After rereading all the responses and checking and replacing fuel lines, the fuel tank, glow plug, carburetor, I thought the engine was not getting the proper amount of fuel. I bought a Conley fuel pump thinking the fuel feed problem would be corrected. It wasnt. This engine just refuses to run consistently. I give up. It was all I could do to not smash it with a hammer. I may still do that. This is disappointing because when it did run it ran well. The Tower trainer I have it in would almost do vertical flight. I also am glad to see that I am not the only one having problems with this motor. I kept trying every thing I could think of off and on for the past year and a half. I kept thinking eventually I will find what I missed. I dont want to flame anybody but I will not buy any MDS product ever. Did I mention that I had two of these motors and neither one ran right. I have smashed two planes into oblivion and beat up a third. NO MORE. Thanks for all the help everybody.
Mike

I've been doing ALOT of fiddling and I've gotten my Dad's MDS 48 to run OK, but it too won't run consistantly. I've gotten it to run well for 1 flight, but I have to retune it before the next one. The 46 FX on the same plane starts with a chicken stick within 3 flips, and never needs any tuning unless the weather has changed ALOT since the last time.

I have 2 MDS 148 's. I have had sucess with Byron's 5% fuel. I also have an oscellating pump connected to them. The units tend
to overheat when cowled. Try larger exit air exits and maybe air deflectors to direct the air towards the head.
Another member of my club has had the same problems that you report. Try running without the cowl to confirm its a heat
problem. Again my engines are very fuel brand and nitro content, fussy. 15% caused it to overheat. I noticed that my engines
are much hotter than other brands of engines ( boils spit ) This is why I think they have a heat issue. Also there is not as much fin
area as other brands of engines. Now in the process of constructing some internal cowl fins to direct the air flow. I hope this information is of help.

Wayne Marcy
[email protected]

Hey Mike, did you ever get your MDS 48 to run properly? I sent you an e-mail afew days ago telling you how to correct your problem, but maybe you didn't receive the info; anyway if you like you cantact me at [email protected] hope I can help, CHET

Sorry Chet I must have deleted your message by mistake. I get a large amount of spam and sometimes I get a little over zealous with the delete key.

Well sir; I have two MDS 40's a 48 and a 68 and I find them to be very high quality and dependable after they are properly adjusted. I know that your fuel system is probably in first class shape, but please verify that the fuel supply tube in the fuel tank is at least one half inch below the centerline of the carburetor spray bar. Assuming that your engine is equipped with an MDS carburetor; good glow plug, fresh fuel---------- start the engine and allow to warm up for two or three minutes at an idle. If it won't idle, turn the idle mixture screw counter clockwise one half turn. Restart and let the engine warm upat an idle, then FIRST (the idle mixture actually controles the fine tuning of the high speed mixture, believe it .) With the engine at idle, very carefully and deliberatly pinch the fuel delivery line as close to the carburetor as is safe and wait for the engine to quit running. The RPM should increase a substantial amount, similar to what you want when pointing the aircraft up at full throttle to check for proper high speed running. Once the idle mixture is set, adjust the high speed mixture the same way. MORE Fuel(rich) turn counter clockwise. Less Fuel(lean) turn clockwise. You may have to do this two or three times to fine tune the carburetor. Please remember that it is of the utmost importance to adjust the idle mixture properly FIRST, then the high speed mixture. Be careful,good luck, and keep in touch, Chet

We solved this once with a new guy at the field and it turned out to be really simple, Mike. His MDS would stall on take-off every time. With it running at full speed on the bench I noticed the muffler pressure line beginning to clutter up with oil. We yanked the line and the engine instantly picked up speed and began to run a lot better under all circumstances. Another point of interest is that while running at full speed w/o the pressure line connected, gobs of oil squirted out of the muffler pressure fitting. I haven't checked to see if this happens with other engines that do not suffer from "mystery stall" and I can only assume that oil stopping up the vent line is what causes the running problems, but everything works fine now that the tank is vented to the atmosphere.

I have 5 MDS engines , a 1.48,2-68's,2-48's and have had a great time with them all. The 1.48
was the hardest to get set correctly at first, but once you get it the power is great. My brother was getting
into R/C and purchased a Sig LT 40, I of course told him to put a MDS 48 in the nose. After running the motor
a little we took to the skies, great power - but it would occasionally die in flight. I set the motor the same as
I did all my others to no avail. Finally I realized the only difference was the fuel we were using. He had purchased
a good brand but only at 10% nitro. I mixed it a little and brought it up to about 17%. That's all it took, as long as he has good nitro content it run's superb,no more dead sticks. I hear people bad mouth 1 brand or another
and have seen how they are so happy to adjust, adjust,adjust. Motors are basically the same and once they
have been set I only occasionally have to change it a click, due to temp,humidity,changes. Use a chicken stick
to start them. Fly and have a blast!!!!! I put 1 of the 68's on a Kadet Senior and love to watch peoples mouths
drop as I pull vertical with the big bird. Great power from all of them. I wish you great flying

One word for you all



SAITO