captbillj

Please help. When I throttle up on my Thunder tiger pro .46 it runs properly for a few seconds and then loses power..almost back to an idle. I have had plane damage due to aborted take-offs.

The engine is moderately new and I have had sucessful flights.

Flyboy Dave

My Feedback: (21)

....Welcome to RCU....[sm=thumbup.gif]

Your engine is most likely set too lean....open up the big needle about 1/4 turn
and see if it still dies.

FBD.

britbrat

What he said!

captbillj

The needle valve is alrady opened almost 4 turns. That seems a bit excessive already

britbrat

Yup -- that's a lot. Normally it would be 2 - 2 1/2 turns.

Another possibility is that the low speed needle is too lean, or it may be something else.


Please describe the symptoms carefully, giving as much detail as possible.

Does the engine start easily?

Does it start easily, but then die away?

Does the engine idle smoothly?

Does it run smoothly at full power once you can get there?

Will it run smoothly at 1/2 throttle or less?

When you throttle up, does it splutter & stagger to a stop, or does it stop abruptly?

If you leave the glo-heater on, will it throttle up?

Are you opening the throttle quickly, or opening it slowly?

Is the fuel fresh?

Are you using more than 15% nitro?

Are you using any nitro at all?

What size is the propeller?

Flyboy Dave

My Feedback: (21)

Open the low speed 1/4 turn. [sm=thumbup.gif]

Turk1

Blow the fuel inlet nipple on carb to clear possible partial block after removing high speed needle.

Gringo Flyer

My Feedback: (18)

I have 2 TTpro 46 and on both of them I had a similar problem. I am not sure of its exact name but the base of the high speed needle valve worked its way lose. There is a metal washer at the base that doesnt make a good seal on both of my engines and it was losing fuel around there. I put something to seal it and tightened it down and it works fine.

Mine was doing almost the exact same thing yours is. It would crank up, run OK, then lose power and sometimes deadstick.

Also 4 turns out is way to much on that engine. I think mine are around 2 turns out.

captbillj

To answer all of britbrat's questions:

engine starts easily

It starts easily and idles well

Idle is a little rough

It runs smoothly at full power fow a few seconds before losing nearly all power. When it loses power, it continues to run. After a few seconds it will run up to full power again, only to lose power again.

runs smoothly at 1/2 throttle

When throttling up, either quickly or slowly, the engine powers up nicely.

I am using 15% nitro and it is fresh

propeller is 11 x 6 as recommended

I used a 10 x 6 for the first few tankfuls of fuel as recommended.

Also,

fuel and pressure lines are new and carb was blown out

wcmorrison

My Feedback: (2)

Check the clunk please. It may be bent back into a top corner of your tank. That will let you start up and run for a while too.

As my mechanic friend says check the fuel system from stem to stern. I have had small cracks in the fuel line, stuck clunks, mal adjusted engines, crap in the high speed needle valve area, loose back plates, leaking carbs at the throat and so on.

Cheers,

Chip

loughbd

The quality control on TT engines isn't the greatest, especially the Carbs. 4 turns or more open isn't unusual. You might try looking for crud in the fuel inlet nipple. Unscrew it and look in side.

britbrat

That is simply not true. Gringo Flyer's problem is at the adjustable (rotatable) fuel inlet nipple -- the assembly simply needs to be tightened -- that is maintenance, not QA. If you let it run like that it will fret the metal gaskets.

Four turns out for the HS NV setting turns is grossly abnormal -- normal NV setting is 2 to 2-1/2 turns.

There may be a blockage in the fuel system, perhaps a partially blocked in-line filter or dirt somewhere.



I don't have time at the moment to dig into this but I will return later.

loughbd

The fact that the nipple is falling out is a perfect example of poor quality control. You will never see that on an OS or Enya engine unless someone took it apart and didn't tighten it well enough. Adjustable?? I don't think that is the word as it's not adjustable any more than head bolts or back cover bolts are adjustable. Needle valves and valves are adjustable.

britbrat

It seems to me that you haven't seen, or operated a TT 46 Pro. The nipple is adjustable for angle -- you can swivel it around the axis of the NV assembly to position the fuel inlet line where you want. If it isn't tight, it is a user issue.

