I have a Thunder Tiger Pro 46 that runs like a top at idle and full throttle and the transition is smooth. The problem is it is really difficult to start. Bring it in and gas up and same thing, it is still tough to get started. The "experts" in the club have played with it but can't get it to start like most of the others do...with a flip or two of the chicken stick. It takes 30 seconds or more with the electric starter to get it going. And often it floods and we have to pull the glow plug to clear it and try again. Once started, it purrs like a cat.

I have a couple of TT Pro 46's, probably the best engines I have. Not a lot of information but I'll make suggestions based on what you have given. How's the condition of the glow plug? Any doubt, put a OS #8 in it. Are there any loose engine bolts (head or backplate)? And my biggest suspicion is the tank and plumbing. With your finger over the venturi, you should be able to flip the prop about 4 times and see the fuel being drawn to the carburetor. Once I have the fuel up to carburetor I'll take my finger off the venturi and continue to flip another 4 times briskly. All of this prep without the glow plug lighter on. Then all it should take is a couple of bumps with the electric starter, and it should start right up. Set the throttle a little above idle when starting. That engine in my opinion is as good as any OS. I suspect the tank and plumbing is the problem more than the engine.

I have one of these engines and I agree with Tom, it is the best engine I have ran. This engine has been burried several times from bad crashes and it still runs incredibly. One plane I had it in called for an inverted installation. This made it harder to get the engine primed, but once primed it has always started with no problem. I have never used a starter on it, in fact I don't even flip it over to start. I just give the nose cone a quick spin backwards and it will pop over and run forward. It is a great engine and a powerhouse for its size and price.

1.) Make sure your glow plug igniter is getting hot enough and 2.) make certain the tank isn't too high or low.

flooding? Sound like its too rich on the low end.

or you fuel tank is too high relative to the carb.

Also after every flight its worthwhile tipping the tlane on it side and drainingany excess fuel out via the exhaust. You'll be amazed at how much oil has accumulated in there if its too rich.

Sir stock settings on the Pro46 are 3.5 on the high and 4.75 on the low. This should get the engine started but it's up to you to tune it when it's at idle. If you are still having issues please send in the engine to Ace Hobby and we wil be more than glad to service it under warranty if it is within the 3 year warranty period.</p>

ACEHOBBYS

Sure never expected a reply from you. One thing for sure, I will be looking at ACE for future supplies with this type of customer service.

Idon't believe it is the engine nor do the experienced flyers. It runs like a top on the low and high ends once started and no problem in flight. So it would have to be fire or fuel. We replaced the glow plug but that didn't help and the plug glows ok when removed from the engine and hooked to the glow starter. But I am going to try the OS #8 plug as recommended in a post.

So it seems the problem would have to deal with fuel.

Now the centerline of the gas tank is nowhere nearly in line with the needle valve as I have read it should be. The needle is just a hair above the top of the gas tank and with the LT-40 there is no way to move it. But I don't think that is the problem either as there are other LT-40's and Senior Kadets running TT engines and they don't have a starting problem.

I don't know what it is but I am going to replace the whole fuel system (and pressure test it first which I did not do with this one).and see if that solves it. If not I will take you up on your offer because the engine is only a couple of months old.

If after priming the engine, you are cranking it a lot ( as you indicated ), and it otherwise runs good, once started, the problem is NOT in the engine nor it's tuning.

Don't change the plug. The engine is already running fine!

Use clear fuel tubing from the tank and watch what happens to the fuel after you prime the engine.

I suspect the fuel is running back into the tank.

Also do you bring the throttle to idle immediately after priming? This helps prevent the fuel from siphoning back into the tank.

If you momentarily place your finger over the exhaust outlet while cranking will it start easier?

opjose

How do Ireference and include the quote I am replying to.

No, I have fuel tubing and had already decided to change it to clear.

No, Ido not bring the throttle back after priming.

Do you prime at full throttle? What throttle setting do you use for starting?

Instead of clicking "reply" click on "quote" in the message you are replying to.

Yes bring the throttle back after priming! This is important!

If you do not do so the fuel runs right back into the tank or fuel lines.

