Really good solution! The baffle / nut from my machine was clogged with a lot of carbon. I cleaned the baffle / nut, and then after running the machine without the baffle, I re-installed it. It ran a lot better, and I did not need to adjust the carburetor. Thanks for the help!
Thanks Steve, worked like a charm on my SH86C blower. Removed arrestor and the screen wascompletely clogged. Out of propane, so I used an engine carbon cleaner (Deep Creep) and sprayed it heavily and let soak on a paper towel - black goop was coming out immediately. Used a small wire brush and re-sprayed, re-brushed , and blew it out with compressed air. Luckily I had the 15 mm socket and a Corona with lime so the job was done right.
I like your info. less pressure less likely to heat up. I usually take of the screen then put the screw back on but now I'm going to take it completely off and get better performance doing it
My neighbor has the same blower. And his sounds the same because he did the same thing to the exhaust too. Because he said it kept losing power and would stall out.
If your blower was "tuned" completely out of whack like mine.... A good baseline to begin with is 1 Turn out on each screw.... Then Fine Tune from there... These are MIXTURE screws, so they operate like a water faucet... Counter clockwise (open) is Rich, Clockwise (Closing) is lean... ALSO...This is IMPORTANT... YOU MUST HAVE FRESH FUEL !! Not fuel you think is fresh, Not fuel Carl your Neighbor told you was Fresh... Not the fuel from that can that's been sitting since June...I MEAN FRESH FUEL ! Cannot stress this enough! Trust me on this one...
I've had a BG85 for about 10 years. It doesn't get a lot of use but has been a frustrating device that I could never tune so it pulled cleanly off the bottom, and I could never get it to rev out cleanly up top and it was difficult to start. The mixture locks were probably the reason for that inability to fine tune it. I've always run it on 91 octane as recommended and Castrol TTS Synthetic 33:1, same as my Stihl 034 Chainsaw and Husqvarna 343R Brushcutter. I switched to 98 octane about 12 months ago and drained the fuel out of the blower, put in the new high octane blend and it started easily and pulled off the bottom and revved out nicely without touching it. It was still a tad rich up top, but better than it had ever been before.......I did see this video today while looking for something else and took the spark arrester out, and I was surprised it didn't do that 10 years ago, pulled it off and put the plug back in the muffler without the offending arrester. Took those annoying mixture screw locks off and it has even more blow without the arrester and with some additional fine tuning it is running very crisply. These things are always set too Rich out of the box, they all do that, Cody73 set the mixture correctly by running it till it was too rich then backed it off a bit. I thought it was a bit loud running without the muffler plug so I put it back in. The spark arrester was only slightly blocked so that wasn't suffocating it, but it is so much better without the restriction caused by the spark arrester.....Highly Recommended.
I am not sure why you would want to Modify the muffler on a Brand New Stihl leaf blower. These things are well engineered to start. By removing the spark arrestor you risk throwing a spark and causing a fire. If you are blowing in wet conditions no problem....if not why do you even want to go there? IMHO The extra power you may gain is minimal.
+nbpt1000 1. Because the risk of causing a fire is practically zero unless you are blowing a huge pile of dry pine needles. 2. The difference in power, and throttle response is huge. Stihls are engineered to work as well as possible, while still conforming to government noise and emissions regulations. Being a private citizen, I don't have to worry about meeting those regs.
i threw mine out entirely. What happens is after a while they carbon up blocking the exhaust, even shorter if you are running the fuel mixture rich. So instead of getting a lot more back pressure from the spark arrest having carbon in it and having to routinely clean it with a wire brush or blow torch.
