346XP. "H" screw all the way in and only ~11,000 RPM, no load. Need some serious tuning advise!

[rustyb]

My coil is blue and stamped 14,100. So, I thought I'd set the RPM at 14,000 with the tach and go from there.

I warmed it up first by cutting for a few mins. I knew it was rich. I then tached it and she was around 8000 RPM, no load on the bench. So I kept turning it in, 1/4 turn at a time, checking the RPM with each turn. I did this until.....until it wouldn't turn any more....and it was only turning in the 11000 range....perhaps 12000. The screw was all the way in! I don't recall exact numbers but I do know it never hit 13000.

Knowing something wasn't right, I backed the H screw out about 3/4 of a turn and started cutting wood. Honestly, this saw had never cut so good and so fast. After a bit though, it began acting like it was running out of gas....even on a full tank. Thinking that was due to being too lean, I backed the H screw out ~1/4 turn and started cutting again. No problems after that. Saw runs really, really good.

I didn't tach it....but I did shut it down while wide open in the cut....then I pulled the plug. Please see the attached photos. ALSO, for what it's worth, I looked in the plug hole with a flash light....and the piston top is covered with black stuff......except for a small section that would be towards the air filter side....and that was just bare metal.

Can anyone tell me what's going on.....besides of course that I don't know what in the hell I'm doing?

Saw may have had the limiter caps cut off and it may have had the muffler opened up.

 

[backhoelover]

is you muffler starting to clog also them coil has stages in them if the last stage start to go bad it will drop rpm when it get to operating temp. i had a saw do the same thing one time

 

[sunfish]

Sounds like a carb problem. Put a kit in it and see.

 

[JonCraig]

Anything recently done to saw? i.e., what made you tune it? Just finished rebuilding? Or just picked it up off the shelf after 6 months? Or?

 

[o8f150]

I agree with sun,, put a kit in the carb

 

[rustyb]

This saw has probably cut fewer than 4 cords of wood....perhaps as little as 3 or even less. Can't imagine it needing a carb kit or new coil.

When I got the saw, I tuned it in the wood....while cutting. It seemed such a pain that I didn't touch it after that. I then took it to a higher elevation so fattened it up a bit. Being that I alternate between cutting at 3500' and 6000', I just decided to get a tach due to thinking it would be so much easier to tune properly.

 

[old guy]

I have 2 346oe's that were like that, carb kit cured em both.

John

 

[HuskStihl]

346's are well known to not be very rev happy saws. 11k sounds about right to me

 

[old guy]

Mine are turning 14,600 now. The book says 14.700.

John

 

[PULLINmyPOULAN]

Sure the choke rod was all the way in or stuck half way sometimes it happens.It will run pig rich with the choke rod out a little.

 

[PULLINmyPOULAN]

Zama EL32 carb kit RB-122

 

[Landmark]

If available I would try a different coil and rule that out first.

 

[rustyb]

Thanks for the replies, everyone.

What about the plug though? I thought it looked pretty good....or is reading the plug in a saw not a great indicator?

Also, what about it acting like it was running out of gas and then being cured after fattening the H screw? Isn't that a sign it was too lean?

Lastly, I'm using a cheap tach. Could it be that it's not my saw after all but a bad tach reading?

It just seems to me that a saw with that little time on it shouldn't need a carb rebuild or coil. But.....maybe I'm fool'n myself.

 

[Big_Wood]

is this saw a virgin or has a hack been in it? the plug is showing it is running rich. if it only tachs to 11k this is the reason. i don't believe a kit is going to help this carb at all although if the running out of gas symptom happened after a bit of running i would certainly vacuum test the tank to be sure the vent is working. it sounds to me like your metering lever is set to high overfeeding the needles. i recently had an issue where an OE i ported wouldn't tach over 14k with the high speed closed. removed fixed jet, soldered closed and drilled smaller. have it tached to 14.7k now at half turn of the H screw. tachs out to 16k with very light 4 stroking with the needle damn near closed. this won't be the case with yours though. i'd pull carb and make sure it is assembled correctly before anything else.

 

[Chainsaw Jim]

Make sure the air filter is clean enough to be brand new, and put a new fuel filter on it. Carb kit is always good as mentioned above.

 

[Chainsaw Jim]

Saw may have had the limiter caps cut off

Are you positive the caps are completely gone? I hate to ask this stupid question but you used the words may have.

 

[Tor R]

is this saw a virgin or has a hack been in it? the plug is showing it is running rich. if it only tachs to 11k this is the reason. i don't believe a kit is going to help this carb at all although if the running out of gas symptom happened after a bit of running i would certainly vacuum test the tank to be sure the vent is working. it sounds to me like your metering lever is set to high overfeeding the needles. i recently had an issue where an OE i ported wouldn't tach over 14k with the high speed closed. removed fixed jet, soldered closed and drilled smaller. have it tached to 14.7k now at half turn of the H screw. tachs out to 16k with very light 4 stroking with the needle damn near closed. this won't be the case with yours though. i'd pull carb and make sure it is assembled correctly before anything else.

I have exactly the same issue with one of my owm 242. Suddently it went superrich, from 1 turn to 1/4 turn on H needle. Did a full carb rebuild pluss exchanging and adjusting the metering lever. Waiting for å few parts before I can test it again.

 

[rustyb]

Thanks for the replies, everyone.

To answer your questions:

I washed the filter in soapy water about 30 mins cutting time before taching it....and I blew it out right before putting the tach on it. The filter was clean.

The limiter tabs are not on the saw.

The choke was fully open.

The saw is a virgin....outside of the carb limiter tabs/ears being removed and the stock opening in the stock muffler being opened a little.

I have not checked the fuel filter. I will say though that I am anal about keeping stuff out of my gas, gas can, gas tank.

One thing I forgot to mention: Before it started acting like it was running out of gas, it would stumble a bit upon throttling it.

ALSO, I noticed it acting like it was running out of gas when cutting sideways. Don't recall it acting the same when cutting uprigh.

The fuel tank vent: I haven't checked it. Could it be partially plugged/covered with sawdust?

 

[Cliff R]

It's just about impossible to tune a saw reading the plug. ALWAYS tune for best power in the cut by starting out just a tad rich and sneaking up on the ideal setting. Limited coils can make the process a bit difficult as some will mimic the 4-stroking when the load is removed that indicates we don't have the carb set too lean.

I also 3rd of 4th the recommendation to put a kit in the carb and thorough cleaning while you are in there. This new fuel has a bad habit of plugging things up, even on low hour saws. I do this for a living and get to see it every single day!.....Cliff

 

[rustyb]

It's just about impossible to tune a saw reading the plug. ALWAYS tune for best power in the cut by starting out just a tad rich and sneaking up on the ideal setting. Limited coils can make the process a bit difficult as some will mimic the 4-stroking when the load is removed that indicates we don't have the carb set too lean.

I also 3rd of 4th the recommendation to put a kit in the carb and thorough cleaning while you are in there. This new fuel has a bad habit of plugging things up, even on low hour saws. I do this for a living and get to see it every single day!.....Cliff

Thanks. I was just looking at the plug to see if it offered any clues as to what was going on. Was using the tach to tune followed by a fine tuning in the wood. But I never made it that far...

Is it possible the fuel tank vent could be playing a factor? I would like to eliminate things like that before messing with a carb kit.