Hey guys.

I have a thunder tiger .46 and Im having a heck of a time getting it started.

For the heck of it, I hooked up another tank and it started up. Now the only difference between the new tank and the one in the plane is the new tank has smaller diameter hoses. The hoses on the plane now dont make a "pop" sound when you disconnect them.

Can too big if hoses make the engine not start?? Would this be because there is not enough vaccum?

After the plane started, I disconnected the external tank and plugged the internal one back in. It started up, but I think its only because of what was left over in the engine and hoses.

How about some details? What type of plane, setup, etc. Do you have any pics?

Are your fuel lines connected properly (vent/fuel inside tank)?

The size of the fuel line shouldn't affect it starting/running.

Sorry no photos.. Seagull PC-9.. The tank has the 3 prongs.. One on bottom with the weight going to carb.. one on top right going to filler and one on top left (which is bent up) to muffler.

Only other difference between the external tank and the on in the plane was the external tank was higher.. I was just thinking that there was not enough vaccum to get the fuel to the carb. Could it be the fuel tank isnt high enough?

How is the line going to the filler sealed? Is it a fuel dot? Easy fueler? I seriously doubt the tank position would prevent it from starting, but the centerline of the carb should be aligned with the center of the tank or pretty close to prevent problems during flight. If you close the carb down to a high idle and put your finger over the carb while turning the prop (WTHOUT glow starter attached!), it should draw fuel into the carb fine.

Are you using an electric starter or chicken stick? Has the engine been broken in yet?

Check to see if the line inside the tank that goes to the muffler is not pressed up against the inside of the tank. Meaning the fuel line that is bent up, is not being plugged by the inside of the tank, you must have a little space between the line and the tank.

Also, are you sure you don't see any fuel going into the carb. That line that goes from your needle valve to your carb, is there fuel in there or not?

Also, check to see if the line that has the clunk on it is sitting in the fuel. I know this sounds dumb, but sometimes that clunk gets jammed in that tank, the line gets bent and then no fuel pick up.

The last thing is that I have never had a tank with a filler. I always plug that third tube and use the line that goes to the needle valve, to fill. You might try that too, cause there could be something wrong with that filler tube.

See if that helps. Good luck

The filler line is plugged with the silver fuel plugs.. Dont know the exact name of it. If I close the carb and prime it, then take my finger off, fuel will come out of the carb (the motor is mounted inverted).

Chicken stick. The engine has been started before, but not exactly broke it.. Its been ran for about 5 minutes.. I just find it weird it would start with one gas tank and not the other

If you have fuel coming out of the carb when you prime the engine, it should start.

I had a heck of a time getting my TT .46 to start before I broke it in. I had to use an electric starter. I'm not sure why you were able to start it with a different tank.

Try blowing thru the vent (exhaust) fuel line on the offending tank to make certain you are getting a positive flow out the carb side fuel line.

When you connected the second tank, was it sitting on top of the fuselage? Was anything else different besides the size of the line?

Sorry so darned many questions, it's just hard to figure these things out without a visual sometimes!

Yeah, I had it sitting on top of the fuse.. Thats why I was thinking the internal tank may not be high enough.. Im going to get new fuel line tomorrow anyways, just as a shot.. The fuel line I got on it right now is too big.. I mean, big enough to worry me that it would come loose during flight.

why not take it to a local club and see if someone can get it started for you. or failing that if you are going to go to the LHS why not take the plane with you and ask one of them guys. i know a plane is a big thing to take to the LHS but they will probably get it started for you and tell you whats wrong. when i first got my P51 mustang i was at the field trying and trying to get it started. in the end a friend noticed i had not turned the r/x on (i felt so stupid). on another occasion i forgot to connect the fuel line to the carb

I probably will.. Im kind of stubborn.. I like to figure things out on my own until I totally give up.. Im going to take the tank out and change the lines to see if that helps.. If not, then i'll see about getting some help..

im the same i like to try to figure it out myself. and when i cant and i do ask for help it always ends up being so simple that it should have been the first thing i thought of. i dont think it would be that your tank is too low from what you say. have you had the tank out? if you have a 3 line tank as you know you should have your fill line so you can get the gas in/out the line that goes to the clunk and your vent line that goes to the muffler. make sure that the vent is pointing to the top of the tank inside if it is pointing down your tank might not pressurize properly i may be way wrong and if i am i expect to be corrected

bobby,
The large fuel lines could very well be the problem. If they're loose then you may not be getting positive pressure in the tank from the muffler (the tank must be pressurized, you don't want a vacuum).

The large lines could also be causing air to be introduced to the carb line.

Replace the lines and I think you'll be fine. The TT 46 PRO does like a starter at first, it's a tight little engine.
Dennis-

DB it seems like I am just following up on you a lot lately. Do as DB suggests. Try a starter and the new fuel lines. One thing I would add. Try a glow plug with an idle bar if all else fails. I find it helps some in an inverted engine. I have heard of people using an OS type F 4 stroke plug in an inverted 2 stroke. I have never tried it myself. Just repeating what I have seen and read. It may be worth a last ditch try. Good luck.

Mark Shuman

It was the hoses.. Not enough vaccum.. I hard large hoses and should have been using medium sized. Runs like a champ now.

Hi,

I also have a Thunder Tiger .46 Engine. For my case, my problem is a bit more simple than his. Why can't i choke or prime the engine? I set the throttle to idle, and covered up the carburetor with my thumb. After that, I turned the prop a 5~6 times but there is no fuel flowing into the engine? The line fuel line connected to the engine does not indicate any flow of fuel coming into the engine.

Can someone help me out. Thanks a lot!

From Post #2--

Also, how many turns is the High Speed needle valve opened?

G~

2.5

Falcon... set the throttle to wide open ...cover the carb and turn it a couple of times....see if that will prime it.

John

If the engine is inverted it tends to be harder to start for a few reasons - you need to keep your finger over the carb and turn the prop quite a few times to first fill the carb enough to the point that fuel starts to flow down the crankshaft into the head. Then you need to make sure your glow driver is in good shape, as the glow plug will be sitting in a pool of fuel. Of course, too much of a prime and there'll be too much fuel over the plug. So it's tricky to find the ideal prime, but once you work out the right procedure, you'll start it every time.