351 rebuild

[born to hunt]

I have a husky 351 g that is tired and I’d like it rebuilt. I got it from a guy that does no maintenance and I’m tired of messing with it.
Is it possible to get to to run like my 346xp? What would it take and who to talk to?

 

[Bob Hedgecutter]

Currently uses the same top end as the plastic cased 350- so 353 or 346 topend is where you might want to head to?
Some of the later 350's and Jonsered 2150's had the 353 cylinder on them, but had dished pistons to detune them- so replacing with genuine 353 flat top pistons gave you back to 353 performance.

 

[born to hunt]

Currently uses the same top end as the plastic cased 350- so 353 or 346 topend is where you might want to head to?
Some of the later 350's and Jonsered 2150's had the 353 cylinder on them, but had dished pistons to detune them- so replacing with genuine 353 flat top pistons gave you back to 353 performance.

Thanks! Does any one have the time and skill to take on such a project?

 

[oldguy]

346 top end bolts rite on that saw.

 

[Bob Hedgecutter]

Thanks! Does any one have the time and skill to take on such a project?

Yes- you do. Its not sending a rocket to the moon or Mars- pretty straight forward and fairly basic tooling needed.
Pressure and vacuum test be handy to do before you tear it all down to see if you need new crank seals etc- before you bolt on and fry a new top end.

 

[ChillyB]

Yes- you do. Its not sending a rocket to the moon or Mars- pretty straight forward and fairly basic tooling needed.
Pressure and vacuum test be handy to do before you tear it all down to see if you need new crank seals etc- before you bolt on and fry a new top end.

If I had it down that far I'd just do the seals regardless. I'm understanding that series of saw was known for poor sealing of the adapter base straight from factory, too.

Do I recall that not all adapter bases of that series work for the 346 hybrid? It seems like the 350 is the common one to use. And 340, 345 do not work for some reason.

 

[oldguy]

If I had it down that far I'd just do the seals regardless. I'm understanding that series of saw was known for poor sealing of the adapter base straight from factory, too.

Do I recall that not all adapter bases of that series work for the 346 hybrid? It seems like the 350 is the common one to use. And 340, 345 do not work for some reason.

351 does not have an adapter base, it is the same as as the 346 & 353, the 350 has adapter base.
I have two 351s out in the pole shed, both wearing 346 piston & cylinders.
Also have 7 350s out there, a couple of them are now 346s, love working on 350s, they can be made to roar.

 

[ChillyB]

If I had it down that far I'd just do the seals regardless. I'm understanding that series of saw was known for poor sealing of the adapter base straight from factory, too.

Do I recall that not all adapter bases of that series work for the 346 hybrid? It seems like the 350 is the common one to use. And 340, 345 do not work for some reason.

Disregard a lot if that. I thought this was a plastic clamshell saw like the 350.

 

[RedneckChainsawRepair]

Straight up rebuild. Take any top you want in 346 353 etc. Have fun.

Thats a good one to do with any. Mag cased 351 346 353

Make sure you toss the plastic clamp and go to metal clamp for intake.

 

[born to hunt]

Yes- you do. Its not sending a rocket to the moon or Mars- pretty straight forward and fairly basic tooling needed.
Pressure and vacuum test be handy to do before you tear it all down to see if you need new crank seals etc- before you bolt on and fry a new top end.

I guess it kinda sounds like fun. Can you guys recommend a source for said parts? I’ve been on Baileys and a few other sites. I’ve never put a new cylinder or piston in anything but I have replaced head gaskets on and timing belts on car motors. and I’ve delivered 4 of my own kids which is kinda like sending a rocket to mars.

 

[oldguy]

HL supply

 

[Bob Hedgecutter]

I guess it kinda sounds like fun. Can you guys recommend a source for said parts? I’ve been on Baileys and a few other sites. I’ve never put a new cylinder or piston in anything but I have replaced head gaskets on and timing belts on car motors. and I’ve delivered 4 of my own kids which is kinda like sending a rocket to mars.

Depends on what you want the final outcome to be- you say you already have a 346XP and want the 351 to come close to/be the same- so you go with OEM top end which will be the closest to- but most expensive. You can go OE or the slightly larger bore NE.
Next up is a Meteor or Hyway top end kit- much of a muchness and close to OEM.
After that- its a bit of a crap shoot- you might find kits real cheap- but once fitted they may be no better performance than the old open port 351 cylinder.
There are guys out there can take the cheap cylinders- grind on them and make them perform more like original equipment ones- but if you pay a guy to do it, you spend as much or more than buying an OEM kit for a start.

If you just want to work on a saw and make something that will pull a chain around a bar- aftermarket might see you right for a first build- if you want another 346 hotrod- buy the best you can afford.
Me, I would be replacing main oil seals and all the rubber hoses, check the impulse boot really well and if it still wears the plastic clamp that has not snapped yet- replacing it with a metal clamp meant for an 066 Stihl.

