Chainsaw carb tune

Carlman

New Member
Dec 3, 2008
22
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0
Perth, WA, Australia
Hi all hope this is in the right spot,

My chainsaw bike when warm was bogging and dieing when i reved any higher than idle, have tried to tune via adjustmnt screws, caould someone please link me to either a thread on here or an external site that will show me.

much appriciated

carl.
 

rgvkid

New Member
Sep 21, 2008
110
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Los Angeles,CA
Try Google "Chainsaw Tuning" There are a few easy to read procedures. I have a 33 Poulan and i have come to terms that is Sucks. Well, to the point that it doesn't fit my needs and i think i already screwed it up from trying to tune it right. If its to lean, which has the most power, it will over heat and seize. Once it cools down it will run but you have to play with the tuning so that its rich enough to stay cool but still keep some power. Im going to pick up a 40cc Poulan Tomorrow for $60 that might have a bit more power to fit my needs, but i really just want to save up for a more reliable Honda GX50.

Heres a basic link:

Request Poulan chainsaw Carb Tune-Up Procedure - GardenBanter.co.uk
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
I don't know what kind of cylinder or liner your Poulan has, but if you seized it once or twice, you may be all done...
 

Carlman

New Member
Dec 3, 2008
22
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0
Perth, WA, Australia
ive done everything as per those manuals but alas i can get it to idle but when i give it the juice above slightly past idle she dies on me no matta what i have the h screw at. could there be another prblem?
 

comfortableshoes

New Member
Jul 22, 2008
606
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Beverly, MA USA
have you checked for an air leak around your carb?

If it's dying when you give it gas it's probably running either too rich or too lean...

dial the H screw in all the way. Start her and see what you get. Does it run? At all?.kick2

Back it out to 1.5 turns out use that as your base line. (^)

See what happens when you give it gas. Listen to it.

When mine was lean it would sound like it was knocking, esp when I was revving it WOT... when it would get too rich it would bog down.

Turn the screw out (counterclockwise) a quarter turn at a time- while the engine is running. You'll find the sweet spot eventualy. Don't be afraid to screw it in gently all the way if you can't remember where you were at. I found it helped to ride the bike between every quarter turn, because the engine acts differently when under load.(^)

The ryobi wanted me to back it out 1.5 turns and about another 1 quarters so a total of 2 full turns is about where she is at now.

The right mix run slightly rich is best. we are using these engines in ways never intended when designed- and they get abused...

Next thing is what are you running for mix? I ran my first 2 tanks through rich- 20:1 manufacture recommends 32:1. when I switched to the right mix it made a world of difference.

Another thing to check is the filter on the muffler. Sometimes they get clogged up that can cause bogging and dying... sometimes it's the muffler that is just plugged as well. Take the muffler off and see if it runs.

Next airfilter? Does it run with it off? IF so theress the problem
 

Carlman

New Member
Dec 3, 2008
22
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Perth, WA, Australia
I am running no muffler of sorts just a bit of shet steel cut to the same shape as gasket with a 6mm hole drilled as exhaust port. No airfilter at the moment but will have one on when i et her running.

Its deff a bogging not a knock. how would one check for an air leak, could his cause it?
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
I am running no muffler of sorts just a bit of shet steel cut to the same shape as gasket with a 6mm hole drilled as exhaust port. No airfilter at the moment but will have one on when i et her running.

Its deff a bogging not a knock. how would one check for an air leak, could his cause it?

That's part of it...you should have some kind of opening for the exhaust and I don't think 6mm is enough. Plus the volume of the chamber part of an exhaust muffler helps out too. Runnin no air filter will suck up a lot of grit and eat your liner/ring(s) too.


Having said all that, there is a WOT tuning trick I have seen used by the locals. The set the saw so held WOT with NO LOAD it is rich enough to break into a four cycle, when the load is applied (putting the saw to a log) the engine should clear out and break back into a rich two cycle. Start with the H screw rich and lean it out until you get there.

If your engine isn't already whooped.
 

Carlman

New Member
Dec 3, 2008
22
0
0
Perth, WA, Australia
it cant be part of it as before i was having the same prob wih no exhaust, and a homemade 1 it idles fine so cant be air filter letting grit in.

no matter what i do to adjust it it still bogs out, this is a engine with 1 hr cutting time on it aswell. great compression.

how would i clean the jets, ie where are they, my mower shop said prob a blockage.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
it cant be part of it as before i was having the same prob wih no exhaust,
QUOTE]

Hmmm.... Try putting the exhaust back on? No back pressure will make a two stroke not transition from idle to partial or wide open throttle. So will too much back pressure.

Also, if you have too much of a load on it, it will never rev up no matter how much you tweak the carb.

You could have a blockage in the high speed jet, but it would tend to start throttling up, and then cut out, not bog as you've described.