west-
i didn't know it gets hot in b.c.
i like your ideas about the low speed adjustment.. i think it's more important now. newer epa carbs seem to run the H really lean and need the L richer to keep the saw working right at high rpm's. i just fixed an echo 670 that wouldn't start at all until you opened the L 2.5 to 3 turns. and to get it running right at speed required close attention to the L setting.
your experiences with the 346 sound similar to chris-pa's. thats a hot little saw, a screamer. maybe it gets too hot. if it will restart in 15 minutes, that sounds like a fuel issue to me. if it takes longer, electronics. the iron and plastic ignition module, bolted to the case, should take longer to cool than the carb and fuel lines. i also wonder if this sort of problem is more common on saws with purge bulbs. i've always thought they are a solution for a non-existent problem.
Ha-ha, yes sounds like It could be? I'm not a fan of the purge bulb. I eliminated it on that 346 as it wasn't the prime problem (bad pun srry lol) but certainly made the problem hard to diagnose. You are right, when I started reading Chris's OP, I figured it was the same thing until I read on. It was actually the opposite.
(Explanation below)
I personally have had terrible luck was carbs these past 5-6 years. (All Walbro)I have had as little as 4 months on a new carb. Quallity has droped somewhere? Its like night & day. After reading your posts I am strongly weighing towards the ethanol been the problem perhaps A higher content than they say at the pumps ("up to 10%"). Maybe because of the winter grades in Northan BC & AB chasing Gas & Oil and Mountain Pine Beetle work up there. I have never been In a position I could supply my own fuel but for now I'm just out of greater Vancouver Falling for property development and having read you post I realize I do have an Ethanol free source through Shell Canada (V Power) I will be shopping there from now in.
Great history you have come forth with, thanks.
It can get very hot up here. On the coast you may see a few days through the summer in the lower 90's but hot days would typically be between 80 to 87.
BC shares the Okanogan region with North Eastern WA and it's smokin' hot there. It's all orchards, BC puts out a lot of wine from there. Canada's only desert (Okanagan desert) in Osoyoos is the top of the Sonoran. Most of the BC interior is too hot for me.
It's possible a richer L might be helpful if you let it idle that way before shutting down, due to increased evaporative cooling from the extra fuel.
As to the 346 - it sounds like vapor lock. If you can get it to fire and chug a bit on full choke when it does it that will prove it. Of course, if it's not vapor lock you'll flood the heck out of it.....
Yes I do recall you saying you needed to choke it.
I Was and am referring to a richer low for these conditions.
A hard starting saw is an indication of a lean low. May not slow the response as it didn't in the case of the ported 357 in hot weather. It creates heat and seems to interfere with priming of sort?..I have no technical response for it. Although that's where I preferred to run the saw but it was set wrong for that temperature. Providing there is no other issues with a saw then a properly set low of a hot saw should fire up with a half a pull. If it needs a little more low in hot weather then that's what we do.
Seasons, Elevations & Activities.
I remember my builder sending different saws to me from sea level
to the same places in the North at opposite seasons. I'm not comparing his tune at sea level to elevation in one season but in many seasons. I possibly tuned 30 saws for myself and others that purchased them. Sometimes the low was the same as his and other times it could be more than half a turn different. Maybe my example dosen't hold much weigh as the weather changes on his end too. Interesting for me anyway. I guess the point is we need to pay attention to obvious and not so obvious changes. Tunning is an ever changing thing.
The 346 had a bad vent but didn't show signs like it was leaning coming of the trigger. It must have been pressuring up and pushing fuel through the primer I assume, giving it the right amount. I figured it was needing more low but eventually figured it on removal of the cap and filter, it was self priming and flooding but hard to detect. I put a vent in and eliminated the bulb.
Good little saw. That was a tough little trouble shoot. Yes more pieces more proplems.
Interesting thread Chris. I enjoy your technical knowledge
Thnx
