Tuning for elevation videos/question

[davidwyby]

Went up the hill expecting to have to retune but it cleaned up as soon as it touched wood so I left it. Also lazy and didn’t bring tach... should I have tried leaning it? Hmmm... ? Def lost some power, it’s a 20” saw up there.

Drug some wood home to try under da sea

And some oak at 3,000’ on the way home for grins.

 

[drf256]

I’m assuming ambient temp the same?

Tune sounded good on both. Surprised it wasn’t blubbering at 7600’.

FWIW, when we did our 044/446 buildoff’s a few years ago for the MMSW GTG, I had to drill the jet in an HD17a to get saw to be fat enough 1.25 turns out on the H at my home 230’ASL location @ 60*F. Randy is at 2300’ and that particular day was 89% and quite humid. My saw wouldn’t lean out with the H needle seated. I had to buy a factory carb just to even consider competing.

 

[davidwyby]

Oh, no, not the same...that's why I go up there. Was probably 55-60 up there in the am and a bit more humid than down here in the afternoon, which was 90-95° and dry. Maybe that explains it. I was surprised it wasn't pig rich.

 

[davidwyby]

@Lightning Performance

 

[Lightning Performance]

@Lightning Performance

I don't think I'm every going to get a carb needs the jet drilled. Just opening up the muffler makes most of them fat. I test around 60 ASL or less. The dense humid air of the hot summer never wants more fuel. I run 1.5 turns out in the dead of winter. Ported saws maybe 1.7. Tops on my mill 084 in freezing cold weather is maybe 1.5 down near 12K or less. As it warms the saw gets a bit leaner never fatter in cold dry air most times. Why bother with jets. Some people like factory settings. So far so good here.
Now the 361 is a different story. It runs out of fuel with a good port job. Trying to get it back is a waste if time imo. The carb is too small by then. It will run ok till you get in a long cut with a long bar.

 

[Lightning Performance]

Under the sea sounded the fattest to me but three more cuts and they start warming up.

 

[Lightning Performance]

My heavily modded 362 carb V1 seems to be less finicky than any other saw to temp, elevation or weather changes. The Mtron is best on the stock saws. That one saw is always very close and needs little to get just right on the H. I never touch L but this carb has mid throttle bled ports and a double air entry. The tune is now in half the volume. Dry air flow never changes. Makes no sense but it works. Bass ackwards