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Post by kevinm1980 on Sept 8, 2021 8:02:46 GMT -5
So have a few xl-76 saws, but one keeps boiling gas, have cleaned it out, it's not running lean has no air leaks but keeps boiling gas, saw runs great and is very strong, I'm wondering if pulling screen of starter might help with air flow?? Have seen several xl-76 saws that did not have screen, any input would be appreciated thx
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Post by tangobravo on Sept 8, 2021 8:37:09 GMT -5
I'd be checking the cylinder cooling fins for any debris build-up. Disassemble as necessary to clear-rear handle off if required. Also check the exhaust port for any carburized deposit blockage, the muffler and baffles/screen for deposits. Check if the muffler is loose or burned out and directing exhaust back toward the engine anywhere.
Heat has to be coming from some source, not getting out, to do this.
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Post by kevinm1980 on Sept 8, 2021 9:25:09 GMT -5
I might pull it apart again but, went through it twice already and its clean as can be, might check for muffler leakage but really haven't notice any signs of that last time I had it appart
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Post by fossil on Sept 8, 2021 9:35:33 GMT -5
So have a few xl-76 saws, but one keeps boiling gas, have cleaned it out, it's not running lean has no air leaks but keeps boiling gas, saw runs great and is very strong, I'm wondering if pulling screen of starter might help with air flow?? Have seen several xl-76 saws that did not have screen, any input would be appreciated thx Two things that will help if they haven't been addressed. Make sure the check valve in the gas cap is functioning. Higher pressure in the fuel tank raises the boiling point of the fuel. The space between crankcase and the fuel tank needs to be clean. There's a piece of black tube stuffed into the space on the clutch side to keep crud out and it's open on the flywheel side. Make sure there's no building up of crud in the space that will transfer heat to the tank. Put the black tube back in if you pull it to clean the gap out. Boiling gas has been a long standing issue on the older saws and gas can boil at temps as low as 95 deg F at atmospheric pressure. Plastic tanks have been a big improvement. Don't take the screen off the recoil. It's there to prevent chips from getting in. |
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Post by kevinm1980 on Sept 8, 2021 10:25:46 GMT -5
Have cleaned that gap and have changed duckbill and bronze filter, gonna look at muffler.. And I know ecreen is there for a reason but there are alot on xl-76 that do not have screen, just have to be more diligent about cleaning after use
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Post by charles on Sept 8, 2021 10:46:05 GMT -5
A few more things to check : Gasoline that is a winter blend is more volatile and will boil at a lower temperature . Is your fuel mix using ethanol gasoline ?
Ethanol gas will boil at a lower temperature also . Check your fuel filters , both in the tank and in the carb inlet . A restricted filter can pass enough fuel to work in
a low load condition , but lean out in a heavy load when in the cut . Is the spark plug the correct heat range ? How is the color of the plug after a hard cut ?
In the old racing days , to get an accurate color on the plug , we used a new plugs and cut the ignition off at the end of the run with no idle time .
Charles
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Post by edju1958 on Sept 8, 2021 10:52:17 GMT -5
Do you have a spark arrestor screen in the muffler?If so this could retain excessive heat.Many saw mfg.put the screen in their saws because it was required by federal law to prevent forest fires.I have taken the screens out of just about every saw I own.I don't cut on state or federal lands so it's not required.I've been cutting wood for almost 50 yrs.& have never started a forest fire with a saw yet.
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Post by kevinm1980 on Sept 8, 2021 11:03:37 GMT -5
Do you have a spark arrestor screen in the muffler?If so this could retain excessive heat.Many saw mfg.put the screen in their saws because it was required by federal law to prevent forest fires.I have taken the screens out of just about every saw I own.I don't cut on state or federal lands so it's not required.I've been cutting wood for almost 50 yrs.& have never started a forest fire with a saw yet. It doesn't just the baffle, but either way I'm gonna pull it apart once again and see what I can do, make sure the muffler is sealing properly, and take it out again for a burn this weekend |
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Post by kevinm1980 on Sept 8, 2021 11:05:06 GMT -5
A few more things to check : Gasoline that is a winter blend is more volatile and will boil at a lower temperature . Is your fuel mix using ethanol gasoline ? Ethanol gas will boil at a lower temperature also . Check your fuel filters , both in the tank and in the carb inlet . A restricted filter can pass enough fuel to work in a low load condition , but lean out in a heavy load when in the cut . Is the spark plug the correct heat range ? How is the color of the plug after a hard cut ? In the old racing days , to get an accurate color on the plug , we used a new plugs and cut the ignition off at the end of the run with no idle time . Charles Always use shell 91, will double check plug thx |
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Post by kevinm1980 on Sept 8, 2021 17:45:23 GMT -5
A few more things to check : Gasoline that is a winter blend is more volatile and will boil at a lower temperature . Is your fuel mix using ethanol gasoline ? Ethanol gas will boil at a lower temperature also . Check your fuel filters , both in the tank and in the carb inlet . A restricted filter can pass enough fuel to work in a low load condition , but lean out in a heavy load when in the cut . Is the spark plug the correct heat range ? How is the color of the plug after a hard cut ? In the old racing days , to get an accurate color on the plug , we used a new plugs and cut the ignition off at the end of the run with no idle time . Charles Actually looked at plug its a nkg bpm6a, replaced it with a rj-7 will see what happens |
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Post by xl130 on Sept 8, 2021 19:18:04 GMT -5
My 130 boils as well. It’s completely rebuilt and not a spot of grease on it hardly. Possibly the tank vents are a bit tight but as mentioned…,,there’s a lot of possible causes. The tank sits directly on the crankcase. Lots of heat transfer going on there I would imagine.
I don’t really worry about it much. I’ve never had it quit yet but I certainly open the tank cap slowly off I refill after a heavy run…..
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Terry Machinery Co.
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Post by Terry Machinery Co. on Sept 8, 2021 21:21:56 GMT -5
Is the spark plug the correct heat range ? Charles Actually looked at plug its a nkg bpm6a, replaced it with a rj-7 will see what happens One heat range colder on the spark plug will probably not make much difference. NGK:BPM6A is equivalent to a Champion:CJ8Y. Champion:RJ-7 was the originally equipped plug. Champion:CJ6 is also commonly used on this model. Champion:CJ4 - NGK:BM7A may "slightly" lower temps. Any compression increasing mods ? ( Base gasket delete...etc ) , Or a thick layer of carbon on the piston crown... increasing compression and impeding heat transfer ? |
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Post by kevinm1980 on Sept 9, 2021 8:01:02 GMT -5
Actually looked at plug its a nkg bpm6a, replaced it with a rj-7 will see what happens One heat range colder on the spark plug will probably not make much difference. NGK:BPM6A is equivalent to a Champion:CJ8Y. Champion:RJ-7 was the originally equipped plug. Champion:CJ6 is also commonly used on this model. Champion:CJ4 - NGK:BM7A may "slightly" lower temps. Any compression increasing mods ? ( Base gasket delete...etc ) , Or a thick layer of carbon on the piston crown... increasing compression and impeding heat transfer ? Had the jug off a few months ago carbon not the issue no compression mods either, Wil run it this weekend, it's gonna be a little cooler here in Edmonton |
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