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Help with OS 46 FX needed

I have a low time OS 46 FX (about 1/2 gallon through it) I have had since new. After the using for the last time last year, it was run dry of fuel, after run oil put in and stored in a dry location. The engine HAD BEEN running last year with the main needle open 2 1/2 -

2 3/4 turns. Low end has not been touched since it was set. The engine is now in a new plane mounted sideways.

Problem: It will not run beyond the prime.

I have done/checked the following and am at a loss on where to go from here.

New OS #8 plug (verified the plug is good - All coils, except the top

1/2 are lit and bright) Fuel is getting to the carb Fuel is fresh (Jug was opened yesterday and put on the field box) Fuel tank/carb height is correct Compression is excellent Made sure the main needle valve has no junk/crud in it. (Removed and cleaned the needle valve, blew out the housing and visually verified the housing is clear and there are no burrs or anything on the needle valve.) Replaced ALL the fuel lines, including the tank lines and made sure they were tight Made sure the clunk was clear and free moving (tank is new) Pressure tested the tank, everything is tight - no leaks There are no kinks in the lines Used the power panel with the voltage set a 3 volts for the glo plug. Tried various main needle valve settings up to and including 4 1/2 turns

- no difference

The engine primes easily. It runs out the prime, then quits. Any ideas on where to go from here ? It SHOULD run, but it isn't. The engine ran great before I put it away last year.

Reply to
Ted Campanelli
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May sound dumb but do you have the correct fuel lines going to the carb and muffler? Been there, done that...

Reply to
Fubar

That's why I started colors for all my planes Blue for fuel, pink for pressure... Good luck, something is keeping it from getting a supply of fuel. Make sure you don't have the lines reversed. Andy

We can make a box of wood.....FLY!!

Reply to
RCPILOT48

Had similar to this once. Turned out to be the cavity that surrounds the needle valve was gunked up. Where the fuel line connects to the nipple then fuel goes into cavity that surroundes the needle, this cavity was partly blocked. You can take the needle out and all looks clear, used a piece of nylon fishing line with hook bent on end to clear. My twopence worth.

V /////////////

engine

plug.

Reply to
The Shaw's

Are you starting the engine at a low throttle setting or at 1/2 or greater throttle? The main needle only controls fuel flow at 1/2 throttle or higher. You may need to clean out the low speed needle area.

Reply to
Paul McIntosh

On 5/12/2004 8:58 PM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

Yep. I use different color lines so I can MINIMIZE that problem. :)

Reply to
Ted Campanelli

Hey Ted, here is my two-cents worth;) I have 4 OS.46's running right now, and the needle valve setting vary from 3/4 to 1 1/4 turn open. I believe this varies due to the brass hole the needle screws into.

Good luck

Reply to
Reply thru newsgroup please

Ted,

If you haven't found the problem by now, try checking the muffler pressure fitting. Sometimes crud gets in the hole and plugs it.

An easy check is to put a finger over the muffler outlet and flip the prop, watching for fuel traveling in the "in" carb line. Might have to flip several times to establish pressure in the tank. No glow driver attached, of course.

Happy Flying, Mike

Reply to
Mike

Mmmm, there is something wrong here because all the motors I know of (incl my OS46 FX) run with about 3/4 to 1 or max 1.5 turns of the needle valve open when using muffler pressure. Only if you take the muffler pressure off do you need to open the needle that far. I would check that the pressure vent in the muffler is not plugged and that there is not a kink in the pressure line. I would also check that the pressure feed piece of brass tubing is not jammed up against the top of the tank. I generally file a V groove in the top of that piece of brass so that it cannot become blocked. Failing all this and the other help you get, pull the motor and check it on the bench. There is nothing more frustrating than trying to fix a motor problem in the 'plane when you do not even know if it runs ok on the bench. Gord Schindler MAAC6694

Reply to
Gord Schindler

Ted, I replaced the carb on an engine about a week ago and had the same symptoms you are describing until I finally got the LOW end needle valve open far enough. My engine is side mounted too... Don't know if the side mounting is relevant but I'd open it a turn or two (yes, I know they are supposed to be minor adjustments but you can always close it back up once the engine is running at the low end at all) and try again. Of course it could be that the low end valve is gunked up so cleaning it out might help. Good luck and let us know what happens.

Jack

Reply to
Jack Sallade

Regards your OS.46FX fuel problem:

Have you checked the "vent" tube in the fuel tank? Make sure it is clear of the top and venting properly. No air in, no fuel out! Also, vent line connected to your exhaust? You need some exhaust pressure to help push the fuel out of the tank and to the engine. Good luck.

Jonde

Reply to
Jonde

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