Chainsaw Repair
How To Basics - Carb Fixes + Mods - IPL and Service Manuals => How To Basics and Fixes => Topic started by: man of stihl on November 29, 2011, 03:34:49 pm
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Has anyone ever did a time comparison on a ported saw with a opened up muffler and no muffler at all? I raced against a guy last summer that did not use a muffler. And he does very well actually.
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Meaning he ran it coming out of the cylinder without anything or with just a short stub of a pipe ?
Generally speaking straight out the cylinder they have to be set extremely rich to idle ,like blowing black smoke .In doing so they load up and don't spool up to speed right .
I've seen muffler race saws that had nearly all the front of the muffler carved out but they were running big Tillotson model HL carbs with double pumper diphragms as to get just oodles of fuel through them . Most standard saws use just a large enough carb to be ample to supply enough fuel under standard run condition .Often times an open exhaust will in essence "over run " the carb in other words provide no back pressure and thus the engine draws more fuel than the carb can supply .
I tried a cut out front muffler on one of my 038 Mags that runs real well for what it's design is .It did in fact over run the Bing carb and didn't do as well as I thought it should have .
Another example is an old gear drive Mac that I used to run open .That thing would blow black smoke as though it were burning old tires .Then huff and puff hiccup and fart until it got all that fuel cleared out while under load .All this took about 5 seconds then it was like an after burner on a jet kicked in .Took off like cat that had been turpentined with a corn cob .
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He had nothing bolted to his cylinder. He didn't have to worry about idling either because it was a cold start race. Wide open from start to finish.
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Lot of shows have rule in place for muffler must be on saw. Thats why you see gutted shells on the stock appearing saws. No muffler just a shell straight out.
What was the rules for this show and was it a gas or alky saw? PM me the show if you dont know and I will give it a look see. ;)
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my wildthing has no muffler at all and it runs good, revs quick too