OS 4D Carb replacement
 

Hi. Are there any carbs other than the OS 4D that will fit the SF .40/.46 engines? I'm cleaning up an SF .46 for a friend and the previous owner split the spray bar wide open by tightening the NV in too far. This led to damage of the low speed screw/tube assembly which slides over top of the spray bar tube (not any more). The previous owner apparently thought the problem was with the barrel - they didn't recognize the damage they has done - and tried to file down the edges of the barrel to force it into the body; causing even more damage. Basically it's trashed and Tower wants $57 for a new 4D carb. That's too much to spend on this repair job.

If anyone has an old 4D they're not using or knows of a cheap alternative carb that will fit - maybe one of the Chinese carbs? - it would be a great help.

Thanks,
David

RE: OS 4D Carb replacement
 

Here is one but it requires a remote needle valve

http://www.hobbypeople.net/gallery/283022.asp

Remote needle valve

http://www2.towerhobbies.com/cgi-bin...?&I=LXJB26&P=Z

RE: OS 4D Carb replacement
 

What is the size if the spigot where the carb fits into the case ?

A Magnum 40-46 carb will probably fit....they are 13mm. ;)

FBD.

RE: OS 4D Carb replacement
 

Thanks, y'all. Tower says the 4D has a 13.5mm throat diameter. A 13mm would probably work with some sealer and the O-ring pressed down really tight. The GMS carb is not remote and is 13mm. At $26.99 it's $30 cheaper than the OS. Do you think that will work?

RE: OS 4D Carb replacement
 

Is the carb held on by two screws ?

RE: OS 4D Carb replacement
 

The SF carb is held on with two screws. The carb throat has two threaded holes in it. The GMS carb is clamped in place like the Tower carbs are. It might still work.

RE: OS 4D Carb replacement
 

Yes it will work, I use 13mm carbs in the K&B 13.5mm cases for years. Wrap the new carb
spigot with teflon tape, then cram it down tight, and tighten the screws to hold it. I know it
sounds kinda Mickey Mouse, but it works good.

The cool thing is....if you crash the plane, the carb pulls out without busting the case. ;)

FBD. :D

RE: OS 4D Carb replacement
 

Thanks, FBD. The owner should be pleased, though, he might still find a "parts" SF on the bay.