 

[born to hunt]

Depends on what you want the final outcome to be- you say you already have a 346XP and want the 351 to come close to/be the same- so you go with OEM top end which will be the closest to- but most expensive. You can go OE or the slightly larger bore NE.
Next up is a Meteor or Hyway top end kit- much of a muchness and close to OEM.
After that- its a bit of a crap shoot- you might find kits real cheap- but once fitted they may be no better performance than the old open port 351 cylinder.
There are guys out there can take the cheap cylinders- grind on them and make them perform more like original equipment ones- but if you pay a guy to do it, you spend as much or more than buying an OEM kit for a start.

If you just want to work on a saw and make something that will pull a chain around a bar- aftermarket might see you right for a first build- if you want another 346 hotrod- buy the best you can afford.
Me, I would be replacing main oil seals and all the rubber hoses, check the impulse boot really well and if it still wears the plastic clamp that has not snapped yet- replacing it with a metal clamp meant for an 066 Stihl.

Ok. Thanks for the help so far. I got it torn down and the head off. I found an OEM 346xp head for 200 bucks on eBay. I hear guys “deleting the base gasket” and other things. If I want to do this, what should I do for a project saw? I’d like it to run like my xp, but I do not have the experience or a mill to bore anything properly.
Different carb? Exhaust? Any other recommendations?
If this is better in another thread, I apologize!

 

[David Ellis]

Some of the later 350's and Jonsered 2150's had the 353 cylinder on them, but had dished pistons to detune them- so replacing with genuine 353 flat top pistons gave you back to 353 performance.

Both of my inherited 350 Husky's had good cylinders and dished pistons. I replaced the dished OE pistons with Meteor flat top pistons and used moto seal instead of a base gasket. The squish was about .023 ( I think) and the compression is about 150psi. The saws run terrific !

 

[Bob Hedgecutter]

Ok. Thanks for the help so far. I got it torn down and the head off. I found an OEM 346xp head for 200 bucks on eBay. I hear guys “deleting the base gasket” and other things. If I want to do this, what should I do for a project saw? I’d like it to run like my xp, but I do not have the experience or a mill to bore anything properly.
Different carb? Exhaust? Any other recommendations?
If this is better in another thread, I apologize!

Better be new in box and be a complete top end kit for that kind of money?
Yes you can delete the base gasket and use a liquid gasket in place- but do not do so just for doing so- you need to check squish clearances to make sure you can get away with it with your particular new top end of choice.
Plenty of information out there on muffler modifications- choose your own method of execution and once done- make SURE to tune the carb for the new breathability.
You do not need to mill or bore anything on the cylinder- its just a bolt on and go system- good from the factory. Mufflers are a little different if you want to follow to USA standard of boring a hole and welding in a 3/4 to 1 inch pipe for an outlet- can be drilled easy enough with a step drill- welding the pipe in is where the fun begins.

 

[Bob Hedgecutter]

Both of my inherited 350 Husky's had good cylinders and dished pistons. I replaced the dished OE pistons with Meteor flat top pistons and used moto seal instead of a base gasket. The squish was about .023 ( I think) and the compression is about 150psi. The saws run terrific !

Late model (purge valve) 350's should have the 353 cylinder on them from new- the one with the bolt on transfer covers- so if you have that and replace the piston- badda boom badda bang instant 353 on a plastic case- its that easy.

 

[oldguy]

346 oem is the way to fly, you can also put a 357 carb on it, you will need 357 air filter and its mount.
If you do base gasket delete, do you know how to measure squish?
If you have a dremel you can do some grinding that will help.
You are not far from me, I'm a couple miles out of Becker

 

[David Ellis]

Late model (purge valve) 350's should have the 353 cylinder on them from new- the one with the bolt on transfer covers-

I checked my saws and these are the cylinders I have on them.
I don't know that I correctly identified the 353 cylinders when I did my project work, but I vaguely recall finding some other markings that indicated the cylinders were worth using. They do indeed perform well.

For the original poster....

There are several videos about measuring squish using solder in a chainsaw. I didn't really have a favorite among them, but do have a favorite with regard to the general education. I really like Tinman's videos and he has a decent one that explains squish and other things too:

Tinman on Youtube

For me, I didn't want to tinker with a degree wheel so I just deleted the base gasket, measured the squish using a dry assembly. After finding the squish and rotating the assembly I was comfortable with the assembly. THEN, I used moto seal for the base gasket and bolted the cylinder to the base block. The moto seal will add maybe .004 of thickness.

There is no need to "jump" on the OE piston and cylinder from ebay. The cost for a new 346xp OE piston and cylinder is $200 from H L supply:

H L Supply

Oh, also, there is a cultural belief that .020 is a smart and safe squish, but there was some guy who attempted progressively tighter squish until impact happened. I think this was about .012 for his 50cc saw. I think my squish is .017 on one of my saws and it has performed with no impact for a couple years.

I’d like it to run like my xp, but I do not have the experience or a mill to bore anything properly.
Different carb? Exhaust? Any other recommendations?

I did have a friend trim the base block with a mill on one of my saws, but this wasn't necessary really.

