hi

i have a thunder tiger 46 pro with enya glow plug 3,swing a 11X6 prop and running on 10 nitro.When i set the engine (idle needle and high speed needle ) and get it tuned then I refuled or after a flight the engine loses its idle setting and start to quit and jams on TDC?

How much running time does it have? I find that TT engines are very tight when new (for ABN) engines. Mine have taken from 1/2 to 1 gallon to loosen up for reliable running.

3 and half years old

Check the idle screw, look at the o-ring, could be damagend, and it makes the screw to turn into the housing.<div>
</div><div>Saludos, </div><div>
</div><div>jorge</div>

i replaced all the o ring and the screw is very tight :S

Do you use an electric starter? Have you ever accidentally flooded the engine while starting it? The fact that a 2yr old engine is jamming at TDC makes me wonder if the conrod is slightly bent.

David

Maybe your not using enough oil in your blend.

Pull the rear plate and check the rod. I had one seize once and break the rod. It started out losing rpm, then stopped dead and threw the prop.

Check the seal of the backplate, the seal of the main needle, the seal of the carb in the crankcase, the seal of the carb barrel... another possible problem could be excessive leakage on the front bearing (worn out front bearing)??

<p class="MsoNormal" style="margin: 0cm 0cm 0pt"><font size="3"><font face="Times New Roman">today I noticed that when it stops(idle) it loses its compression<span style="mso-spacerun: yes"> </span><span style="mso-spacerun: yes"></span></font></font></p>

I don't know what the answer is.  My TT 46 pro is slick as a whistle, the wind will move the prop around.  But there is still a pinch fit at the top.  And it runs great.  I have had a set of bearings for it but no need to change them yet.  I do use blended fuel and always make sure there is
Castor in the mix.

Cheers,

Chip

Hi!
Sounds as if you just run it too lean!
Open the high speed needle some!

You could be flooding the engine with fuel when you fill the tank. It may be enough to prime a cold engine, but too much for a warm engine. Of course this depends on you tank plumbing and filling technique.

</p><div><span style="font-size: larger">I dissembled the engine today and I discovered that there are scratcheson the liner and the piston. About 2 years ago I had to replaced the bearings (both of them) and there was a scratch on the piston(only justa scratch)and liner probably by time the scratches increase somehow :S</span></div>

Scratches are pretty normal in our engines, as long as they are not so deep... if the compression is good, there is nothing to worry about.

The problem must be somewhere between:

1. Tank and it's associated components.
2. Seal problem (Backplate/needles/carb throat/front bearing)
</p>

It is also normal that the engine looses it's compression when hot, it's because of the liner's natur, that expands in the upper part.</p>

You haven't said anything about the glow plug.... have you checked it?, it would be a good thing anyway to put a new plug in it, fresh fuel... I bad plug can drive you nuts trying to finde the problem...everything else may be ok, but if the plug is damaged (coil with excesive carbon, not bright etc.. that the engine starts and that the plug glows doesn't mean that its good)</p>

and if you are not sure about the needle settings, than reset it to "factory settings"... 1.5mm gap between the spray bar and the mixture screw is a good starting point.</p>

Saludos,</p>

</p>

Jorge</p>

when i put my finger nail in the <font size="2">scratch i get a good grip

new pics</font></p>

note the pic on your right : (where the screw driver is potining ) when i put my finger on it is very rough.

Looks like you need a new cylinder and piston. You must have gotten something hard in there. Check your rear bearing as well. The carriages have been know to come apart in some of the TT's. You can a set of bearings from RC Bearings pretty cheap and they work great. Could be yours came apart and scored the cylinder. Could be dirt or sand too. I think these engines are worth rebuilding myself.

Hi Alan

That the glow plug glows doesn't mean that the glow plug is in good condition...

The glow plugs aren't good anymore when things like the following occur:

1. Carbon buildup
2. Distorted filament
3. Filament looses his bright (when cold, the platinum filament is not shiny)
3. The filament is melted and take another shape...

By the way...from the pictures I can't see much...

About the scratches....if the engines holds compression...it's ok....I would say that if the engine runs at all, no worries... I'm sure that your problem is not related to the piston/sleeve fit....

Make sure you assemble the liner and the piston in the same way they were...

Saludos,

Jorge</p>

i have a second TT 46 pro and it has greater compression then this one

That scratch is not likely to cause a problem.  I have had deeper scratchs and the engine ran fine.  As estradajae said if the engine has compression it is fine.  Besides your engine doesn't sound like an engine with poor compression.  That would be hard to start hot, poor idle (not just after a flight), and low power.  However, if the scratch is recent it could be causing the piston to jam a bit, extra run time may get rid of that problem.  IMO it is something causing your restarts to be too rich.

It would leak past the scratch, but I doubt it would leak fast enough to be a problem. If it has enough to start hot easily then it has enough compression.

<p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><span style="mso-ansi-language: DA"><font size="3"><font face="Times New Roman">Hi there.

</p></font></font></span></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><span style="mso-ansi-language: DA">

<font size="3" face="Times New Roman"> </font></p></span></p><p style="MARGIN: 0cm 0cm 0pt" class="MsoNormal"><span lang="EN-GB"><font size="3" face="Times New Roman">Is it right, that you can run the scratched engine (low compression), with fuel made with 20% castor oil? Set the HSN too lean, to get the engine temperature too high for some minutes. Because of the extreme heat, the castor will make a thick hard surface (</font></span><span style="FONT-SIZE: 10pt; FONT-FAMILY: Verdana; mso-bidi-font-family: Arial" lang="EN-GB"><span style="COLOR: black; TEXT-DECORATION: none; text-underline: none">Carbon</span> buildup?</span><span lang="EN-GB"><font size="3" face="Times New Roman">) in all scratches, so the compression will return.</font></span></p>

I've read here from someone who did that succesfully, but haven't tryed it myself...

I run always castor oil.... und despite the mess, I think I still like it more...

I have a 4 stroke engine, yesterday at the field was pretty warm, and I changed from a fuel with castor to a fuel with synthetic to make a test....as soon as the fuel with castor was used (in the line I think)...the engine dropped about 300 RPM....and I think that the fuel with synthetic wasn't so good at high temps outside, the one with castor worked as usual. The last weekend I used the same fuel with synthetic, and it worked well, I couldn't tell the difference between the two...but it wasn't so warm... I don't intend to start again (128319273981273 times here) a discussion about the castor/synthetic oils....but it seems to me that in all the cases, that castor will help to seal better.

Saludos,

Jorge