Carburetor mods and mod theories

[paragonbuilder]

That was weird double post 20 min apart???


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[jmssaws]

I never have.

 

[huskihl]

Seems to me that more air would flow through one carb than 2 in series. The longer the tube that the air flows through, the more restriction there will be. But deeter's point is valid, using a carb as a spacer to allow for better atomization.

But a dual carb/filter setup in parallel, that's a different trick pony. Now you're allowing double the airflow. But you'd also have to match up the adapter manifold and increase the size of the intake on the cylinder. And increase the size of the exhaust outlet to get rid of it

 

[Chainsaw Jim]

Not sure if this is the right thread or not, but I,ll post my thoughts anyway.
I picked up a poulan throw away saw the other day it play with. I was thinking of pressuring the carb with a leaf blower... I think of either building brackets to mount it above the saw or feeding it with something like a sum pump hose And leave the leaf blower on the ground... I know that this is totally not practical! But seems like it would be fun.

That would definitely be in the spirit of mod theory in my opinion. I've had similar thoughts of mounting micro oxygen bottles to the saw to supplement at wot. Basically bottle feeding pure oxy.

 

[Deets066]

I've thought about boost bottle too.... It would catch the spit back (if you let off the throttle)

 

[Chainsaw Jim]

Well only the wood will tell. I got this thing together and fired it up and holy freakin smokes! if it eats wood the way it sounds like it wants to then this will be something fun.
I don't have my hopes up too high though...idling good and revving up is only the first half of the requirements.
One other mod I did was making the intake boot larger at the carb end. It was using the smaller size on the left and I enlarged the housing to fit the larger ring. The crusty one in the pic was for reference. There's no way I was putting that in there.
I do have plans on fastening the filter braket to prevent the housing from rattling apart.

 

[CR888]

I don't want to sound negative or be the party pooper but the same amount of air will come through drawing double the amount of fuel. You would need to re-jet the carbs to restict the amount of fuel so its not piggy pig rich. I think your going round in a circle on this one for no good reason. I would make the most of the fuel circuits on one carb having it perform the best it can for the saw. Looks pretty funky though

 

[Deets066]

What do you have the screws set at on each carb?

 

[Chainsaw Jim]

I don't want to sound negative or be the party pooper but the same amount of air will come through drawing double the amount of fuel. You would need to re-jet the carbs to restict the amount of fuel so its not piggy pig rich. I think your going round in a circle on this one for no good reason. I would make the most of the fuel circuits on one carb having it perform the best it can for the saw. Looks pretty funky though

The outside carb is larger than the inside carb so it can achieve more air velocity with the added fuel. The inside carb was the carb that was already on it and was still at the same tune when I fired it up. And yes it did run way piggy pig rich. The low side on the inside carb needed leaned a little to idle right then I revved it and it tried to rev but just gargled like it was flood limited. I thought oh well, it didn't work. So then I decided to see if it would change anything turning the high side in on the inside carb and it responded very well and went way up there. So like I said...only the wood will tell.

What do you have the screws set at on each carb?

I lowered the metering lever in the outer carb to help avoid pulling any fuel at idle.
I decided to set the outside carb low to just barely cracked, about 1/8 turn or so, and the high about a quarter turn. I'll have to check to see exactly what it is when I wake up. I'm hitting the sack.

 

[Deets066]

This could be an easy way to run alcohol on a race saw without mounting a huge carb

 

[mdavlee]

Guy on Facebook has this one built.

 

[idiotwithasaw]

Is it OK that I have a little bit of a bone looking at that pic?

 

[Redfin]

Guy on Facebook has this one built.

Id like to see the intake after the carbs.

 

[mdavlee]

Id like to see the intake after the carbs.

Welded block. There's more pictures on chainsaw hoarders group ok n facebook

 

[jacob j.]

Welded block. There's more pictures on chainsaw hoarders group ok n facebook

Is that Adam Clarke's build? Adam has built some awesome stuff.

 

[mdavlee]

Is that Adam Clarke's build? Adam has built some awesome stuff.

Yeah he welded the intakes on. That guy is on the east coast who owns the saw.

 

[Redfin]

Wonder why he didnt leave more meat between the two vstacks?

 

[Chainsaw Jim]

I still need to get it dialed in.

 

[idiotwithasaw]

I still need to get it dialed in.

I think with the direction you are going you really need a pipe on it for it to flow properly. Still a cool idea.

 

[Chainsaw Jim]

It has a pretty mean air leak where the boot meets the carb which can be heard at the end when I hold the throttle. It did that originally and I used a rubber spacer to seal it. That spacer is sitting right here on my table in front of me and not on the saw.