nbpt1000, the modification is well worth it. As is running high octane fuel and synthetic 2 stroke oil, always freshly mixed. The extra power gain is considerable, and pissing off the mixture locks gives a wider range of adjustment for fine tuning. Any restriction in a 2 Stroke exhaust will cause a power drop, and the spark arrester is a Resticter. I put the plug back in the muffler without the arrester because it was quieter, but hardly noisier than with the arrester. My machine is a BG85 that could never be tuned properly from new. I took it back to the Dealer for it's first check when it was 3 months old and asked them to try and tune it up, but they said, this is as good as it will ever get, probably due to the mixture locks and the spark arrester. I live in The Tropics and even in the dry months I think you'd have more chance of starting a fire by rubbing 2 sticks together. ;-)
@@harryrambo4564 i've had mine for the same amount of time. the old one actually run better than the 1year old identical one. engine probably not worn in. I use mine on a roof and don't need to worry about starting fires. A mate of mine at a stihl dealership told me to either burn the carbon off or throw it either way.
Stihl leaf blowers and other products, which I have no affiliation with, are built to run full throttle out of the box. Never attempt to modify any part. Treat them properly, regularly maintain, will run good as new. The carburetor jets will rarely require tuning. Usually only the spark plug and air filter need replacement or cleaning. After about 1 year of continuous usage the spark arrestor screen will need to be cleaned of carbon buildup. On the carb, the low jet screw is for setting the idle. The high is for full throttle. Just like a tap, clockwise closes, counterclockwise opens. The BG55 comes ready to go with factory set H & L carb jet settings, as specified in the manual, and way more credible than a UA-cam video. Don't mess with these unless absolutely must, and this will only be necessary after many, many hours of use. The spark plug, air & fuel filter and muffler must be completely operational to do this. The L is easy. Turn clockwise until shut. The open counterclockwise (cc) as per the manufacturer's manual recommendations . Prime the fuel, choke on, try a start. If doesn't start, cc a further 1/16", try again. Repeat until starts. The manual will advise on the proper factory cc setting. The H, the full throttle operation setting, is adjusted when the motor reaches maximum rpm/power output, trigger fully depressed, and once reached must tweaked back clockwise for a deliberate power reduction to ensure motor longevity. Ideally, locking at maybe 90% max. rpm. The H should never be set at 100% rpm or the motor will fail before its time. The L should be just enough to ensure uneventful idle. Both procedures are easy to do if one is familiar. If not, take the unit to a certified authorized dealer.
I modded mine 10 years ago and use it on a 3 time a week basis for about an hour each time never had an issue, removed the arrestor and then drilling out the muffler port hole so that it has no muffler at all. Retuned it and it runs like a angry hornets nest, definitely increased CFM flow due to higher revs. Always let your machines warm up at or near idle for a 1 or 2 min is the key to piston longevity. Iv never had to perform any repairs nor had any failures. 1 pull start every time.
Can you pls explain what your tuning process is? L and H, How to tune, Tune when engine is Hot of Cold? Can you lean it out too much and cause engine failure? Thank You
You can lean it out and, in any 2-cycle, lean is almost always catastrophic. You need to be very aware of the mods you do because these are reliable but sensitive engines.
Hugh Jazz Basically, because a muffler mod increases the exhaust flow, this leans the air/fuel mixture, you will have to compensate by backing out both the H and L screws a turn or two. When you get it started, let it warm up for a few minutes and then adjust the L until it idles smoothly but doesn't stall. Then hold open the gas - if it is too rich you will hear make a rougher, deeper sound. If it it is smooth, back out the H until it just starts sounding rough, to make sure you are not running too lean. Then, adjust the H inwards (leaner) until to smooths out. Next, check the throttle response. It should be very fast, you can play around with the L to see if it can improve the response. Finally, run it for a while moving it around, and holding it different positions and make sure it is not running rough at full throttle. If it sort of jumps between running rough and smooth, slowly turn the H inwards until it always runs smooth. It might should a little complicated but it is actually pretty simple and you should easily understand how it works when you start tuning it. Let me know if you have any other questions!
Really good solution! The baffle / nut from my machine was clogged with a lot of carbon. I cleaned the baffle / nut, and then after running the machine without the baffle, I re-installed it. It ran a lot better, and I did not need to adjust the carburetor. Thanks for the help!
Check your spark plug if you didn't adjust it, it's probably white and you're running too lean.
