350 fixer upper

[gsxblaze]

Hey all, my brother gave me an old "parts saw" he's had sitting in my father's Barn for probably 15 years now. It was missing bar and chain, clutch cover, top cover in a few parts on the carburetor. It was given to him years before that for parts for his old saw but he never touched it.

Dumped a little gas in the carburetor and I was able to get it to start for a second so I decided I would try to see if I could get the old saw going again. Ordered all the new covers, bar and chain and a new carburetor for it and I have it all installed but I still can't seem to get it to start. The fuel line was missing so I put a new fuel line with new filter when I did the carburetor as well. I'm not sure if it's just something in the adjustments or what but it doesn't seem to be getting fuel. If I dump gas down the carburetor I can get it to start, then it dies. Can't run it at all without the choke on. And even still it only runs as long as that gas that I dump in the carburetor is there. I've checked the fuel line to make sure fuel can flow and it can no problem, feel like I'm missing some stupid little thing ,any thoughts?

 

[gsxblaze]

Another thing to add is I know the carb will need adjustment, it just screams wide open when I am able to get it started, so maybe it's all in the adjustments?

 

[Bob Hedgecutter]

Start, scream, die = massive air leak usually.

 

[david newbie]

I just ebayed one (350) that idles way!!!!!! high and I thought it was probably an ear leak

 

[gsxblaze]

After posting I noticed the impulse line was rough, replaced that with a piece of fuel line and I can now start it/idle with choke on, then when I shut the choke off it'll rev/run for a few seconds before dying out. So some progress made. Going to try adjusting the idle screw now that I can start it, maybe the new cheap Amazon carb needs some fiddling

 

[J D]

I'd start by pulling the muffler & inspect the piston so you know its not scored. Then set the carb to the initial (1 turn out I think) setting. If it doesn't run within 1/2 a turn of that there's probably something wrong that needs addressing or you risk seriously damaging the saw.
To complicate things slightly, Chinese carbs sometimes don't match the factory carb for initial adjustment.
Check your impulse tube, the original one was made out of coiled hose to make the tight bend it needs to... if you have used regular fuel line it may be kinked or flattened restricting impulse.
Next thing to do would be a leak test.

 

[NSEric]

Check the intake boot clamp by the cylinder, they're known to break and leak.

 

[Chevboy0167]

May wanna take a look at the intake boot if saw looks like it had been abused or run hard and put away wet often. Overheating can melt the impulse passage causing weak or no fuel pumping issues. I see this on many of the beat down 350s I rebuilt. This will cause a lean condition as well as the junk plastic intake boot clamp that can snap.

 

[Jasonrkba]

As others said the intake boot. There is an upgrade for this. Buy a rebuild kit for the oem carburetor and put it back in.

 

[Bob Hedgecutter]

Intake manifolds, main seals, warped cylinder riser, loose pan bolts- lots of places a 350 can suck stray air.
Twas a parts saw/wreck for a reason, rather than replace the missing bits and calling it good- time for a total rebuild and a genuine carb if you can find one.

 

[gsxblaze]

Decided to dig into it a bit further, pulled the cylinder and she's definitely a bit scruffy in there, and cylinder gasket was pretty much non existent as well.

Time to rebuild maybe, 346 top end maybe? If I'm going to replace things I might as well upgrade while in there. Thoughts?

 

[quattro.pilot]

Can-O-worms there mate! There's definitely multiple problems going on with that saw.... going to take a bunch of investigation.

OR

You can just throw money & parts at it by replacing everything possible and the end result should be you have something that runs properly.

I guess since you got it for free option2 isn't the worst idea. However it's nice not to be too indebted to a chainsaw or R&R things that didn't need it.

First things first I would ditch that Amazon carb and start looking for a Walbro replacement.... I'm sure you can find one used...plan on a rebuild kit and if you can get it into a ultrasonic cleaner all the better. There's no use in throwing $200 in parts and hours of your time into the thing if at the end of it all you still struggle to tune it because of a piece of **** carb.

