Another rookie post DCS6421

[BJD85]

I just purchased a new makita 6421. Turned the H out 1/4 turn for break in. Didnt think to check where they where when I got from home depo as it was slightly 4 stroking in the wood and I figure thats good enough for break in. Now ive got a few tanks in it and and went to retune. I noticed they had the H 2 full turns out. And L 1 1\2 out. I looked up factory setting and found in pic below. Correct me if im wrong but could I theoriticly just tune to those settings in the pic? If I found the right carb that is. Then reset idle to 2500 Rpm? My ear is not so good as im new and only have a junk tach I dont trust and,dedinetly dont trust my ear yet. Many of you have already told me this and sent me stuff but I'm just not trusting myself i guess. I looked up hours and hours of vidios on this. Maybe just thinking way too much into it. Really dont want to blow her up. Any info is appreciated.

 

[CausticUC]

Those are reference starting points and may not be correct for your altitude, current ambient temperature, quality of oil+fuel mix, etc.

You would best of be finding a tach you trust and learn to read your plug.

 

[huskihl]

Your saw has a rev limited coil at 13,500 rpm. Once the saw is warm, if you start rich, say 2 turns out, and lean the h jet 1/4 turn at a time, revving the saw up in 1 or 2 second bursts, you can hear when the rpm's quit climbing. At 13,500 rpm, that should be a safe tune to operate at.

 

[Jasonrkba]

I used to do it by ear but I use a tach now. That way there is no guessing.

 

[BJD85]

Pulled the plug on my old saw to see how bad it was. Ran this saw hard before I even knew what tuning was. Live and learn. Looks to be carbon fouled? ( RICH ) am I reading this correctly?

 

[cuinrearview]

Yes black is too rich, crappy mix oil, or both.

 

[Wood Doctor]

When tuned right, these saws run like gangbusters. It's the best ripping chainsaw that I have ever used for cutting slabs:

 

[CausticUC]

Far too rich for me, your plug is pretty oil fouled.

Your saw was not lugging at all? Most times oil fouling will steal power from the top end as you will not fully combust your fuel.

 

[BJD85]

I had no clue what I was doing with that saw. That plug is from my first saw that was a craftsman and yes it was not acting correctly but I ran it anyway with ignorance. I just purchased a 6421 and was the real reason I started this thread and since then have learned all the basic saw needs. Was just curious about how bad my old one was. Defitetly wont be making those mistakes on my 6421

 

[CausticUC]

As it is not mentioned directly on the second chart, once you get your settings close, you will need to pull your plugs hot to read them and use a couple new plugs each time you read it.

The ceramic and electrode will vary in color when cool. As you are not racing or running at the edge, you just want to be slightly on the rich side of ideal. Any place in the top OK, Better, Good on the first chart.

Do not obsess with the perfect reading unless you have plugs for free for some reason.

 

[computeruser]

I think you may be overthinking it. Testing with multiple fresh plugs?! That’s something!

I’m still on the original plug in my 7900 from 2004, and I’ve been fine tuning by tach (at first) and then by ear in the cut. Saw still runs and cuts strong as can be. Don’t recall I’ve ever pulled the plug, much less changed it. Same with my trimmer, edger, other saws (except the Husqvarnas that need a rope stuffed in the cylinder when pulling the clutch to replace the rim sprocket), snowblowers, and generators. Good gas, good oil, and modern plug technology seems to make the periodic plug swap a thing of the past.

 

[CausticUC]

I think you may be overthinking it. Testing with multiple fresh plugs?! That’s something!

I’m still on the original plug in my 7900 from 2004, and I’ve been fine tuning by tach (at first) and then by ear in the cut. Saw still runs and cuts strong as can be. Don’t recall I’ve ever pulled the plug, much less changed it. Same with my trimmer, edger, other saws (except the Husqvarnas that need a rope stuffed in the cylinder when pulling the clutch to replace the rim sprocket), snowblowers, and generators. Good gas, good oil, and modern plug technology seems to make the periodic plug swap a thing of the past.

Never raced anything before or rebuilt it over the edge?

Most people do not really get too exact, just being close is enough... on the right side that is. In the case of saws, a bit rich.

Mainly it's something to be aware of and only requires dialing in once for most machines.

 

[BJD85]

Ok last one what y'all think? A tad rich? This was pulled hot after a going through a full tank.

 

[EngineNoO9]

I'd say based on that only it looks ok but it'd be nice to hear it in and out of the cut. I don't have a great ear for it but I'm getting better. Also I'd rather be a hair on the rich side anyways. So if it's 4 stroking out of the cut and cleans up in I'd be happy and leave it.

 

[CausticUC]

Maybe, maybe not; do you know what your wot rpm is at?

As this is a new saw, it is quite likely many guys here would recommend running a few tanks through on the richer side to break it in. Which is about where this looks.

After a few tanks, look again. Indexing, a small adjustment to the carb, or a small gap adjustment would put you right where you need to be, it will likely be pretty close after things get a little exercise.

 

[BJD85]

Yes its a new saw only a few tanks yet. WOT rpm is set to 11200. Max is 13500. Thats 1 1/4 turns out. L is set 3 1/8 out not shure of idle but its ideling at 2200-2300 and Its runnings great. Burbles out of cut No stalling no,bogging good trigger reaponseand just ripps. I'm running VP 40:1 just wantes to make shure I'm completly on the right track as im learning. Did notice some chunky dirty oil running down the seam of the muffler today the center where the two pieces are crimped and sealed together. Cant tell if its just bar and chain oil or what. It is not coming out of the screened port its dry there. It's mostly towards the back top end and dripping down. Really hope I dont have a bad seal to front end. Going to run it with no B N C or BnC oil tomarrow. But new saw and and I'm a rookie so not freaking out. I cleaned it up already so can't send pic. I'll post a vid of some cuts tomarrow if I get the time. Thanks for all the help guys.

 

[BJD85]

Right side of pic is oil running down from top of muffler. Best pic I could get and cleaned most off.

 

[BJD85]

Couldn't post the vidio still trying. This oil is coming down feon the top of muffler was actually bubbling a bit under thw screw. Anyonebknoq what this is from. Only happens while in thw cut. Its a little rich for break it 1-1/4 tirns

 

[huskihl]

Oil spooge. Still running quite rich

 

[CausticUC]

Oil spooge. Still running quite rich

Hard to say if it was leftovers from earlier, should burn off soon.

Not sure I ever had that happen on a saw before.