Thunder Tiger 1.20 Problem....Help!!
 

I have this engine which is pretty much brand new... runs good at full throttle ....when I go to mid range or idle she goes dead stick. I have adjusted top and bottom end and started over and over again.....????? Also I have to take off filthy rich or it leans out during flight. I have heard that there is a new carb that fixes the problem...does anyone have experience with this engine??????? Appreciate someones experience here !!

TT120
 

What muffler are you using? This eng. is sensitve to muffler pressure, or lack of with the some pitts.
I had some problems with mine with a 24oz tank.
Nose up got lean, nose down got real rich. Full tank was rich, near empty got lean.
I put on a Perry pump, now it's perfect.

Kirk

Thunder Tiger 1.20 Problem....Help!!
 

Just went through some of these same problems with my TT 120. I ran it with Omega 5% and extra castor added on the bench, using the factory muffler, and it would follow the needle valve very well. (Four-cycle rich at maybe 2 or 2 1/2 turns open). Then I put it on my new Aeroworks Edge 540, using a Slimline Pitts style muffler and APC 16X8 prop, 10% Omega. It ran very strong, but could not be richened at all. That leaves me very uncomfortable..... So, I plugged one of the two stingers on the muffler. Now it could be richened, but on this airplane, needing all the power it can provide, the power was off enough to make the airplane somewhat "doggy".

I tapped the backplate and put a Perry P-30 pump (now Conley) on the firewall behind the engine head. Now it runs strong, and can be richened to a four-cycle at 2 turns open. This is the fifth or sixth Perry I am using and they all work well. I think this would solve your problems. And BTW, I don't set the pumps for maximum pressure. They are not critical. Good luck!

Clair Sieverling

Thunder Tger 1.20 problem
 

Hi Kirk...thanks for the input !!! The stock muffler is back on it and one of the two exhaust ports is now closed. I think the pump might be the way to go...when I prime the engine before liting it up you can see the fuel go back to the tank...!!!
Alan

Thunder Tiger 1.20 Problem....Help!!
 

Hi Claire, Thanks for the response !! I am running Wildcat 15% nitro but I do add 2 oz of castor oil to the already existing synthetic - castor mix. I will go with the pump...have you heard anything about a new carb they are making for this engine??
Alan

Thunder Tiger 1.20 Problem....Help!!
 

No, I haven't heard anything about a new carb.....my engine was purchased in Feb. 2001 so I assume it would have the old carb. The carb seems to be fine now that I have the combo right.

Thunder Tiger 1.20 Problem....Help!!
 

It sounds like a few of you are having some problem drawing fuel, and I hate to see you drilling into the backplate to install a pump that you may not need. Check to see that your tank level is inline with the Carb, and not high or low. The centerline running horizontally thru the tank, should be located about 1/4" - 3/8" below the spray bar.

Both of mine have been running beautifully for years, with none of the symptoms described above. I think that you might be having plumbing problems. And I never heard anything about a new Carb, nor does it need one.

Jim

Thunder Tiger 1.20 Problem....Help!!
 

Both of my Thunder Tiger 1.20 Pro engines came from the factory with the backplates tapped and plugged with a screw. I wonder when they changed that?

I would have used the Cline Regulator rather than the Perry Pump. Still, whatever works...

TT120
 

No plumbing problems here --
Mine ran great on the first two planes with stock muffler.
The Bisson pitts on the latest caused the fuel delivery problems.
I played with plugging exhaust but the pump is perfectly consistent full to empty no matter what the attitude.
Without a pump, it will never be.
I bought new about 10 years ago and it had the rear cover drilled and tapped for fitting.
Never heard of an upgrade carb.

Kirk

Thunder Tiger 1.20 Problem....Help!!
 

Mine came with the backplate already drilled and tapped, and a pressure nipple furnished, so no big deal. It is simply a problem of too little muffler pressure with a two-stinger pitts style muffler. The Perry pump solved the problem as it does with my Webra 120s (2) and several others. The Cline would be just as good also.

Mine also has very low compression, which would seem to me to reduce the ability to suck fuel somewhat. But it runs strong in the air, and that is all that matters!

Thunder Tiger 1.20 Problem....Help!!
 

Jim, Ed, thanks for dropping in....plumbing not the problem. All looks good there, My engine also came pre-drilled on the back plate with a pressure nipple...... There is definitley a pressure problem....... !!!

Thunder Tiger 1.20 Problem....Help!!
 

OK on the pressure problem. Please keep us updated on what you find. I may need that kind of help someday.

Thunder Tiger 1.20 Solution !!!!!!
 

