Nitro carb for Weedeater conversion
 

Hey guys, it's been awhile since I habve been on this forum. So long I forgot my old login. Anyway, I have a stripped down lightened up 21 CC Weedeater motor that I want to run on glow or gas/glow and was wondering what nitro carb might work. I thought maybe the Super Tigre .90 carb but wasn't sure. Motor ran good on gas and spun a 15X6 to about 7400 but proved to be too heavy for the SPAD it was in. Now that she has dropped more than a pound I wanted to lose the heavy walbro carb and go strictyly with a simple two needle nitro carb. Adaptor would be in the works as soon as I decide on a carb. Thanks guys for any insight.

RE: Nitro carb for Weedeater conversion
 

The Super Tiger .90 carb is about 9mm venturi. Should work ok for you. Remember though that since it doesn't have a fuel pump like the Walbro, that your tank position will be more critical. Install it like you would for a glow engine; close to the engine, with the centerline of the tank at the same height as the carb, etc. and you should be ok. Muffler pressure to the tank would worry me a bit in a gasoline setup. If you are going to use glow fuel, use muffler pressure. If you are going to use gasoline, look into using crankcase pressure to pressurize the tank and help fuel flow/delivery. You will need a one way valve for the crankcase pressure to work well.

The carb isn't designed for gas and will probably be finicky on gas/oil only. Should be ok for pure glow or Gas/Glow with the above things in mind.

AV8TOR

RE: Nitro carb for Weedeater conversion
 

The engine is slightly larger than a 1.2 so a 120 carb would be the guess

But a 90 carb would work well especially if it is a Weed Eater 21

RE: Nitro carb for Weedeater conversion
 

Thanks guys. You wouldn't happen to know the out throat diameter would you? I need to machine an adapter.

RE: Nitro carb for Weedeater conversion
 

Outside diameter of what? The Super Tiger .90 carb? If so let me know and I'll get it to you tomorrow as I have one out in the shop.

AV8TOR

RE: Nitro carb for Weedeater conversion
 

Outside diameter of carb throat: .589"

RE: Nitro carb for Weedeater conversion
 

Yeah, sorry I meant the OD of the Carb. Thanks w8ye. av8tor1977, how much do the carbs usually run at a good price? A link? I have seen them for $35 on line. I'm currently in Iraq for a year and didn't quite get to finish the conversion, so that will be the first project when I get home. Thanks again guys.

Chris

RE: Nitro carb for Weedeater conversion
 

Hi,

I don't know what they run... I just happen to have one from an engine I converted to Gas/Glow with a Walbro. I would probably check Tower Hobbies for one.

Good luck, and keep your head down!

AV8TOR

RE: Nitro carb for Weedeater conversion
 

Check the bay under perry carb, for the best price.
Or Google perry carb. On their site they have conversion tables that list ID and OD
and shows what fits what.

RE: Nitro carb for Weedeater conversion
 

Had another question. What is the measurement of the mounting bolts for the walbro carb. I was home on leave and didn't get a chance to mic the holes on the carb to make my adapter. Could anyone get a measurement for me so I can start on my adapter? Also, if I tapped the hole where the carb mounts in the head and used that as tank pressure, would this work OK? The same hole the walbro used for pump function. I will be running strictly glow fuel. Thanks guys.

Chris