The tuning video thread

[Sprinter]

Coil sometimes too.

Are you saying that a failing coil will affect idle? What are the symptoms?
I think I may have one on my hands!

 

[huskyboy]

Are you saying that a failing coil will affect idle? What are the symptoms?
I think I may have one on my hands!

Best way I can describe it is the saw will seem to have two idle spots (it won’t tune consistent on the idle) and it’s either the carb or the coil. Sometimes the saw won’t start when hot either. I’ve dealt with a few wonky coils on Husqvarnas. Mostly 372, 394 and 390’s. Seems like husky coils die slowly and stihl coils either work or they die completely.

 

[huskyboy]

Part of the problem imo is the limited coils on the 372 and 390 have a advance curve that starts at 3200 rpm or so and the idle jumps around if you have the idle set high. Seems some coils are worse than others and a bad carb makes it even worse. Especially a bad rwj carb. The HD and WJ are better mannered. I prefer to swap in the black unlimited coil that has a more fixed curve. They seem to idle better.

 

[kneedeepinsaws]

This would have saved my poor 346XS

Quite a few tuning vids on YouTube all with saws that run properly. None with troubleshooting tuning issues

 

[Sprinter]

Best way I can describe it is the saw will seem to have two idle spots (it won’t tune consistent on the idle) and it’s either the carb or the coil. Sometimes the saw won’t start when hot either. I’ve dealt with a few wonky coils on Husqvarnas. Mostly 372 and 390’s. Seems like husky coils die slowly and stihl coils either work or they die completely.

My problem is a 30 year old 272xp that came with a no idle complaint. First thing I found was a dead coil so, I haven't been able to confirm the idle problem.. A the moment, I am waiting for a replacement. Pulled the muffler and it's all bright & shiny inside.

 

[davidwyby]

Best way I can describe it is the saw will seem to have two idle spots (it won’t tune consistent on the idle) and it’s either the carb or the coil. Sometimes the saw won’t start when hot either. I’ve dealt with a few wonky coils on Husqvarnas. Mostly 372 and 390’s. Seems like husky coils die slowly and stihl coils either work or they die completely.

Part of the problem imo is the limited coils on the 372 and 390 have a advance curve that starts at 3200 rpm or so and the idle jumps around if you have the idle set high. Seems some coils are worse than others and a bad carb makes it even worse. Especially a bad rwj carb. The HD and WJ are better mannered. I prefer to swap in the black unlimited coil that has a more fixed curve. They seem to idle better.

kinda sounds like my 2166, “two idles”

 

[Sprinter]

My problem is a 30 year old 272xp that came with a no idle complaint. First thing I found was a dead coil so, I haven't been able to confirm the idle problem.. A the moment, I am waiting for a replacement. Pulled the muffler and it's all bright & shiny inside.

So I got the new coil and got it fired up. He was right, it wouldn't idle.
Did the carb cleaner trick and found it sucking air at the intake block/cylinder junction.
Cut a new gasket and it now idles but it has a few other issues to correct now.
It's been a hard 30 years, broken fins, worn-out starter & who knows what else.
It's gonna' be a project. Hope I can find parts.
Fred

 

[davidwyby]

 

[Benwa]

I think the main reason is how restricted the muffler is, and to a lesser degree port timing. Stock mufflers can be so stuffed up that there is little difference between 2 & 4 stroke sounds. Hearing protection may help filter out high frequency noise, so you can better hear the 4 stroking.

I completely agree with this. I have a very "keen" ear, but if I take my muffs off or ear plugs out, I can't hardly discern a 4-stroke sound. It's amazing the difference it makes.

 

[Red97]

More sounds/power. Shows how extreme tunes effect power. And a little on how to correct them.

 

[cus_deluxe]

...another question. I have a couple saws that don’t maintain a steady idle rpm. Where does one look next in that case?

Thanks

X-torq saw?

 

[Vintage Engine Repairs]

A video I did a while ago. I don’t put enough hours on a saw to feel confident to push it to its limits, but this method has served me well. I use it for everything 2 stroke ope.

 

[davidwyby]

@Trains didn’t you post the stihl L tuning procedure once? Or @Stump Shot ?

 

[Stump Shot]

@Trains didn’t you post the stihl L tuning procedure once? Or @Stump Shot ?

Wasn't me. I did do this little ditty however...

 

[Stump Shot]

@Trains didn’t you post the stihl L tuning procedure once? Or @Stump Shot ?

The Stihl method attempts to force the tuner into getting the relationship correct between the Lo circuit and the Idle speed(throttle butterfly).
You will hear about and see quite a few saws that are leaned out too much and the throttle plate closed off to compensate for the idle speed to be low enough. Which can lead to erratic run issues from going wot to idle as the throttle slams shut and closes off the air much too abruptly.
This of course would seem to be aimed at the more amateur tuner and not the well seasoned one, which would by my guess about the whole affair.

 

[davidwyby]

I tend to go fatter and fatter chasing throttle response and end up opening the throttle screw more to compensate. I wanted to try the stihl method to see if it was more concrete on the L setting.

 

[Trains]

@Trains didn’t you post the stihl L tuning procedure once? Or @Stump Shot ?

probably, was it the tuning a 460 saw that explained the process ?

this one ?

 

[davidwyby]

@Trains it was just the instructions for the L maybe on tree house. Something about 2800/3200 rpm back and forth with the L mix and idle speed screw.

 

[Trains]

yeah, thats covered on that video I posted too, saw rpm's vary by saw type and size, but you can get close with the above vid.

I think I remember putting something up at the tree house, but cant remember which post.

what the process does is to correctly set the butterfly at idle, and give you a good base to tune from, if your not already on the money doing it that way.
I have come across many saws where the butterfly was closed too much, and running lean, or open too much, and the L was way rich to make it work, and thus, other issues of saw not running right goes with each.

Ah the joys of people messing around with things they know nothing about, if there lucky, they dont toast their saw.

 

[pbillyi69]

i ususqlly run the idle screw in to keep it running and adjust the l screw until it just at the right spot back the idle screw out til the right idle number. then do the h screw by ear and check with the tach