Problem solved !!!!! At the urging of some of you I went out and spent $35.00 bucks on a perry pump.....Wow Like night and day !! I then unplugged the second stinger coming out of my muffler which I had plugged to create more pressure.....even better with more r.pm.... I am spinning a 15x8 prop and she pulls my Ultimate Bipe straight up !!!!
This plane will now sit on the ground and idle forever at a very low idle... after more than a few minutes I wack the throttle and she hits hard...!! In flight same results..!!! Idle to mid to full..beautiful transition !!!
I would encourage anyone who has one of these to put on a pump and enjoy flyin again !!!!
Thanks
Alan

Thunder Tiger 1.20 Problem....Help!!
 

Can I say "I told ya so?" Glad you got the same results I have gotten with the Perry Pumps!

Clair Sieverling
AMA 15654

Thunder Tiger 1.20 Problem....Help!!
 

Is a cline regulator a pump and regulator......... and is there any regulating going on with a Perry pump?

Thunder Tiger 1.20 Problem....Help!!
 

I have been running a VP-30 Perry pump on mine. The engine is on a World Models 1.20-size Extra 300. I have the tank mounted near the CG, so there's about 15" of fuel line from the tank to the carb. I'm using a BCM pitts muffler with NO pressure line running to the tank as per Perry instructions.

I had to lean out the high-end needle considerably to get the engine to perform with the pump. I also leaned the low-end for a consistent idle. In any attitude, the engine runs consistently at high RPM. The midrange is rich which is obvious from the burbling during mid-to-high transitions. I tried adjusting the pump to correct this, but it seemed to make very little difference. I am planning on purchasing the Perry carb (pump version) and hopefully this will solve the problem.

-Tom

Osborn MO
 

Where's Osborn Missouri?

Thunder Tiger 1.20 Problem....Help!!
 

Osborn is approx 60 miles North of Kansas City...right smack dab in the middle of nowhere! The upside to this is that there is plenty of available farmland around. Our club field (Cameron, MO) is everything that a person could ask for...flat and WIDE OPEN! There's not a tree within (estimated) 1500 feet of the runway. However, there is an electric fence at the north end that can provide some 'entertainment'! :)

-Tom

Thunder Tiger 1.20 Problem....Help!!
 

Hey Tom, I played around with the pump and High end needle considerably and found the following...The pump is close to maximum open setting...my high end needle is only open 9/10th of one turn...!!!! I was not comfortable with that at first however...I have less trouble with gurgling at low end/midrange and my transition is good to full throttle.. Have no trouble richening her up at all.... !! n At first I thought I needed to turn the pump pressure down so that I could open the high end needle more but
this seems to be the ideal setting..!!!
I would like everyone elses opinion on this..!
Thanks Alan

Thunder Tiger 1.20 Problem....Help!!
 

Alan, 9/10ths of a turn sounds about right where mine is opened to. I need to play around with the low-end needle some more...but I don't have an access hole for it through the cowl. Time to fire up the dremel!

-Tom

Cline
 

I ran mine with a Cline fuel delivery system and never had a problem. The Cline is a very simple, small and reliable set up. Check it out at www.billsroom.com

Thunder Tiger 1.20 Problem....Help!!
 

Hi,

I have recently bought one of these engines and its driving me nuts. The 1st problem was that it had a head gasket/shim missing. Having sorted that, I'm running with a perry pump but the 1/2 to full throttle pickup is lousy - takes around 5 to 10 seconds to get going. Idle is spot on - it will keep going until the fuel runs out, as it the top end (once it gets going). Low to 1/2 throttle is also OK. I can't seem to do anything to get the pickup sorted in the upper range. Fuel used is 5% nitro, 20% castor. The engine also seems quite sensitive to the low end needle setting, but very insensitive to the high end setting (when richening up).

I have set up many engines before without this sort of problem, and have a TT46 pro which is excellent.

Has anyone got any ideas?

Mark

Thunder Tiger 1.20 Problem....Help!!
 

go with the Cline ... it's well worth the money. My 1.20 Pro is a great and reliable engine.

Thunder Tiger 1.20 Problem....Help!!
 

Hi,

one more thing on the TT120 - does anyone know what is the difference between the old and new carbs for this engine?

Mark

Thunder Tiger 1.20 Problem....Help!!
 

Hey Mark...I use a perry pump cost 35 bucks,,,works great. The Cline works good too.....The fuel you are using is too too weak and too much oil.....get rid of it.....At full throttle your not burning anything...it's choking .....I use 15% Nitro Wildcat with
16 % Castor/Synthetic blend oil with a little added castor. Or just go buy a gallon of 15% Cool power...The pump is set open high with the high end needle only open 9/10 of a turn.. I have heard about the new carb but no one seems to be able yo tell me anything either !!! This should do ya..let me know how it works out.
Alan