When you close the throttle this slows down the fuel movement preventing the fuel from siphoning back out.

Yes you prime at full throttle, then immediately bring the throttle down as you release the carb or exhaust.

Re: Throttle

Initially I adjust my linkage setups so that there is a 2-3mm opening visible in the carb with the throttle all the way DOWN but the trim set right at the middle.

Then with the plane turned on, I'll take the trim leaver on the throttle all the way up, I'll take the throttle all the way up, then prime the engine.

Once I've primed it, I'll take the throttle back down all the way, leaving the trim leaver all the way up... next I attach the glow plug ignitor and crank the engine with my starter. If fuel has reached the carb, the engine starts quickly.

Once it is running, let it sit for 30-60 seconds, especially on your first flight of the day, before bringing the throttle trim back to the middle.

BTW: To get the second "quote" box above, I cut and pasted the bracketted delimiters in this message...

No problem were always here to help. Your plug is correct the only other thing we see from time to time is if your running wild cat or magnum fuel some kind of additive they have does not agree with our engines. Again this is not a knock on wild cat or magnum just a suggestion. It does seem as if you have some kind of issue with the fuel line sometimes using a thiner fuel line helps as well. Anything that Dubro carries works real well. Lots of luck hope you get your plane off the ground soon.

Lots of good suggestions so far. With a clear line you should be able to what is going on, it may siphon either back to the tank or into the carb thus giving you a flooded engine. Another issue is your glow driver (?), the pocket battery aids are just aids and do not supply enough power to start an engine once it is on the rich side.

This is like getting a free engineering course in RC's.

One thing I failed to mention. I crashed my LT-40 and the next time I flew it the engine would cut off on take off as soon as the nose got up. Turns out the crash knocked the pickup line off inside the fuel tank (it is a Dubro tank). I fixed it but did not pay attention to the holes in the stopper when I reassembled it and as a consequence opened up the 3rd hole. Of course when I tried to crank it at the field gas came streaming out. As a quick fix one of the guys put a machine screw in the open hole and it seemed to fix the problem.

It is not leaking gas but could this be the source of my problem?

Doubtful that's the problem as long as it's not leaking. Once you are running, there is positive pressure in your tank. So if the screw is leaking, then fuel will come out. From your description, I'm just about sure that your fuel is running back down your fuel line during the prime, not letting fuel into your engine. I have an Ultra Stick that does that because the nose sits up on the stand. It takes about 15 seconds for the starter to pull fuel up through the line to get it going normally and hand priming nearly impossible. But if I tip the nose down to level, it primes well and starts in a second or two. Tank position plays a huge role in how easy your engine is to start.

Yes. You need someone with experience to check your tank & plumbing.

Hi!
Check your fuel line for air bubbles! No such thing should be seen.
Why not use the third hole in the stopper for a second clunk ...like in a Uni-flow tank!Uni-flow will deliver a more even fuel flow.

I have one that is on it's fourth airframe. Been back to TT once for a new piston and sleeve (they honored the warranty even though it was confessed up-front crash damage).

Sounds like you have a fuel feed problem. Are you covering the intake and spinning the prop a half-dozen times (no glow starter) to draw fuel up prior to starting?

I did end up putting a Perry carb on mine after I snapped the needle valve housing. Added 600 rpm up top and starts easy.

The uniflow setup does do what it says, but it also sucks fuel back into your muffler when you let off the throttle. I had mine like that for a while as a beginner and gained 3 minutes of flight time when I changed over to a standard setup. Tuning wasn't any worse either.

We're in business.

I made a couple of small changes but I think it was mostly inexperience.

I replaced the stopper in the gas tank. I opened the 3rd hole earlier when a crash knocked the fuel line off. I plugged the hole with a screw and it seemed to do the job but I replaced the stopper anyway. I replaced the fuel line with clear so I could see the fuel as I primed it. Then I used the starting procedures as outlined by OPJOSE. I just touch it with the starter and it fires off........happy days.

Except, the first time I tried to start it after fueling I flooded it. As I attached the fuel line I noticed the line was completely full.

It would seem that the engine does not need as much priming immediately after fueling if the line is already full of fuel.

Thanks to everyone for your help.