I have a "new" Super Tigre 45 that I have had about 25 years. Since I haven't flown much the last few years I put it on a trainer to sharpen my skills. Now I remember why I switched to O.S. a long time ago. The S.T. started instantly and ran until I just touched the needle valve. It died and now won't hold suctionfrom the tank. I removed the carb to make sure nothing was plugged. It will draw fuel but only for a moment. This reminds me of the Super Tigre inflight flame-outs of old. I have a new O.S. 46 waiting in the wings if this S.T. won't run.

My second engine was a super tiger. I was a little skeptical at first being that my first was an OS. It was rough to get started , then had to really break it in on the ground for about 1/2 gallon...but once I was done - that thing was POWERFUL!!!!

Have changed the fuel lines, checked the o-ring. You can put a piece of fuel tubing over the needle valve to seal it. What is the tank height? Put your finger over the exhaust exit and see if it will go to the carb. Is the o ring under the carb good. Sounds like an air leak some where.

You will find threads about ST engine in the engine forum. I have had very little trouble from my ST engines. I have one GS-45 that has out lasted (2) OS 46's.

Dru.

Edited for spelling.

I have a Super Tigre G-61 ringed on my King Kobra that is as reliable as any O.S. Max engine I've owned. I also have an old Super Tigre Bull Ring .46 that is dead solid reliable.

You can have problems with most any brand of engine until you become familiar with how a particular engine responds to various glow plugs, fuel types, propellers, weather conditions, tank setups, and tuning specifics. Too many pilots learn to tune on O.S. Max engines and then decide that any brand that doesn't behave exactly like their O.S. Max engine did to all of these variables must be defective.

I don't have any doubt that Super Tigre has produced it's share of turd engines over the past few decades, but you can't keep bashing a brand because your 25-year old ST .45 needs some carburetor help.

A friend of mine had trouble with his Italian ST G40 not throttling, poor idle, hard starting etc. Turned out it was a leaking head gasket. Had to re machine the head to get a good seal but it transformed it into a fantastic runner. It is not the first time I have seen trouble with them with leaking head gaskets.

If an engine is mounted so that the needle valve is higher than the level of fuel in the tank, no model engine will "hold" suction in the tank. Fuel will always run back to the tank when the engine's not running. If the needle valve is mounted lower than the level of fuel in the tank, fuel will always tend to siphon into the carb and drip out if the engine's side- or inverted-mounted.

The ideal tank height is with the centerline of the tank level with the needle valve or no more than about 3/8" lower. This applies to just about every engine .90-size and smaller. Larger engines may need to have the tank closer to the needle valve centerline because they usually have lower fuel draw.

Whenever the fuel level is higher than the needle, and the fuel lines are full of fuel, then fuel will siphon into the carb. You can prevent this by having the fuel tubing make a small loop above the level of the top of the tank. This, then, will prevent siphoning if you make sure the fuel lines are empty after running. You can do that by putting your finger over the air intake and gently turning the propeller backwards. This will put a bit of positive pressure in the line and push the fuel back to the tank.

Thanks for the information. Yesterday I removed the engine from the airplane and mounted it on a test stand. It had the same problem as it didon the airplane. ( would not hold suction )
I removed the fuel line from the carb and blew back into the tank with the vent line still connected to the pressure tap on the muffler. The tank pressured up and there was no flow out the vent. The pressure tap on the muffler was plugged solid. I took a small drill bit and cleaned it out..... problem solved. Since this was a 25 year old "new" engine, I was surprised. I believe an insect had built something into this hole. I recenly had the same problem with a nail gun. A small waspbuilt a mud nest in the opening of the air intake. They also get into my tool boxes and build mud nests into tools etc.. The pressure tap on the Super Tigre may have been a spider's home. Anyway, thanks again to everyone who responded with ideas.

A.D.