How to tune 346xp

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

livemusic

ArboristSite Operative
Joined
Apr 13, 2012
Messages
248
Reaction score
139
Location
Louisiana, USA
Modded, ported 346xpne, and I was told it has a larger Walbro HDA199 carb... finally getting to use it after a long down time. Long story but it hasn't been used in a few years and I would just crank it several times a year and run it a minute or so to, hopefully, keep it functional. Now, after (hopefully) getting it all fixed up and now cutting with it some, it dies often at idle. (It runs great otherwise.) Using 40:1 mix with Echo Red Armour oil. It has a tach onboard and when I first started using it recently, it was idling around 3500 but I note it has since varied between 2500 and 3600. What exactly should I do to tune for idle so it doesn't die? And what high rpm to tune to? (When it dies, I have to then choke it and it hits one time and then I turn choke off and it will crank in a pull or two. This is even with a warm saw.) TIA!
 
Sounds like there's not enough inertia in the intake air column for fuel vapor to become and/or remain suspended when the intake port is closed by the piston descending. If this is so, it may not idle smoothly at less than 4000rpm.
Do you still have the standard carb to try?
 
That idle speed should be enough to keep it running. I believe book is 2700. WBF advice is cheap and easy to try. If it has never been re-built it could still have the blue pump diaphragm. These stiffened up very quickly and most saws they were used on don't have a strong enough impulse signal to draw fuel at idle.
 
How do you soak a carb, what does that mean? Remove it and soak in something? What?
Out of curiosity, do you use ethanol free gas in your 40:1 mix or E10/E15 gas with ethanol? If so, start using ethanol free gas if you're going to operate the saw like you've described (periods of sitting without use).

If you aren't familiar with carb cleaning and rebuilding you're going to probably want to watch some of the numerous videos on Youtube which show the procedure. In fact, I believe Walbro themselves have a video series that show proper disassembly and reassembly.

Get yourself a fresh Walbro gasket kit, disassemble carefully, soak and spray the carb in the appropriate carb cleaner, clean all ports, blow out all passages and put it back together retaining your current carb settings. Throw a fresh fuel filter in there as well and confirm no leaks or issues with the fuel line. Once you get it running you can tune it appropriately.

Good luck!
 
Thanks, I do use e-free gasoline. The saw runs great except for this issue. I just ran it again and this time, I would get it cranked again with no choke on, just pull without choke until it started. I wonder if it will just slowly improve on its own, lol. I wish there were an additive one could add to make it do right! Actually, I have had luck with Sea Foam with other motors, wonder if that help. Hey... Mechanic In A Bottle!
 
Thanks, I do use e-free gasoline. The saw runs great except for this issue. I just ran it again and this time, I would get it cranked again with no choke on, just pull without choke until it started. I wonder if it will just slowly improve on its own, lol. I wish there were an additive one could add to make it do right! Actually, I have had luck with Sea Foam with other motors, wonder if that help. Hey... Mechanic In A Bottle!
Unfortunately, no amount of mechanic in a bottle will solve a hardened metering diaphragm or a cracked fuel line. Gummed up needles and passages aren't always the problem.

A carb kit is probably $20 and should be done anyway if the carb hasn't been rebuilt in the past ten years.
 
Back
Top