Stihl 026 Walbro WT - Help - Metering Lever Questions

[Hoggwood]

Hi Folks,

Please advise if this post is in the wrong area.

Relatively inexperienced here. I read a lot and try to make up for my lack of knowledge.

Bottom line: In short, with this carb set-up what are the corresponding metering lever height w.r.t. the bosses in the chamber floor and final L and H settings to maximize torque for this saw.

Story: I picked up an 026 pulled the carb, cleaned it up, new kit, fuel line/filter, plug, air filter, some av buffers, removed, cleaned and reset coil (gap). Impulse line sound. Pulled the muffler and inspected piston (very clean trace of machine marks still present). When I put it all together, I noticed the metering leaver arm was flush with the (I guess you would call them) bosses in the floor of the metering chamber. I assumed this was correct. I have set other carbs flush with the outer edge using steel rule (ie HDB) with no problems. I set the L and H mixture needles at 1 turns out per sticker on the cover of saw. The saw fired up and ran. There is no evidence of air leaks (steady idle and the saw maintains rpm regardless of orientation).

I let the saw warm up, adjusted the L a bit richer approx. 1 1/4 for nice acceleration and left H at 1. Hit the bush and buried it in a log to tune it further. Now this is my first modern higher reving saw, but it struggled. Let's just say a 3400 and a 452vl that I serviced and had on hand as well stomped it. I found after several cuts and adjustments on the H, I was needing to be < 3/4 to get the saw to power through cuts with some degree of authority ( 16" 0.375 b&c in 16" + Douglas Fir). The saw certainly began to wake up when I leaned it out but I stopped at 3/4. I have not willingly advanced to cleaning up scored pistons and cylinders yet.

I am not entirely sure how close to two stroking at WOT that saw should be running out of the cut and how far into four stroking in the cut. I don't have a tach and it is much easier for me by ear to discern the subtle (distinct) sound of the older lower reving saws just cleaning up (and staying clean) in the cut under load and immediately four stroking when lifted off. If the lever height is in fact correct I don't know if it should be optimized at one turn on the H or if the general practice is to lean it out from there.

I pulled the carb as I figured it must be metering rich. I saw this post...

http://www.arboristsite.com/community/threads/walbro-wt-metering-lever-adjust-info-please.177248/

Am I to understand that the meter is to be set 0.06 - 0.07 BELOW the bosses in the chamber floor? The carb does not have the circuit plate like the HDB I am familiar with. I don't have the Walbro tool and have set other carbs a bit lower 0.02" below if they run fat. Perhaps the nub on the new diaphragm is slightly longer and is pushing the lever further than it should?

I just want to get this one ripping.

Thanks in advance - Cory

 

[nmurph]

It is set from the top of the carb body, not from the floor.

 

[watsonr]

here is the WT manual. It describes how to set it up.

 

[Hoggwood]

Thanks, I had referred to the manual previously and should have stated so. The manual describes using the Walbro gauge tool. Is the tool sitting 0.06-0.07" lower in the middle on the WT alignment? Would this then just make it flush with the inner bosses standing off of the chamber floor ( don't have the tool).
In addition, the manual had stated to adjust the H to a "smooth two stroke then back of until it just four strokes". The 026 manual avoids giving any minimum turns setting on the H and only walks through the L setting.
So how far in (beyond the 1 turn displayed on the sticker on the filter cover) is it safe to go in fairly low elevations?
Walbro settings defer to Stihl and Stihl says nothing beyond 1 turn out on the H?
Perhaps this carb is inherently way over rich at standard height and turns.

 

[nmurph]

A metering lever set too high will make the saw run rich.

 

[watsonr]

Set the lever flush with the floor or just barely above as the manual show. It should run correctly. I set mine flush, also means that the H needle needs to be a little richer than the called for one turn. You want it to 4 stroke out of the cut at high RPM and 2 stroke when in the wood.

The tool is just barely above flush.

 

[Hoggwood]

Thanks guys,

Defective new air filter. I discovered upon close inspection, and only after the filter began to collect sufficient dust, that 60+ % of the material was clogged with glue. I could only tell after the filter began to collect dust in certain spots where it was pulling air through and not in (a lot) others where there was glue impregnated into the fabric.
I couldn't see it on the new filter. No wonder it was ultra rich and I was compensating by leaning it out. I feel stupid but I couldn't tell that filter was clogged right from the factory.

With the lever set just below those bosses and wearing the old worn OEM filter the saw is running as it should.

That is aftermarket for you.