Alky carb conversion?

[Fruecrue]

Look at FHS Oil in the RC link....

https://www.bmikarts.com/RC-Racing-Fuel_c_512.html

Hope the link works. Forgive my ignorance, is there a detailed description to the fuel content anywhere? Descriptions seem very basic.

Edit: link may be another product, I’m having trouble accessing the FHS website.

 

[Billy Currie]

http://fhsoils.com/product/competition-chainsaw-fuel/

Try this one...

I have used their oil in kart racing and use their 62r as a premix with gas sometimes. I have not used their fuel for a saw yet. I have ordered a little bit of nitromethane from them.

 

[Fruecrue]

http://fhsoils.com/product/competition-chainsaw-fuel/

Try this one...

I have used their oil in kart racing and use their 62r as a premix with gas sometimes. I have not used their fuel for a saw yet. I have ordered a little bit of nitromethane from them.

Excellent, thank you.

 

[Chainsaw Jim]

They sell methanol racing fuel at a place by me called Northwest Solvents and Supply. It's an establishment you wouldn't expect to find that sort of thing and it doesn't show up in results for any fuel related searches.

 

[Sty57]

What is u4.4? turbo blue or purple?

Light green

 

[Time's Standing Stihl]

I am working on a carb off and on. It's a Chinese Tillotson HS-320A. I don't know if I will be successful or not, but so far I have slightly enlarged the fuel pump cavity, and I am working on the needle/seat area now. I have noticed opening the seat up that it is next to impossible to get the needle to seat when pressure tested. That is my battle at this point.

I didn't like the venturi that the carb had, so I removed the choke shaft and throttle shaft. I increased the bore diameter of the choke side until I opened a blind screw hole and increased the bore diameter of the throttle side to match the choke butterfly installed on the throttle shaft. I'm not sure if it will work, but my goal was to make a more pronounced venturi inducing a lower pressure hopefully pulling harder on the main jet.

If it doesn't work the trash can is never far away.

How much reduction did you end up with?

 

[Stihlbro]

http://fhsoils.com/product/competition-chainsaw-fuel/

Try this one...

I have used their oil in kart racing and use their 62r as a premix with gas sometimes. I have not used their fuel for a saw yet. I have ordered a little bit of nitromethane from them.

FHS are good people.

 

[Fruecrue]

FHS are good people.

Good to hear.
I placed an order last night.

 

[Billy Currie]

How much reduction did you end up with?

I have not tried it. I am still working on the needle and seat. The needle and seat issue could be the end of this carburetor.

I do have the capability of measuring the pressure drop, but I have not gotten that far yet.

 

[Stihlbro]

The 320a has a small needle, right?

 

[ManiacalMark]

Light green

I assume its AV fuel

 

[Sty57]

I assume its AV fuel

No
It's made by VP

 

[ManiacalMark]

Interesting what's the octane on it?

 

[Sty57]

103 I believe

 

[Billy Currie]

The 320a has a small needle, right?

It's about .160" in diameter and kind of long. I don't have a measurement for the length.

 

[ManiacalMark]

103 I believe

Ah, I believe turbo blue is 116

 

[Wisconsin Welder]

I have no idea what I'm asking here, but, here goes........

If you are going to use carb X on a saw with alcohol and need to modify all the fuel circuits to flow more fuel,
Could you instead use a carb from a much larger saw that would (I'm guessing) have larger fuel circuits and make an insert for the throat of the carb to reduce the airflow down to where you need it?

Would having the larger jets and seats make it easier to adjust?

 

[huskihl]

I have no idea what I'm asking here, but, here goes........

If you are going to use carb X on a saw with alcohol and need to modify all the fuel circuits to flow more fuel,
Could you instead use a carb from a much larger saw that would (I'm guessing) have larger fuel circuits and make an insert for the throat of the carb to reduce the airflow down to where you need it?

Would having the larger jets and seats make it easier to adjust?

A carb for a larger saw also has a larger throat and venturi for air, so it too would need to be drilled to get the right fuel to air ratio

 

[Wisconsin Welder]

A carb for a larger saw also has a larger throat and venturi for air, so it too would need to be drilled to get the right fuel to air ratio

Thats what I'm sayin, make an insert for the larger throat, then you could machine a venturi you liked, and size the air portion of the carb for the application. Basically sleeve the throat of the carb.

Still a lot of screwing around, but maybe easier than the fuel circuits

 

[Deets066]

Thats what I'm sayin, make an insert for the larger throat, then you could machine a venturi you liked, and size the air portion of the carb for the application. Basically sleeve the throat of the carb.

Still a lot of screwing around, but maybe easier than the fuel circuits

JB weld can narrow up the Venturi, but still.. a big carb on a small saw needs big jets anyway.

Big carb, alcohol on a small saw needs huge jets