Thanks Steve, worked like a charm on my SH86C blower. Removed arrestor and the screen wascompletely clogged. Out of propane, so I used an engine carbon cleaner (Deep Creep) and sprayed it heavily and let soak on a paper towel - black goop was coming out immediately. Used a small wire brush and re-sprayed, re-brushed , and blew it out with compressed air. Luckily I had the 15 mm socket and a Corona with lime so the job was done right.
I like your info. less pressure less likely to heat up. I usually take of the screen then put the screw back on but now I'm going to take it completely off and get better performance doing it
How did that work?
My neighbor has the same blower. And his sounds the same because he did the same thing to the exhaust too. Because he said it kept losing power and would stall out.
If your blower was "tuned" completely out of whack like mine.... A good baseline to begin with is 1 Turn out on each screw.... Then Fine Tune from there... These are MIXTURE screws, so they operate like a water faucet... Counter clockwise (open) is Rich, Clockwise (Closing) is lean... ALSO...This is IMPORTANT...
YOU MUST HAVE FRESH FUEL !! Not fuel you think is fresh, Not fuel Carl your Neighbor told you was Fresh... Not the fuel from that can that's been sitting since June...I MEAN FRESH FUEL ! Cannot stress this enough! Trust me on this one...
Now that is what I needed to know, the baseline turn not the gas. Thanks !!!
thank you. blower runs like a champ :D
I've had a BG85 for about 10 years. It doesn't get a lot of use but has been a frustrating device that I could never tune so it pulled cleanly off the bottom, and I could never get it to rev out cleanly up top and it was difficult to start. The mixture locks were probably the reason for that inability to fine tune it. I've always run it on 91 octane as recommended and Castrol TTS Synthetic 33:1, same as my Stihl 034 Chainsaw and Husqvarna 343R Brushcutter. I switched to 98 octane about 12 months ago and drained the fuel out of the blower, put in the new high octane blend and it started easily and pulled off the bottom and revved out nicely without touching it. It was still a tad rich up top, but better than it had ever been before.......I did see this video today while looking for something else and took the spark arrester out, and I was surprised it didn't do that 10 years ago, pulled it off and put the plug back in the muffler without the offending arrester. Took those annoying mixture screw locks off and it has even more blow without the arrester and with some additional fine tuning it is running very crisply. These things are always set too Rich out of the box, they all do that, Cody73 set the mixture correctly by running it till it was too rich then backed it off a bit. I thought it was a bit loud running without the muffler plug so I put it back in. The spark arrester was only slightly blocked so that wasn't suffocating it, but it is so much better without the restriction caused by the spark arrester.....Highly Recommended.
50:1 is the ratio stihl equipment run on
Good piece of equipment!!!
I am not sure why you would want to Modify the muffler on a Brand New Stihl leaf blower. These things are well engineered to start. By removing the spark arrestor you risk throwing a spark and causing a fire. If you are blowing in wet conditions no problem....if not why do you even want to go there? IMHO The extra power you may gain is minimal.
+nbpt1000 1. Because the risk of causing a fire is practically zero unless you are blowing a huge pile of dry pine needles.
2. The difference in power, and throttle response is huge. Stihls are engineered to work as well as possible, while still conforming to government noise and emissions regulations. Being a private citizen, I don't have to worry about meeting those regs.
i threw mine out entirely. What happens is after a while they carbon up blocking the exhaust, even shorter if you are running the fuel mixture rich. So instead of getting a lot more back pressure from the spark arrest having carbon in it and having to routinely clean it with a wire brush or blow torch.
