I had a plane and engine (OS 40) that sat up one year. I took it out and put some run after oil in and got it freely moving. I then tried to start it and had problems. Looks like I am getting fuel to the carb from the tank, but the engine acts as if it is starving for fuel. When I add a little fuel to the carb intake it starts, runs 10 secs and stops. I have richened the high speed needle twice what it should be and gone back to almost lean. I did notice when I make adjustment on the fuel line the fuel migrates back to the tank. I am at a loss. Air leak maybe? This engine has about 20 flights on it.

Thanks

It sounds as if the engine is starving for fuel. You may want to remove the needle valve and make sure that the spray bar and fuel nipple are clean. Also check closely for any foriegn material. Good Luck, Dave

Also check the pressure nipple on the muffler especially if using Castor as it may also be blocked.

Cheers

Removed the needle valve, and everything is good. How would I clean the muffler valve (nipple)?

Thanks

How would I clean the muffler valve (nipple)? Easy, just poke a common pin thru it.

Nipple was clean/not stopped up. Fuel lines not blocked from muffler either as I blew in it and saw the fuel moving towards the carb. How many turns on the needle value and how many turns on the idle (low end?)

Thanks

LEAVE the low speed alone !!! Remove the high speed needle and pump fuel through the carb till it flows out of the high speed valve, then put the needle back in and turn it in until it just touches bottom, now back it out 2 1/2 turns. It should start there then you can adjust it to what you want. ENJOY !!! RED

Find a way to put fuel (under slight pressure) directly into the carb inlet nipple. You should see fuel spraying from the spray bar in the carb when the throttle is wide open WOT. No spray=blockage. Old fuel can congeal almost anywhere.

Sounds like u got something stuck in the carb. Reset the needles to the original setting, and turn the engine upside down. Open the throttle, and hook up a pump to directly to the carb and pump fuel in.

That should blow the clog out.

Red if have already messed with the low speed. Where should it be set? When I remove the high speed needle, should the fuel flow into the carb or outside the needle arm or both? I removed the entire high speed assembly and blew air thru it. It doesn't seemed stopped up.

Bruce, I removed the high speed needle assembly and put air thru it. It does not seem clogged. I will reassemble and blow into the muffler pressure line and see if I get fuel into the carb. I removed the muffler and cleaned it. The nipple was not stopped up but could my muffler not be pressuring my tank correctly? How would I check that?

if you are useing a stock muffler you almost can't have muffler pressure problems. your problem could be in your tank. your fuel line could have come off the plug inside the tank. an easy way to check that is pump out the fuel and keep the plane level. if all the fuel comes out without a problem then that isn't you problem. you could have a pin hole in your fuel line somewhere. also if you are using the same old glow plug you might try changing your glow plug.

what model os 40 ?

Think I have found my problem. When I pressureized the tank with air and had the needle valve out, fuel starting running into the carb. I noticed that it had a funny color to it. I ran all the fuel out the tank and then pulled the tank. It had all kinds of trash and oil built up inside. I am in the process of cleaning it out, but I think that was the problem.

Can someone please give me the setting for the low end throttle. Someone already gave me the 2 1/2 turns for the high end.

i would start at 5. my Super Tiger 45 ran good at 7 but start at 5 and when you get it running pinch the line and if the RPM increases after a little bit you are rich and screw it in at 1/8 turn intervals till you get it to just drop in RPM then turn out 1/8.

if the rpm drops without increasing, it is lean then screw it out 1/8 turn till it increases then you have it pretty close. usually i really get picky with mine low speed valve because i run tuned pipes. but when you get it pretty close by pinching the fuel line to check it then let it idle for about 15-20 seconds then increase throttle. if it chokes and dies lean it just a little bit. do this until you get a smooth transition from idle to full power. doing this will simulate a landing approach. if you have it too rich and are too fast or too slow and you give it power then your engine dies and you are SOL. if you are too fast you can still easily put it on the ground but be careful cause you will hit the ground harder than nomal. if you are too slow then just try to land it like you normally would no matter where you are because that is about all you can do. remember the slow you land the less likely you are to mess your plane up. better to be a little to fast than too slow.

we need to know what model the engine is to give you the correct setings,

.40 OS Max FP

bump

there is no low speed neddle setting on the stock carb for an os fp 40,it uses an airbleed type carb aqnd you will have to play with srew a little at a time to set the idle mixture,it has no significant affect on the high end.

Air bleed carbs are different than the twin needle carbs, turn the low speed airscrew screw in to ritchen it, out to lean it.

Start with 1/2 the airbleed screw showing thru the hole in the carb is what my .40LA book says.