Finally got 2-stroke engine burble!

[fsfcks]

OK, so this is not a chainsaw engine but a box-store Husky multi-attachment strimmer. With the warmer and much more humid weather it was needing the carb re-tuned as it was lacking power (too rich). I reset the H/L jets to factory settings and using a tach adjusted them from there. Between the tach and the noise I could detect the cross-over point and actually heard the burble for the first time, just at the edge of not too rich.

Now if only I could tune my Dolmar 5100S as well as that I'd be happy! My MS441 is easy to tune in comparison.

 

[rmihalek]

What kind of rpms do those trimmer engines turn?

 

[KRP]

With your strimmer setup with a mild burble, you may find more smoke at lower throttle speeds. But, you will enjoy the full throttle extended weed thrashing power!

 

[fsfcks]

It is a Husky 128CD for use around my home, and the max shaft rpms are < 8,000 rpm. I've tuned mine around 7400 rpm. I have a slight stall from idle to high, so probably need to re-adjust the low setting.

 

[dswensen]

But ....

It is a Husky 128CD for use around my home, and the max shaft rpms are < 8,000 rpm. I've tuned mine around 7400 rpm. I have a slight stall from idle to high, so probably need to re-adjust the low setting.

I thought I read on here that string trimmers and blowers are always under load at full throttle, so tuning them to "4-stroke" means they are too rich?????

 

[fsfcks]

You could be right. But there is very little H screw adjustment range from 4-stroking to hitting maximum rpms, so I erred slightly on the rich side to avoid too lean operation and potential damage.