awhile get a ok rev and then back into the cut and same thing again. The piston is eating due to swelling into the jug, friction increasing producing more heat and the piston is eating itself and it appears to be fuel related or chain/clutch bogging in a sustained cut.
Very easy to ruin a saw FAST when this is happening because it leads you to think that the saw is starving for fuel, chain, clutch is binding/pinching because the rpms will start decreasing when in a full bar loaded cut for longer than 30 seconds and removing the load and revving the saw may get it back up to throttle good. You also will not ever notice such in light unloaded cuts of less than 20 seconds to 1 minute. cuts and trimming. I've seen them eventually just seize up, cannot pull the recoil and it pulls with friction and may start and run again after a cool down.
I use a 3M IR therometer. You can find good reliable IR therometers for around $25 now days.
A tach will show that the rpms are not being exceeded during these type cuts and loads.
Here is some info about such at this link on this site: read all but pay attention to #6 and #10 post
https://www.arboristsite.com/community/threads/handheld-tach.342660/.
What no Strawberry alarm clock ?
Window pain.
