# Carb Tuning



## Machold (Nov 16, 2009)

I need to know how to tune (set) the carb on a new Makita/Dolmar 510 chain saw, the reason being the EPA demands saws be set to run lean for emissions control, but running lean will lead to piston head burning/scoring. I need to set it richer but not too much so that performance would be diminished. I'm a total novice. Thanks.


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## Airman (Jan 7, 2009)

What brand and model carburetor is installed on your saw? The parts list only shows the Dolmar assigned model number. The carburetor manufacturers all have websites and have downloadable instructions to adjust, rebuild and more.

Walbro:
http://wem.walbro.com/distributors/servicemanuals/

Tillotson:
http://www.tillotson.ie/till3.html

Zama:
http://www.zamacarb.com/tipspage.html
http://www.zamacarb.com/tips.html


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## Machold (Nov 16, 2009)

Thanks for the reply; don't know, haven't taken the cover off, yet; will the carb have a name on it, maybe?


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## bec98x (Jan 5, 2007)

I know that the EPA has guidlines but the saw should be fine as is when using it as designed. If this is a new saw messing with the adjustments can only void the warranty.

You should be able to take it to a Makita service center and they can check to make sure that it is set properly.

Yes lean can cause cooling problems and lead to seizures but not letting it warm up or running some of them near 1/2 or 3/4 throttle can also be cause for running lean. Don't fully understand why but saw a presentation from one of the saw manufacturers.

Plus EPA fines are steep!

Remember 1/16th of a turn goes a long way.


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## geogrubb (Jul 28, 2006)

My $0.02;
Don't adjust anything;
The simple solution is to inrease the oil in the fuel mix, if it calls for 50:1 mix, increase it to 40:1 or 32:1, all the lean requirements are for EPA. The people making the rules don't have to cut wood so it is easy for them to tell everyone how to burn up their equipment. A lot of old Lawnboy 2 cycle are still running at 16:1, you will have more carbon buildup with a richer mixture but an engine that will last a lot longer. Have a good one. Geo


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## Machold (Nov 16, 2009)

Thanks for the 2 cents, much appreciated. I got this advice from another pro:
"Increasing the oil in the fuel mix will not slow a chainsaw engine very much, richening up the H setting will and its the high rpm and lean setting that is causing the problem. Extra oil in the mix will help more than hinder an engine, it will not cause very much carbon build up using modern mix oils. ...tune the carb a little rich, mix fuel 40:1 with good brands of mix oil and run the saw like it was intended. ...Set up as they have been coming from the factory they are failing with less than 20 hours on them."

Thanks for all opinions.


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## geogrubb (Jul 28, 2006)

I use nothing but Stihl oil in my 2-cycles, if it's good enough to run their equipment at 7-10,000 rpm all day every day, it's good enough for me. Have a good one. Geo


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