395XP Carb Mystery

[NoelT]

Rebuilt a 395XP for a guy a couple of months ago.

Since then he's been using it cross cutting logs and it runs beautifully, almost as good as new. Tuned it with tacho after run-in, everything's fine.

Last weekend he used to cut down two trees, on it's side (either side), it runs way rich at low speed and will cut out at idle - not ideal when you're cutting trees 2'+ diameter 100' high and need to use wedges. Saw runs well when in higher revs.

So I tuned it leaner on low and increased idle speed, slightly better but still not good.

Searched this site thoroughly and have asked two Husky mechanics, no help from either. Carb was surgically clean when reassembled and fuel hose & filter, air vent and hose, impulse hose, etc. are all new.

Any suggestions welcome!

 

[albert]

Maybe the metering lever is a bit to high

 

[NoelT]

Maybe the metering lever is a bit to high

I'm thinking around that area, but needle, lever and spring are all new and lever was set level. Will have to dismantle and check there.

 

[joesawer]

Are you sure it is running rich on its side?

 

[wigglesworth]

sounds like the metering lever to me too. They all dont set "level". You need the correct tool.

 

[NoelT]

Are you sure it is running rich on its side?

Yep, it's actually flooding at idle on it's side and takes a few pulls to clear after it's died and set upright.

Lever was set as per WS manual with straight edge, guess that doesn't mean it's still right.

Looks like the carb's coming off

BTW carb is Tillotson HS298A. Saw is 2000 model. My own 395 is 2008 and has the Walbro.

 

[Jacob J.]

Did you set the lever flush with the carb body as described in the Walbro manual? If so, that's way too high for a Tillotson HS carb. The lever is set flush with the recess in the HS carb.

 

[NoelT]

Did you set the lever flush with the carb body as described in the Walbro manual? If so, that's way too high for a Tillotson HS carb. The lever is set flush with the recess in the HS carb.

Damn good point, as the WSM doesn't mention carb type. Lever checked as per attached pic, which also mentions 'too high = too much fuel'. Parts were definitely Tillotson and lever was "right" when installed.

You can be sure I'll be checking that!

 

[oaky]

Did you set the lever flush with the carb body as described in the Walbro manual? If so, that's way too high for a Tillotson HS carb. The lever is set flush with the recess in the HS carb.

howdy jacob, what do you mean about setting the lever flush, then setting in recess.

https://www.ebay.com/p/Zama-Walbro-Diaphragm-Carburetor-Metering-Lever-Adjust-Tools/24003330819
does tillotson have these tools too?

 

[cus_deluxe]

I havent seen one of those for tillotsons, but what he means is that some carbs call for the metering lever to be set flush to the carb body as you look across it. Others have a recessed bowl (like the tillotson in this thread) and the lever should be set flush to the top of that recess. The attached photo (not mine) is a friends hs296, but illustrates the point.

 

[oaky]

okay i get it,
how the heck do you know its still set alright when your lever has to hook into your diaphram like the one picture.
pressure test it?

 

[Chainsaw Jim]

okay i get it,
how the heck do you know its still set alright when your lever has to hook into your diaphram like the one picture.
pressure test it?

The setting don't change when you put it back together. You don't want to remove the metering lever to adjust it. Lightly lift up on the hook end if it's too low, or lightly hold the other side of it down while you push the hook end down if it's too high. The metering lever is aluminum and bends very easily, so leaving it in place when adjusting it will help prevent mangling it all up.

 

[oaky]

have you guys ever had to bend a brand new lever

 

[ncfarmboy]

Yes but not often.
Shep