Hot weather chainsaw tuning??

[holeycow]

Maybe you should check one out. It's only deficiency is a spur drive.
I don't defend stuff stuff simply because I own it. I defend this one because it's probably one of the best 40cc saws ever made.

 

[TBS]

How do I go about adjusting it to run the correct amount richer?
Thanks for the help.

I just turn off saws, no idling

Some people use a pick awl or some form of screw to remove the limiter caps, past that you may normal slotted mixture screws, splined, or something else

 

[muscle_garunt]

It’s not black magic, it’s carburetor tuning. It’s a dark art but not too hard to understand. I’d venture to guess that if you held the saw trigger wide open and gave the rope a pull the saw would start right up. What are you doing in this situation? You are adding a big gust of fresh air to the initial charge upon starting. Release the trigger and I bet it idles pretty good and works as you’d expect upon giving it some throttle. So the solution to your issue is as simple as leaning the low speed circuit a little bit or turning up the idle. Get the saw running and idling then turn up the idle until the chain spins without you giving it any throttle. Then turn it down until the chain stops spinning then go a little more just for good measure but not too far. You want a rat-a-tat-tat idle not a ding-ding-dong idle. (Technical Terminology)

 

[redhawk23]

Thanks for the information.

Once the carb is tuned for winter gas and hot weather will it need to be tweaked again for cold weather? I imagine a repair shop does such tuning all the time if this issue is so common.

 

[Huskybill]

I’m not sure about the newer saws but I found out decades ago there are winter and summer carb adjustments. I figured out the high speed circuit is adjusted to the saws max rpm specs. It the low speed screw that needs re adjustments in the fall and springtime.
Right around September/ October when the chill in the air the carb low speed jet needs to be rebalanced. Then it’s good till spring.

I can’t run a saw unless it’s tuned correctly.

 

[muscle_garunt]

It’s not rocket surgery guys. Winter and summer gas are not the issue. It’s the delicate balance of fuel and air. Set the low speed for instant trigger response. Set the high speed for a slight burble wide open with no load but it should clean out and pull strong in the cut.

 

[SteveSr]

It’s not rocket surgery guys. Winter and summer gas are not the issue. It’s the delicate balance of fuel and air.

Air density changes significantly enough over temperature to cause tuning issues. A saw that is correctly tuned for 80F will be too lean at 40F. Similar issue happen with changes in elevation.

 

[lone wolf]

I guess you don'thave a clue about a Makita 4300. It's a very well constructed, mag case, adjustable oiler, open port saw that will run with and even outrun some decent 50cc saws. My Dolmar 420 is a beautiful little saw.

I love my Dolmar 7900 .

 

[BradSt]

It’s not rocket surgery guys. Winter and summer gas are not the issue. It’s the delicate balance of fuel and air. Set the low speed for instant trigger response. Set the high speed for a slight burble wide open with no load but it should clean out and pull strong in the cut.

Winter fuel can absolutely be a factor. I've seen it many times (quite a bit with ethanol free fuel from an area that doesn't go through very much, so it is out of season). Winter fuel will vapor lock very easily on a hot day, and make hot restarts next to impossible. Not saying the jetting isn't an issue, but I wouldn't tune it on out of season fuel. I'd rather have E10 fuel that is only days old in the tanks, vs E0 fuel from the winter. Just because you just bought the fuel, doesn't mean it isn't out of season.

 

[sbhooper]

I have always tuned my saws to colder temps and then they just run a bit richer during the summer. No big deal. I have never had vapor lock issues with any fuel. Shouldn't the new m-tronic systems adjust for that, now?

 

[redhawk23]

The saw is apparently tuned for cold weather/winter gas--thus the problem. It's a bad problem, I can use it for 10 minutes and it has to cool down for a long time before it will start again. Close to an hour.

The carb does have limiters on it, a shop that worked on my Dolmar either removed caps and/or replaced what was there. Maybe put in a screw in place of what was there? I won't be tuning it until that is done for this Makita.

Is it true that if I ran the current ethanol gas at the stations I won't have this problem?

Also, if I were to correct the problem by tuning the saw is it only a matter of tweaking the low setting?

Thanks again

 

[Huskybill]

First make sure your airfilter is squeaky clean before adjusting the carb. If your fouling sparkplugs your carb adjustment is off. Once the carb is adjusted correctly you should never foul sparkplugs.
Every fall when the weather cools down the saw will run erratic, blubbery response wise that’s letting you know the low circuit needs adjustment. I never touch the high speed circuit if it’s adjusted for the suggested max rpm. Then around springtime it gets adjusted again. Don’t forget the fuel mixture is also part of the cooling too.

 

[lone wolf]

The saw is apparently tuned for cold weather/winter gas--thus the problem. It's a bad problem, I can use it for 10 minutes and it has to cool down for a long time before it will start again. Close to an hour.

The carb does have limiters on it, a shop that worked on my Dolmar either removed caps and/or replaced what was there. Maybe put in a screw in place of what was there? I won't be tuning it until that is done for this Makita.

Is it true that if I ran the current ethanol gas at the stations I won't have this problem?

Also, if I were to correct the problem by tuning the saw is it only a matter of tweaking the low setting?

Thanks again

I have found the crap pump gas to be nothing but trouble this time of year. Try to get some canned gas like VP 94, in the meanwhile keep the gas can and the saws out of the sun as much as possible.

 

[LogSawyer74]

I have found the crap pump gas to be nothing but trouble this time of year. Try to get some canned gas like VP 94, in the meanwhile keep the gas can and the saws out of the sun as much as possible.

that's my new plan too! I mostly run my saws in the cold during fall and winter. Most all mine run like crap (i've turned into a tuning snob that's constantly listening and adjusting) during temps over 85. But I've found it's a lot better with canned fuel in the heat. Since I rarely run them in the summer, I just buy 2-3 cans of VP or TrueFuel and try to keep the saw out of the sun when not cutting.

 

[SAWMIKAZE]

Doesn't sound like a capable, knowledgeable, sawyer.
Don't quit now you were on a roll

I know some outstanding cutters that are utterly clueless about tuning a chainsaw.

Using it is one thing, working on it is another for those guys...

 

[SAWMIKAZE]

You are correct, but I have never seen a 42cc pro saw. Is this one or are you just defending them because you got a good one? Doesn't sound like the OP got a good one. Can you name one logger that uses this saw all day and all week for his primary tool? You can include Canada.

Ms 241.

 

[lone wolf]

Ms 241.

 

[lone wolf]

that's my new plan too! I mostly run my saws in the cold during fall and winter. Most all mine run like crap (i've turned into a tuning snob that's constantly listening and adjusting) during temps over 85. But I've found it's a lot better with canned fuel in the heat. Since I rarely run them in the summer, I just buy 2-3 cans of VP or TrueFuel and try to keep the saw out of the sun when not cutting.

Sounds like the best plan.

 

[KASH]

I dont know if our gas is different here in Canada but I buy pump gas that is ethanol free.I stock pile as I have a lot of different types of equipment at several different locations.Some cans are probably two maybe three years old purchased at all seasons of the year.I have never noticed any different tuning issues with winter or summer fuel.I do what Husky Bill says adjust the saw for the weather.
Kash

 

[redhawk23]

The MS 362 I use for one of my jobs runs well all winter and summer without re-tuning. We have gas delivered to the property so it’s not the same as what goes in the Makita.

I bought carb adjusting tools that came with a tachometer (cheap, I know). Tuning it will be a matter of adjusting the low setting to get the saw running again once it quits?
I suppose before I do that I’ll get new gas in it. Maybe that will fix the problem by itself.
Thanks