Thread Tools
Jan 17, 2012, 05:24 PM
Registered User
Thread OP

MDS .40 carburator problems

Hello! I have an old MDS .40 glow engine, and, the reliability of the carburator is very poor. It is impossible to make a smooth transition between idle and high speed. Somebody know the solution? The best way is to change the carburator? Is a replacement of this carburator available? Is it possible to fit some OS carburator to the engine? Any help is appreciated! Thanks!
Sign up now
to remove ads between posts
Jan 17, 2012, 09:38 PM
Registered User
earlwb's Avatar
You might peruse this thread here, that I have linked to, to see if what I did on some Russian engines is the problem you are having or not. I needed to make a new low speed needle to fix a over rich low speed condition that affected the mid range too.
Farther down into the thread I go into more detail about my solution to the problem.
Jan 17, 2012, 10:47 PM
Registered User

Carb fix

Make sure the O rings are in place. You must relocate the muffler pressure tap to the center of the D on MDS on muffler flange. Remove the main needle assembly and with a spotting drill chamfer the seat the needle screws into. This will fix your problems.
Jan 20, 2012, 04:33 PM
Registered User
Thread OP
Thanks a lot for your help! anybody knows where I can buy a new C2 carburetor for this MDS engine if I make something wrong with the repair of the problem?
Jan 20, 2012, 09:50 PM
Registered User
earlwb's Avatar
Usually everyone goes for a Perry Carb instead. They work really well.
Just choose a carb with the outer housing size to match the hole in the crankcase intake and also pick a inside bore size to match as needed.
Now if you have a lot of engines, you could use a carb you saved after wiping out a engine or wearing it out.
You could try the MDS engines company in Russia, they might have some parts. At this time I am not sure they are really around anymore, but maybe they are.
Jan 20, 2012, 11:20 PM
Registered User
I TOBOR's Avatar
The probablem is not that the carb is unreliable, the short taper on the LS needle means that it has a very narrow sweet spot. The Perrys also have very narrow midrange sweet spot.

Quick Reply

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion K&B 0.40 square carburator issue Mauricio2346 Engines 4 Jun 19, 2011 11:30 PM
Sold Fox .40 carburator flynfrfun Aircraft - Fuel - Engines and Accessories (FS/W) 2 May 15, 2011 09:30 PM
Discussion MDS .40 Problems Mr.Me Engines 14 Jun 23, 2007 06:56 PM
Discussion problems with MDS 40! spitfire123 Engines 7 Jun 30, 2006 03:34 PM