I see loose bolts, back-plates, etc on every kind of engine -- OS & Enya included (especially OS in the case of back-plates). This isn't a quality issue, it is usage, or failure to do either initial, or periodic inspections.

MrMotor

Have you made sure that the carb was pushed against the "O" ring at the base of the carb before tightening the draw bar. It really sounds like you have an air leak somewhere. One other possibility is a faulty glow plug or one that is too cold causing the low speed needle to be turned in too far. If the low needle does not come all the way out of the tube at full throttle you will not be able to get the high speed needle rich enough at any setting.

britbrat

There are some conflicting things here, but it sounds like a fuel obstruction somewhere. It seems like the engine is going lean at full throttle -- but that doesn't fit with that huge 4-turns out.

At first I suspected an overly lean low-end setting, but that usually kills transitions & part-throttle operation.

Do you have an in-line filter, either on the clunk, or in the delivery line?

Have you tried changing the glo-plug?

I wonder if the rough idle is a clue -- the TT Pro usually idles like silk. An air-leak is a possibility -- check that the carb is set down tightly on the crankcase & that the carb-base O-ring isn't nicked or pinched. Also check that the carb draw-bar isn't loose.

Another possibility is that the throttle-rotor retaining screw is loose, permitting the throttle-rotor to move back & forth in the carb body.

loughbd

If all else fails, buy an OS, Enya, YS, Rossi, etc. Even an old K&B 4011 or K&B/Veco 61. Stay away from Chinese stuff. If you notice most of the questions concerning problems making an engine idle, run etc are about Chinese or Taiwanese copies of Japanese engines? It's the same at the fields I fly at. Most of the problems are from guys using Chinese engines.

That's all. I'm done.

AMA 13797

Sport_Pilot

Most problems I see on the field or from OS, especially LA engines. Most of the TT series are better runners an quality than OS. No peeley liners, no leaky needle valves, and better power.

britbrat

I've heard that silly stuff before

loughbd

Hey if nothing else, when you buy Chinese you are supporting a COMMUNIST government. I spent most of my adult life in the military working against the commies. Now we owe them more than all of Europe put together. Remember Tianamin Square??? Same bunch.

Gringo Flyer

My Feedback: (18)

The TT pro 46 is a great engine and for the price I will put it up against any sport 46 engine.

The problem with losing pressure at the nipple is bc there is a metal washer that makes the seal. After the motor has been run at the factory setting it forms a tight seal, then if you rotate the nipple it doesnt fit perfectly back on the metal washer.

Both of my engines began to lose pressure only after I had adjusted the nipple.

I wouldnt call it a defect or poor quality control, it easy to fix and just something to be aware of. Every engine has its quirks.

Other than the problem with the nipple I have never had a single deadstick with either one of my TTpro46´s after extensive run time. For $80 I think its one of the best engine values in RC... even if it is made in BIG RED

britbrat

BTW Gringo -- I've never had a leak at the nipple seal. I just tighten it up and its good to go. Maybe you managed to get a bit of grit in there.

britbrat

TT isn't made in China, it's made in Taiwan. They are our allies, in case your geography & history are a bit shaky. Just like the Japanese were the guys from across the tracks in your terms -- but that's OK -- buy OS.

loughbd

Yeah TT is made in Taiwan but all the others, ASP, Magnum Tower etc are Chinese. TT are just copies of OS. Most of the parts are interchangable. Always wondered how they got away without patent infringement lawsuits. I remember when H Shack went to Magnum (which were made by Thunder Tiger) and we got the first ones in. 25GP's. EXACT duplicate of the new OS25FP. The only oddball at first was the 44GP which didn't last long as they had serious carb problems. Oh, and the company paid about $13 for them. Sold for $44.99. Found that out during inventory.

Yup, Taiwan is our pal but why do you think the Red Chinese are building up their military?? The only country that might try to stop them from taking over Taiwan is US.

britbrat

The TT 36/40/46 Pro are original engineering.