Run the same carb.

I recommend removing the screen from the factory muffler and maybe using a dremel burr to open the exhaust hole slightly - with the muffler removed. Bend the hood over the exhaust hole to get better access. Or, you could spend $50 for a bigger hole exhaust on ebay. Leave the screen removed

After re-assembly, check all of the screws after the saw is warm initially then after each heat cycle for maybe 4-5 heat cycles. The muffler bolts have a propensity for coming loose and the cylinder bolts have a propensity for coming loose too.

Oh a personal note, I have always coveted a 346xp, but now that my 350 saws are up and running exceptionally strong, I don't have a super good reason to get a 346xp. I will be interested to read how your project saw progresses and your opinion of the saw when finished. This is especially true since you have a good 346xp for comparison.

So, I suppose a fair summary would be:

Decide on a new piston and maybe new cylinder too.

I kinda recommend checking ring end gap for reasonable space.

Assemble without base gasket and measure squish. (maybe no ring installed in piston and a light coat of oil on cylinder and piston)

Smear the moto seal, assemble with ring in piston and good circlip orientation, and allow to moto seal to rest for a day.

Run it gently a few times. Check screws for tightness.

Open the muffler some.

Tune for maybe 12,500 rpm for the first 1-2 tanks of fuel.

Tune for maybe 13,500 rpm and let us know how it performs !

My thoughts tend to be scattered. Hopefully enough of them make sense and there aren't too many typo's.

Sincerely,

Dave

 

[David Ellis]

Also, about 10 years ago I really did NOT want to learn how to fix chainsaws, but my local shop was taking too long to fix my chainsaw so I started learning. After I got warmed-up to the idea I discovered that chainsaws (Husqvarna for me) are decently well put together, reasonable for maintenance access, and are a fairly inexpensive proposition to repair - IF the saw and parts are fairly common. Your 351 would appear like a great first project.

 

[Bob Hedgecutter]

I checked my saws and these are the cylinders I have on them.
I don't know that I correctly identified the 353 cylinders when I did my project work, but I vaguely recall finding some other markings that indicated the cylinders were worth using. They do indeed perform well.

For the original poster....

There are several videos about measuring squish using solder in a chainsaw. I didn't really have a favorite among them, but do have a favorite with regard to the general education. I really like Tinman's videos and he has a decent one that explains squish and other things too:

Tinman on Youtube

For me, I didn't want to tinker with a degree wheel so I just deleted the base gasket, measured the squish using a dry assembly. After finding the squish and rotating the assembly I was comfortable with the assembly. THEN, I used moto seal for the base gasket and bolted the cylinder to the base block. The moto seal will add maybe .004 of thickness.

There is no need to "jump" on the OE piston and cylinder from ebay. The cost for a new 346xp OE piston and cylinder is $200 from H L supply:

H L Supply

Oh, also, there is a cultural belief that .020 is a smart and safe squish, but there was some guy who attempted progressively tighter squish until impact happened. I think this was about .012 for his 50cc saw. I think my squish is .017 on one of my saws and it has performed with no impact for a couple years.


I did have a friend trim the base block with a mill on one of my saws, but this wasn't necessary really.

Run the same carb.

I recommend removing the screen from the factory muffler and maybe using a dremel burr to open the exhaust hole slightly - with the muffler removed. Bend the hood over the exhaust hole to get better access. Or, you could spend $50 for a bigger hole exhaust on ebay. Leave the screen removed

After re-assembly, check all of the screws after the saw is warm initially then after each heat cycle for maybe 4-5 heat cycles. The muffler bolts have a propensity for coming loose and the cylinder bolts have a propensity for coming loose too.

Oh a personal note, I have always coveted a 346xp, but now that my 350 saws are up and running exceptionally strong, I don't have a super good reason to get a 346xp. I will be interested to read how your project saw progresses and your opinion of the saw when finished. This is especially true since you have a good 346xp for comparison.

So, I suppose a fair summary would be:

Decide on a new piston and maybe new cylinder too.

I kinda recommend checking ring end gap for reasonable space.

Assemble without base gasket and measure squish. (maybe no ring installed in piston and a light coat of oil on cylinder and piston)

Smear the moto seal, assemble with ring in piston and good circlip orientation, and allow to moto seal to rest for a day.

Run it gently a few times. Check screws for tightness.

Open the muffler some.

Tune for maybe 12,500 rpm for the first 1-2 tanks of fuel.

Tune for maybe 13,500 rpm and let us know how it performs !

My thoughts tend to be scattered. Hopefully enough of them make sense and there aren't too many typo's.

Sincerely,

Dave

Most the information you give rings true for plastic 350's- loose mufflers and cylinder bolts- same does not ring true for the magnesium cased 351- indeed the 351 should have the muffler front support bracket from the get go.
20 thou IS safe- no "cultural belief" or urban myth about it, 17 though might be safe, 15 thou might be safe, key word being MIGHT- but a guaranteed safe target is 20 thou.