TT36- am I doing something wrong

TT36- am I doing something wrong

Post by Derf » Wed, 31 May 2000 04:00:00



Hello all,
I have a TT36 which dies abruptly about 1/3 to 1/2 throttle. I had it
running at one time and flew about 5 tanks, but since then it just
won't keep running no matter how I mess with the low speed and high
speed needle valves. Is this the symptom of the bad low speed needle
valve? (I've sent off for a replacement and also ordered an OS 32.) At
one setting of the needle valves, it sputtered, then ran BACKWARDS.
This happened a couple of times  - what caused that? - too lean?? If I
back out the low speed to 2 turns, the engine seems to flood an is very
hard to start.
One more question- I've heard of the "pinch" test at idle and don't
know what I'm supposed to be listening for and for how long. Could
someone explain please?

thanks
derf

Sent via Deja.com http://www.deja.com/
Before you buy.

 
 
 

TT36- am I doing something wrong

Post by Cregge » