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help with a super tigre s 61


daniel barton
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basically i cant get the engine to run the way it should and starting it is a pain aswell.

prop: 13x8 master screw

fuel: model techniks 20%but im changing to 10% in a week or so

plug: size 8 and its a fairly long shank on it.

the engine itself is second hand and had a deep clean before i bought it.

what else would you like to know

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Assuming that you have compression and a glow it should at least fire.

Connect a clean fuel line to the carburetter, close the throttle and blow through it. Wind in the slow-running jet until you can't blow through it, then unwind it so that you can just blow through the tube. That's your slow running roughly set.If you cannot blow through it at all the carburetter is blocked. Take the carburetter off , dismantle it and clean it in some kind of solvent. Unwind the main jet say 4 turns from fully closed. Do not use excessive pressure when closing either needle. Connect to a fuel tank with the centre line of the fuel tank level with the carburetter and fill the tank.

Fit the propeller and spinner, open the throttle fully and holding a finger over the carburetter air intake, turn the engine over 3-4 times. This will draw fuel into the engine. Adjust the throttle so that it's only just open then apply current to the glow plug either with glow leads or a glow clip and turn the engine over on the starter motor.

It will probably run. If it doesn't, get back to us.

You'd be better off joining a club.smiley

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13*8 sounds a bit much to me, I'd have thought a 12*6 or 12*7 would be nearer the mark for an S61. I can run a 13*8" prop on an OS61SF or FX but I believe they were designed for lower revs while the S model STs being an older generation were happier revving a bit higher.

I read somewhere that STs can respond well with OS F plugs.

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Posted by daniel barton on 27/11/2012 18:12:16:

fuel: model techniks 20%but im changing to 10% in a week or so

No! No! No! Super-Tigres should be run on STRAIGHT fuel - NO nitro!

You *might* get away with 5%, but for best results run it on STRAIGHT! On 20% it is unlikely to run at all, let alone properly!

Tiggies use long reach plugs, and whilst they will run on OS no8's, for best results use a hot long reach plug. Mick Wilshere is still around and will still service Tiggies. Contact Motors & Rotors if you need it serviced.

I've used Tiggies for years, and can confirm from first hand experience that trying to get them running on nitro is the equivalent of filling your diesel car with petrol!

--

Pete

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Super Tigre carburetors have been maligned by some modelers as being hard to adjust and too finicky. My experience with Super Tigre engines has taught me to make any carb adjustments in very small increments, and once they are properly set they stay that way. If you are used to cranking a needle 1/4 to 1/2 turn to try and improve a condition, you will never get a Super Tigre carb adjusted properly. I have had properly adjusted Super Tigre carburetors go from too rich to too lean in less than a quarter turn of the low speed needle.

To set up this carburetor you will need a short piece (1 foot) of clean fuel tubing.


First the idle speed adjustment screw needs to be adjusted so that the throttle barrel is open about the diameter of a modeling T pin. Later after the idle and mixture has stabilized and the engine is mounted in the aircraft this setting can be backed off so that the throttle barrel will close all the way with low throttle and low throttle trim to kill the engine.

Open the throttle barrel wide open, then with the length of clean fuel tubing attached to the fuel inlet nipple, blow through the tubing. Screw the high-speed needle in until you hear no air escaping. Now open the high-speed needle 2-1/2 turns.


Now with the throttle barrel at the previously established closed position, gently blow through the tubing. Adjust the low speed needle in until you can barely hear air escaping. Now open the low speed needle 1/2 turn from this position.

Bear in mind if you change the position of the throttle stop you will have to reset the low speed needle. Also the setting on the high-speed needle will affect the low speed transition. I have had the best luck trying to get a reliable idle and good transition with brand new Super Tigre engines after they are properly broken in. I have run as much two gallons of fuel through Super Tigre ringed engines before the idle and transition stabilized to an acceptable level. The breaking in of a Super Tigre engine is time consuming and if not rushed, will reward you with an engine that should almost last a lifetime.


With the engine mounted on your aircraft it is time to start it. Fill the fuel tank and open the carburetor wide open. With your finger over the carburetor throat (and glow plug driver NOT CONNECTED) bring the prop up on the compression stroke and slowly turn it through one revolution. You should see fuel flow into the fuel line and into the carburetor, flip through about two more revolutions with your finger over the throat. If when you remove your finger from the carburetor throat and the fuel in the fuel line flows back into the tank, this could be an indication that your fuel tank is too low relative to the carburetor’s centerline. Go to low throttle, high throttle trim on your radio. Connect the glow driver and with a chicken stick flip the prop through until the engine starts. Some of the hotter Super Tigre engines that I have had had a propensity to start in reverse. If this is the case try rotating the prop backwards against compression and letting it pop back. Usually the engine will start and run in the proper direction. If the engine starts and will idle fairly well, let it run for a minute or two to allow the engine to come up to operating temperature. Advance the throttle slowly to wide open. Listen to the engine and determine if it's four stroking or two stroking. If it's four stroking screw in the high-speed needle until the engine transitions to two stroke. Now open the high-speed needle until the engine just goes into four stroke. Back off the throttle to idle and have a helper hold the aircraft. With the helper holding the aircraft advance the throttle to wide open. Have your helper point the nose of the aircraft to the sky. If the engine speeds up to a stable two stroke, the high-speed needle is set properly. If the engine is new, I generally open the high-speed needle about 1/8th turn additional to ensure a rich high end until it's broken in.

Once the high-speed needle is set, return the aircraft to the level position and set the throttle to low throttle/high trim. If the engine is idling let it idle a few seconds then slowly advance the throttle. If the engine burbles, and it may spit fuel out the throat, it's too rich. If this is the case, close (clockwise) the low speed needle about 1/8th turn. Run the engine to full throttle to clear it out then return to idle for 10 to 20 seconds then slowly advance the throttle. Repeat the above procedure until you have a smooth throttle transition. If the engine sags and hesitates with no burbling it means the low speed needle is too lean. Open (counter clockwise) the low speed needle about 1/8th turn and try it again. This is the most time consuming part of adjusting any model engine carburetor so be patient. Once you are satisfied with the idle and transition return the throttle to wide open and recheck the high speed setting as per the previously outlined method and make the necessary small changes, then fly.

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  • 2 weeks later...

well i aint sure how i done it tbh, but i will explain as best as i can.

firstly i set the high end needle back to factory by screwing it fully in and then 4 turns out (3 to get her started)

then with the low end needle, i simply screwed it fully in and 1 and a half turns out (ill explain the setting further later on.)

then as i blew as hard as i could on the exhaust pipe and filled up the carb (i know your all thinking that i flooded the carb, but ironically this really did help)

with my finger over the carb, i gently turned the prop 3 times and also held the prop on the vacuum point ( where u can here fuel being drawn into the engine) for a few seconds.

then i connected the glow starter and flicked the prop twice, she tried to fire at this point but couldnt quite start so i unscrewed the low end needle by 1/8th turn at a time, then spin the prop another few times and if she didnt fire, then id do another turn, at 2 and a half turns, i stopped with the low end needle and started on the top end as follows:

with the setting set at 4 turns out, i turned the needle (1/4 turn at a time) in and finally at 3 turns in, the engine fired up and started nicely and now all i have to do is tweek the needles to find the optimum running point, but i have to do some servo adjustments before this anyway as i cant open the throttle fully atm.

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  • 8 years later...

Just moving the needle someway Daniel can dislodge gunk blocking fuel or airflow.

So your moving those in and out probably did the trick.

Change that 13 x 8 prop before you fly though, as advised earlier, this is overpropped.

having set up on the 13 x 8, you will need a little retuning on a 12 x 6

Edited By Denis Watkins on 30/01/2021 21:53:57

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My memory of running an S61 on a 12X6 is that it goes like stink but the prop noise is horrendous! What I also seem to remember is if the transition from idle is poor you can turn the spray bar slightly to adjust it.
I had an aircraft in the loft/various sheds for nearly twenty years and when I re-commissioned it only slight adjustment was needed to the carb. I bought a second S61 at a club sale for £3. I love them but as I say, they can be tricky to keep relatively quiet. Both mine are Italian built with detachable front housings.

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