Aftermarket Coil on Makita DCS6401

[MMG]

I started this in the Sachs Dolmar Thread but I think that was in the wrong place so here is a repeat.

I have a Makita DCS6401 that I replaced the coil on. It starts and runs but misses bad when I rev. Rebuilt the carb, checked the gaps, new plug, fresh gas but it just won’t rev. The A/M coil I bought said it works in a Dolmar 6401 and others but only lists Makita 6400&7900. It seems like the timing is advanced to me. Could there be a timing difference from a M6400&M6401? Box says it replaces the 038143041 which I think is the OEM unlimited coil. Asking for input before I break down and go OEM.
BTW, I didn’t remove the welsh plug I just blew everything out with carb cleaner and compressed air.

Vid of it kind of running attached

 

[cuinrearview]

Was this one of the sub-$20 Chinese Ebay coils by chance?

 

[MMG]

More like $80ish for a "red" Chinese coil the sub $20 is for a much smaller saw I think. Yes, that is what I think too. Just wondering if anyone else has had similar issues with these Chinese coils. Has anyone had issues with the flywheels going bad on these saws? Are there any differences in the coil on the 6400,6401,6410, ect besides the RPM change in the newer saws? I have another good running saw that I could swap flywheels with but I really don't want to take apart a running saw to test....prolly what I'm gonna have to do....ugh

Thanks,

 

[cuinrearview]

Subbing known good is pretty surefire. $80. Ouch. I see OEM maroon on the bay for that occasionally.

 

[MMG]

Yeah, I pulled the trigger too quick I think but in Dec20 I think prices were going through the roof on a lot of things. Also, with suckers like me who will pay they’ll get what they can get. At the time the OEM coils were crazy high too.
I found OEM coils online now for not much more than I paid for what appears to be junk.
Still waiting on some answers so I’ll let this ride awhile before spending more cash.

 

[MMG]

Fixed! Changed out the flywheels this morning from my other 6401 and it runs perfect. Revs up and hits the limiter like it’s supposed to. Weird that the flywheel was the problem. I put the bad flywheel on the other saw to check and it has the same issue, runs good down low but misses at high rpm. Oh well, gonna get a new flywheel to slap on the BB saw and I’ll be back to having four running saws with different setups. I’m wondering now if my old coil was bad.

 

[MMG]

BTW, both flywheels are OEM but have significant differences. Any thoughts on that?

 

[Wood Doctor]

Your old coil is likely still good. It might have been easier to have swapped it rather than swap flywheels. Things like this drive repairmen bonkers. Welcome to the battle.

 

[huskihl]

BTW, both flywheels are OEM but have significant differences. Any thoughts on that?

I bet the bad one is from a different saw. There could be differences in the fw between the half dozen or so 64/7900 variants but I’ve never noticed it

 

[MMG]

I got both saws used over 10/12 years ago. One had a BB kit in it( I stole the good FW from it) so I know it had been worked on. It does look like it had not been messed with much beyound that though. The other one is stock and I bought it non running real cheap. It looked like it had been into pretty deep as the plug wire was buggered up some and the carb was a mess, a few other indicators. After a new carb kit and gluing down the Welch plug it had been flawless for years until this. Finished putting it together last night and made a few cuts. Running good now.

 

[MMG]

Your old coil is likely still good. It might have been easier to have swapped it rather than swap flywheels. Things like this drive repairmen bonkers. Welcome to the battle.

Gotta take off the fly wheel to get yo the coil on this saw. I wished it were that easy, I would have swapped out parts from my other saw before giving in this deep. Thanks

 

[ballisticdoughnut]

BTW, both flywheels are OEM but have significant differences. Any thoughts on that?

There was/is a recall on some 6401 and 7901 models due to possible flywheel failure. By failure I mean explosion. The design was changed at least once that I know of.