Hello,
I have an 028AV Super wood boss. Last week it died while cutting a log. It would start back up, idle, run wide open, then die while cutting again. I have since replaced the carburetor, fuel line, fuel filter, impulse line, plug, and cleaned the exhaust screen. I have also mixed brand new fuel. Same problem persists. I did notice I was able to make a full cut with the choke partially open but it wouldn’t rev all the way up. Closed the choke and after about 20 sec it died again. It doesn’t putter and die, it shuts right down. I suspect some kind of fuel issue but I’m far from a small engine guy. Basically living and dying by YouTube at this point…. Any help is appreciated.
You have a lean fuel condition but suspect have figured that much out. Choke trick & repairs direction.
You have large displacement 028 Super. Nice.
To be safe do a Leak Test. Id. an underlying issue.
Ime, the 028 wants extra High screw richening. If setting carb on a Tach then probably too lean at WOT. Specs on 028 are 12500 rpm but I've found 10800 to 11200 to perform best on an 028 AV (43cc) with 18" .325 chain.
... also found Tillotson HU carb version is very sensitive to adjustment. Do small changes per iteration, 1/16 turn.
... suggest try to tune WOT heavy 4-stroking. Plenty rich no load WOT (CCW on High). Should pull entire cut even pig rich with more speed than choke override.
... slowly lean out High (CW) until exhaust tone cleans up in cut & rips properly. Out of cut it should remain rich & heavy 4-stroke. Probably not 12000 - 12500. Aim lower WOT, 11500 max.
... 028 exhaust will bark beautiful when get it right, fat & blubbery entering cut, then clean-up & howl pulling chips.
... if still stalls in cut, give it more High screw (CCW). You might need extra fuel due to large log cuts > 20 seconds Retune later for smaller stuff.
Other things to investigate
1. So first please save your original carb. Probably a Walbro on 028 Super. Worth cleaning & rebuilding versus installed cheapo aftermarket carb. Should cost only $20 for a kit.
-- K10-WAT diaphragm kit or K20-WAT rebuild kit for 028 with Walbro WT-16 carb.
-- RK-14HU for 028 with Tillotson HU-40 carb
2. Carb metering lever setting. Fyi, I've experienced poor results in 028AV when raising lever. Just put to factory height setting or high side of it. Thinking flush to carb body for WT or HU. Back to (1).. worthwhile to rebuild OE carb. Unknown aftermarket quality & tunability.
3. What is condition of the Intake Boot at carb flange. Is there the proper aluminum spacer, inside ring sleeve, & a proud boot flange. Ensure carb compressing a good seal here. I've witnessed boot flange ("donut") that hard & compression set to point of bad sealing & lean air leak.
... OE Intake Boot are NLA (1118 141 2200), used on Ebay, various quality of aftermarket & Proline #37-1008. Many choices.
4. Doubt it as description but check fuel vent. Stubby vertical hose on left of carb into tank. Should be the drub screw type. Can pull off from tank nipple, confirm nipple open into tank, the test run as free open vent. But, venting issues usually exhibit after several minutes fuel consumption vs 20 seconds in cut.