nbpt1000, the modification is well worth it. As is running high octane fuel and synthetic 2 stroke oil, always freshly mixed. The extra power gain is considerable, and pissing off the mixture locks gives a wider range of adjustment for fine tuning. Any restriction in a 2 Stroke exhaust will cause a power drop, and the spark arrester is a Resticter. I put the plug back in the muffler without the arrester because it was quieter, but hardly noisier than with the arrester. My machine is a BG85 that could never be tuned properly from new. I took it back to the Dealer for it's first check when it was 3 months old and asked them to try and tune it up, but they said, this is as good as it will ever get, probably due to the mixture locks and the spark arrester. I live in The Tropics and even in the dry months I think you'd have more chance of starting a fire by rubbing 2 sticks together. ;-)
@@knackers2773 Been running ours daily for work for nearly 7 years
@@harryrambo4564 i've had mine for the same amount of time. the old one actually run better than the 1year old identical one. engine probably not worn in. I use mine on a roof and don't need to worry about starting fires. A mate of mine at a stihl dealership told me to either burn the carbon off or throw it either way.
Stihl leaf blowers and other products, which I have no affiliation with, are built to run full throttle out of the box. Never attempt to modify any part. Treat them properly, regularly maintain, will run good as new.
The carburetor jets will rarely require tuning. Usually only the spark plug and air filter need replacement or cleaning. After about 1 year of continuous usage the spark arrestor screen will need to be cleaned of carbon buildup.
On the carb, the low jet screw is for setting the idle. The high is for full throttle. Just like a tap, clockwise closes, counterclockwise opens. The BG55 comes ready to go with factory set H & L carb jet settings, as specified in the manual, and way more credible than a UA-cam video. Don't mess with these unless absolutely must, and this will only be necessary after many, many hours of use. The spark plug, air & fuel filter and muffler must be completely operational to do this.
The L is easy. Turn clockwise until shut. The open counterclockwise (cc) as per the manufacturer's manual recommendations . Prime the fuel, choke on, try a start. If doesn't start, cc a further 1/16", try again. Repeat until starts. The manual will advise on the proper factory cc setting.
The H, the full throttle operation setting, is adjusted when the motor reaches maximum rpm/power output, trigger fully depressed, and once reached must tweaked back clockwise for a deliberate power reduction to ensure motor longevity. Ideally, locking at maybe 90% max. rpm. The H should never be set at 100% rpm or the motor will fail before its time. The L should be just enough to ensure uneventful idle. Both procedures are easy to do if one is familiar. If not, take the unit to a certified authorized dealer.
I modded mine 10 years ago and use it on a 3 time a week basis for about an hour each time never had an issue, removed the arrestor and then drilling out the muffler port hole so that it has no muffler at all. Retuned it and it runs like a angry hornets nest, definitely increased CFM flow due to higher revs. Always let your machines warm up at or near idle for a 1 or 2 min is the key to piston longevity. Iv never had to perform any repairs nor had any failures. 1 pull start every time.
Great help many thanks
Can you pls explain what your tuning process is?
L and H, How to tune, Tune when engine is Hot of Cold?
Can you lean it out too much and cause engine failure?
Thank You
You can lean it out and, in any 2-cycle, lean is almost always catastrophic. You need to be very aware of the mods you do because these are reliable but sensitive engines.
Hugh Jazz Basically, because a muffler mod increases the exhaust flow, this leans the air/fuel mixture, you will have to compensate by backing out both the H and L screws a turn or two.
When you get it started, let it warm up for a few minutes and then adjust the L until it idles smoothly but doesn't stall.
Then hold open the gas - if it is too rich you will hear make a rougher, deeper sound. If it it is smooth, back out the H until it just starts sounding rough, to make sure you are not running too lean.
Then, adjust the H inwards (leaner) until to smooths out.
Next, check the throttle response. It should be very fast, you can play around with the L to see if it can improve the response.
Finally, run it for a while moving it around, and holding it different positions and make sure it is not running rough at full throttle. If it sort of jumps between running rough and smooth, slowly turn the H inwards until it always runs smooth.
It might should a little complicated but it is actually pretty simple and you should easily understand how it works when you start tuning it.
Let me know if you have any other questions!
Cody73 Thank mate, really appreciate the explanation :)
Running mine without the arrestor, sounds good but super loud
I remove the spark arrestor on all my two smoke equipment.