If you want/need to be cost-conscious then while you search for a carb I would start doing the following:

2. You need to find bottom end leaks. Get a new base gasket, clean up the case and cylinder surfaces, then install the original cylinder...piston not needed. Use a hose clamp in place of the original plastic intake clamp and reinstall the intake boot. Block of intake and exhaust ports. Install a spark plug. Plug the decomp hole, OR, clean the decop valve really well and install with thread sealant just to be sure it's not a source of leak. You'll want to pull the flywheel as well as clutch & oil pump in order to expose those seals. Do pressure test

This is a quick & dirty setup for leak checking the important stuff. The case is essentially sealed and you have access to observe leaks at all of the major points. Husqvarna pressure spec is 0.8bar with leakdown no lower than 0.5 (or 0.6 depending on rig) in 30seconds. Vacuum has no spec but whatever you feel is reasonable. Replace seals or dress surfaces as necessary


3. Plan to replace the following intake parts: Clamp (updated), Rubber boot, and Plastic "hanger"

4. Replace the "curly" fuel hose line..... just good preventative....and new fuel lines are sooooo nice . Or don't, up to you, but I'd inspect or otherwise pressure-test it and the tank. Impulse line should be good....they're so short they rarely have any issues

5. 346xp hardware is a direct bolt on. Often sales on new oem P&C kits. reuse your long cylinder head bolts. Tons of info available on the conversion as I'm sure you're already aware.


You have a fun project on your hands my friend.... it's all pretty easy to arrive at a happy ending lol .. just takes time more than anything, and as I said above it's very easy to get carried away buying new parts. If you can't spend a lot of money then more trouble needs to be taken in order to eliminate parts that don't need replacing. For sure the carb though....cheers

-Rob

 

[J D]

Impulse line should be good....they're so short they rarely have any issues

I've had 2 that had pin holes in the impulse line, one of them really did my head in

 

[quattro.pilot]

I've had 2 that had pin holes in the impulse line, one of them really did my head in

oh no, that would be bad yes. thanks for weighing in as I haven't come across bad impulse lines yet. It's definitely worth removing and scrutinizing then

 

[Chevboy0167]

An OEM 346 cylinder will have to be modified to properly run on the 350 bottom end. There is no crankcase impulse hole in the cylinder riser. The same goes for aftermarket "big bore" cylinder kits. I fully rebuilt 3 last summer. 2 with aftermarket big bore and 1 with OEM 346XP OE kit.

Ya gotta drill a hole through the cylinder and grind out an impulse channel or try to drill a hole through the riser at an angle to gain crankcase impulse. I chose to drill and grind. And used sealant to plug the stock hole in the cylinder base.

Stock 350...




New OEM and big bore...

 

[markle]

An OEM 346 cylinder will have to be modified to properly run on the 350 bottom end. There is no crankcase impulse hole in the cylinder riser. The same goes for aftermarket "big bore" cylinder kits. I fully rebuilt 3 last summer. 2 with aftermarket big bore and 1 with OEM 346XP OE kit.

Ya gotta drill a hole through the cylinder and grind out an impulse channel or try to drill a hole through the riser at an angle to gain crankcase impulse. I chose to drill and grind. And used sealant to plug the stock hole in the cylinder base.

Hmmmm…this is interesting about the impulse channel mod…and I didn’t even bother to check. I just put a meteor big bore P/C kit on a 350 (Meteor advertises it for 346/350). Also added the improved intake boot with metal clamp (this was the source of the massive air leak that cooked the piston), crank bearings and seals were fine, but a pressure test showed the sealant btwn plastic crankcase and metal riser leaked at the clutch-side joining surfaces ( no stock gasket here, just sealant)…resealed…passed pressure and vacuum test….now this saw runs wicked good. So, where might it be getting adequate impulse from since I didn’t modify the meteor cylinder as you say chevyboy? Not doubting you…maybe some 350s had the impulse channel in the riser? Flummoxed………..

 

[Chevboy0167]

Yeah, the cyl riser is usually deformed to the plastic bottom end when the factory torques down the bolts. I sand both sides down with 600 grit on a granite flat block in a non-directional pattern. Then seal up with Motoseal or Yamabond 4. No leaks yet!

I too put a big bore Meteor kit on 1 saw here. If I remember correctly, the hole in the cyl base was sitting just near the edge of the riser but still blocked off. Another saw got a Hyway Titanikel top end that was the same deal.

Hmmmmm.... about the impulse on yours..... maybe the hole in the cyl base is sitting halfway open on the top end u got? I dunno? Got the part number on the top end kit U used?

 

[huskihl]

Piston is on backwards to start. If they’d do that, it’s hard to say what else could be causing issues

 

[Chevboy0167]

Son of a........ . Good catch huskihl! I must have my blinders on..... sheesh!

 

[markle]

The Meteor kit shown in the image. I’m tempted to pull the cylinder to verify, as you guys know it’s not that bad of a task. Apologies if it seems I hijacked this thread from gsx’, but it is all relevant to his rebuild of the 350….how’s it going?