mystery saw, blue smoke screen

[Oldtoolsnewproblems]

got a mucholloch 320 from the trash the other day. it popped when i pulled the cord the second time with a little gas down the carb, but nearly blew out my eardrums. thats when i realized the muffler was fully removed. so i did a partial tear down and cleanup, helicoiled the stripped exhaust studs and a few other mounts, new fuel pickup and vac test was perfect, piston looked fine thru the port. I gassed it up and it started after many pulls but it smoked like crazy. now it was covered in oil and I had sprayed a little into the cylinder as i had been out in the wet for a while so I wanted to protect t a bit until I got around to the fix. But I revved it for like 30 seconds at half throtttle and it never stopped smoking. it sounds pretty ok, but we are talking rolling coal levels of smoke. could smell it for hours inside the house, didn't win me any points with the roomate. I don't know much about 2 strokes but i've worked on car engines my whole life, so normally I'd say oh its burning oil, but with a 2 stroke thats supposed to be a good thing!

tank was totally dry, carb was spotless inside and i did clean it out anyways. filled it with fresh mix, same as I use in all my other tools, anyone got any clue what this could mean? will do a comp test when i get around to it, and clean the plug while i have it out. dang thing seems to take a weird plug so i doubt i have one on the shelf to swap in.

 

[Oldtoolsnewproblems]

oh and the first start was with no air filter on it, box wide open so i could see what was going on and fiddle with the screws/choke easier, as the throttle linkage seems a little sticky and i need to cut a new air filter for it. but long story short, its not a clogged air or fuel filter, fuel is new, air doesnt exist.

 

[Woodslasher]

How's the tune on it? That sounds like it's running pig rich.

 

[grizz55chev]

How's the tune on it? That sounds like it's running pig rich.

And what ratio, 40:1?

 

[Oldtoolsnewproblems]

40:1, i mix everything the same. both screws are 1 turn out which the manual says is the nominal starting point. the smoke is too dense to tune it, i can hardly see the saw! i revs pretty solid tho and is responsive for the 45 seconds that I've run it so far, which seems odd.

 

[davidprivett]

it will most likely clear up with use , you never know what has gone on with it in before you life. just do not 50 to 1 the oil to get it to clear.

 

[heimannm]

Like most McCulloch saws, the 300 Series use an impulse operated automatic chain oiler. If the oil pump is worn, or if the o-ring (Item 17) between the pump and the crankcase is compromised it will allow bar oil into the crankcase and they will smoke prodigiously.



I have a good supply of NOS air filters and a few automatic oil pumps if you would like to purchase parts.

Mark

 

[heimannm]

Spark plugs are DJ6J, DJ7J, or DJ8J (Champion), nothing at all weird about them, perhaps you are not familiar with the tapered seat design.

I have clutches, drums, bars, and mufflers...

Mark

 

[Old2stroke]

Like Mark says, you are probably getting chain oil leaking or being sucked into the crankcase to get that kind of smoke. A good purge is to pour a little straight gas into the plug hole (piston at BDC) where it will leak down into the crankcase, then slosh it around to dissolve all the oil, hold the saw so the plug hole is at the bottom and pull the engine over with the ignition OFF until fuel stops spraying out of the hole. Restart the engine and see if the smoke clears up, if it does you might be able to live with it by just storing the saw with the tank at the lowest point but you might need to rebuild the oil pump.

 

[schreib69]

Like most McCulloch saws, the 300 Series use an impulse operated automatic chain oiler. If the oil pump is worn, or if the o-ring (Item 17) between the pump and the crankcase is compromised it will allow bar oil into the crankcase and they will smoke prodigiously.

View attachment 1013885

I have a good supply of NOS air filters and a few automatic oil pumps if you would like to purchase parts.

Mark

Mark, I have my own question. Similar:
My Stihl just sounds like it is dying: Starts OK, will only IDLE, lots of blue smoke coming from area between SIDE of muffler and the cylinder fins, no acceleration capability at all, just bogs down on triggering. Stihl 362. Any chance I could be so lucky the same thing you describe with the oil pump is happening to the Stihl?! Pleases say yes. Ha! I just had it all apart and "fixed" what appeared to be an chain oil supply problem. It oils fine now. I pulled off the clutch and cleaned the feed tube etc, reinistall it all. . . INcorrectly somehow?

 

[heimannm]

You'll have better chances having your questions answered if you post in the Stihl Chainsaws thread in the Chainsaw Stickies area.

Mark

 

[KASH]

Plugged Muffler?
Kash

 

[chainnut]

got a mucholloch 320 from the trash the other day. it popped when i pulled the cord the second time with a little gas down the carb, but nearly blew out my eardrums. thats when i realized the muffler was fully removed. so i did a partial tear down and cleanup, helicoiled the stripped exhaust studs and a few other mounts, new fuel pickup and vac test was perfect, piston looked fine thru the port. I gassed it up and it started after many pulls but it smoked like crazy. now it was covered in oil and I had sprayed a little into the cylinder as i had been out in the wet for a while so I wanted to protect t a bit until I got around to the fix. But I revved it for like 30 seconds at half throtttle and it never stopped smoking. it sounds pretty ok, but we are talking rolling coal levels of smoke. could smell it for hours inside the house, didn't win me any points with the roomate. I don't know much about 2 strokes but i've worked on car engines my whole life, so normally I'd say oh its burning oil, but with a 2 stroke thats supposed to be a good thing!

tank was totally dry, carb was spotless inside and i did clean it out anyways. filled it with fresh mix, same as I use in all my other tools, anyone got any clue what this could mean? will do a comp test when i get arouprond to it, and clean the plug while i have it out. dang thing seems to take a weird plug so i doubt i have one on the shelf to swap in.

 

[chainnut]

Probably auto oiler pump. Need replacement or rebuilt kit

 

[Oldtoolsnewproblems]

yeah that sounds like theissue. the muffler is soaked in oil even tho I degreased it when i first installed it. I might need to take you up on that parts for the oil pump to sort the girl out. Need to open it back up first tho, make sure its not totally trashed in there.