346 OE intermittent bog, won't reach 13k RPM, Revisited FIXED!!!

[sunfish]

Going on the back burner until I get a new carb mounting flange, screw is starting to strip out, and I managed to break a starter pawl.

I've had a warped carb flange and another striped out, both from over tightening. They don't need to be as tight as most folks get em.

Have had two saws act like yours and both times was a bad carb, one a Zama & one a Walbro. Brand new carb fixed both. Not saying that's the issue here, but most times a new carb is better than putting a kit in one.

 

[Sty57]

Older saws often have more compression do to buildup in the top end, which artificially raises compression a bit. Oil buildup can drastically increase compression as well, so I run the saw tuned crisp in the cut shut the saw off, let it cool down and take a reading. Saws that idle a lot or rich will give you higher readings. This series of saws has been all over the place when it come to things like this, and is one reason you can get a dog out of the box or a real runner. My personal 346 had 145psi before I remove the base gasket, it's now around 160 with .016" squish and is the best example of an otherwise stock 346 I have ever ran.

Anyway all these things can add up to giving us slightly different readings, my point was compression is likely not the issue here.[emoji6]

I fully agree with you.
And don't forget altitude of the user changes the reading also.

 

[Sty57]

Have you checked to make sure the throttle linkage is not binding and is going fully open?
Make sure the plastic piece on the tank side of the linkage is not worn or broken.

You said this was built from boxes of parts.
You sure the linkage isn't from a 359/357?

 

[decableguy2000]

Pulled this one back off shelf this week-end to start over. Awhile back I ordered a new intake boot, and carb base. I'm waiting on a gasket at the dealer to pick up before I get it back together. I did find this though. I know more this weekend

 

[redlight066]

Where in WNC are you? I'm about 25 minutes south of Hendersonville. I'd be happy to put a fresh set of eyes on it for you. I'll be home all weekend. Let me know if I can help. Rich

 

[malk315]

Subbed. Hope you get this sorted!

 

[decableguy2000]

Finally got all my parts in and I'm starting over.
NEW OEM base gasket
New Metor piston and rings (had one sitting on the shelf for a year or so)
New carburetor base
New intake
New style flange with a 390 clamp as the snap clamps hate me
New OEM fuel line and filter
New spark plug
Carburetor was new when I started this journey

Got it together and it still runs like crap.
I'm letting it cool off, and I'm going to start trouble shooting over.
FUEL is good 93 E-free 40:1 with Stihl ultra (works fine in all my other equipment)

Step
1. ????
2. ????
3. ????
4. ????
5. Sell it for beer money

 

[beaglebriar]

What exactly is it doing? Have you tried a coil swap?

 

[decableguy2000]

I had some progress and a set back on this today.
Started over with pressure and vacuum tested the tank to make sure the tank vent and filter are not clogged. PASSED
Pulled the carb off and opened it up, checked metering lever. Looks new inside and lever set flush.
Now I found a *pretty boy moment. Being a new carb it didnt have the limit cabs installed I thought I had the high and low screws in all the way and backed off 1. However I had them out about 2 1/2.

New symptoms
Wont idle unless you hold the throttle open slightly, and the throttle screw is all the way in
will reach 13.7K at 7/8 turns from bottom

I marked the carburetor this time so I can swap them with the one on my 351 and see if there is a difference.

 

[decableguy2000]

Who ever said it was something simple and overlooked is the winner.

The new carburetor was on the 351 marked it with a N.
I think I must of mixed up stuff trying things back and forth. In the the process I stripped the carb base on the OE 346, which also had the bad intake boot.