346xp Scored Piston

[Mtnyota]

Hey guys just found out my saw is in poor shape and need some pointers/advice.

I bought a used 346xp NE in very clean condition. I checked the piston at time of purchase and is was nice and smooth. The saw looked almost brand new. I brought it home and mixed up one gallon of gas with the Husky synthetic oil 2.6 oz bottle. I ran 4 tank fulls and then the saw would die after I finished a cut. After it died I would be unable to start it for a few mins. After a few minutes it would start but die again after the cut.

I pulled the covers off the clean everything up and see if anything looked suspect. Upon pulling the muffler I found the scored piston.

I'm assuming this means the saw ran lean? It would fourstroke out of the cut but not in the cut. What else should I look for before I tear it down/order parts.

Thanks for the help.

 

[Rokon]

OUCH!

Tear it down to check cylinder and other parts. Bare minimum is piston and rings IMO.

 

[Ctd01]

Ouch x2! I was guna ask if you had an air leak but i see that you said it was four strokin . Plastic intake clamp was an issue on that saw. Mine had a loose cyl something to check.

 

[Mtnyota]

It's my understanding that scoring is caused by insufficient or no oil, running lean, or debris from insufficient air filtering. Is there any causes I could be missing?

Where is a good place to get piston/cylinder combo?

 

[nmurph]

Pull the cylinder and let's have a look. I have seen cylinders where the piston looked worse than your's clean up.

I bet that what you thought was four-stroking was in fact it hitting the limiter.

You pretty much named the causes.

 

[ndlawrence]

It's my understanding that scoring is caused by insufficient or no oil, running lean, or debris from insufficient air filtering. Is there any causes I could be missing?

Where is a good place to get piston/cylinder combo?

yes that is correct, what he is saying is that you can be running lean if you have an airleak such as bad seals, loose cylinder, ect...

OEM cylinders are best but you'll have to pay a pretty penny for them

 

[Mtnyota]

Ok tomorrow I'll pull it apart and look for any sources of air leaks.

As for the tuning, I could have been hearing the rev limiter. I guess I need to spend more time learing how to tune the carb.

Is bailey's the best source for pistons and cylinders?

 

[Ctd01]

I like baileysy

 

[SawTroll]

Hey guys just found out my saw is in poor shape and need some pointers/advice.

I bought a used 346xp NE in very clean condition. I checked the piston at time of purchase and is was nice and smooth. The saw looked almost brand new. I brought it home and mixed up one gallon of gas with the Husky synthetic oil 2.6 oz bottle. I ran 4 tank fulls and then the saw would die after I finished a cut. After it died I would be unable to start it for a few mins. After a few minutes it would start but die again after the cut.

I pulled the covers off the clean everything up and see if anything looked suspect. Upon pulling the muffler I found the scored piston.

I'm assuming this means the saw ran lean? It would fourstroke out of the cut but not in the cut. What else should I look for before I tear it down/order parts.

Thanks for the help.

It likely ran lean, at the limiter, out of wood - a tach would have revealed that! :msp_wink:

 

[Mtnyota]

Ok I've been researching tuning, but with the 346xp do I have to buy a unlimited coil, then tune it until it only fourstrokes a little after the cut.

 

[nmurph]

You have two options: buy a tach and use the current coil, and then tune it to the factory spec maximum: replace the limited coil with an unlimited coil and tune for a four-stroke. I like the second choice as it then allows a muff mod to be done without the need to retune in the wood. A MM really changes the attitude of these saws.

 

[CentaurG2]

Looks like she was running a little hot. Pick up the senDEC 5000 tach while you are ordering parts at baileys. You can use it to check your saws or just about anything else. My ne346xp is limited to 14100k. I set mine at 13900-14000k and forget about it. I usually will re-tach when I clean and change the air filter or make a switch in fuel mix. Knock on wood, I have not cooked a saw yet. As a side note, you might be better off selling your saw on ebay and using the proceeds to purchase another. The 346xp is very popular and even ½ dead, it should fetch good money. It might save you some time and aggravation. Good luck.

 

[sunfish]

Ok tomorrow I'll pull it apart and look for any sources of air leaks.

As for the tuning, I could have been hearing the rev limiter. I guess I need to spend more time learing how to tune the carb.

Is bailey's the best source for pistons and cylinders?

Like nmurph said, you probably do not need a new cylinder. Usually the cylinder can be cleaned up and just a new piston and ring installed.

I like to get parts from my local Husky dealer, they stock a lot and their prices are cheaper than any I've found on the internet. But Bailey's is a good place to order from.

How much 'tuning' did you do before ya roached it?

 

[Mtnyota]

I have heard about people using muratic acid to remove the transfered aluminum, and then sanding with like 600 grit. Are there any other tricks to cleaning up the cylinder?

 

[jus2fat]

Yep..that's the way you do it..!!

Heating the cylinder will help the muriatic acid work a bit better..!!

J2F

 

[belgian]

I have heard about people using muratic acid to remove the transfered aluminum, and then sanding with like 600 grit. Are there any other tricks to cleaning up the cylinder?

That scoring is pretty bad, and I doubt you will be able to save the cylinder. Can't tell really without pulling the jug of course.
For a fairly new model, I'd go with a new P/C and tune it right.

 

[Mtnyota]

I'm trying to do a vacuum and pressure test to determine if the saw had air leaks or if it was just running way to lean. The problem i'm having is the intake is setup different on my saw compare to the saw pictured in the "poormans vacuum test" thread. I'm assuming the the tube the runs under the intake boot is the impulse line. If that is the case I would assume I need to cap the nipple that connects to the boot and then make a seal between the carb and intake boot?

 

[SkippyKtm]

I'm trying to do a vacuum and pressure test to determine if the saw had air leaks or if it was just running way to lean. The problem i'm having is the intake is setup different on my saw compare to the saw pictured in the "poormans vacuum test" thread. I'm assuming the the tube the runs under the intake boot is the impulse line. If that is the case I would assume I need to cap the nipple that connects to the boot and then make a seal between the carb and intake boot?

You could do it that way, but another way to do it is this:

LINK

 

[Mtnyota]

Got it thanks.

 

[Mtnyota]

I think I lucked out. The cylinder in my newbie opinion looks like it should be fine. Ive still have some transfered alum to removed, but I think it should be good. I plan on getting the meteor piston kit and putting it back together. Is there anything else I should order/replace while I'm in there? I ordered a tach and I'm thinking about an unlimited coil.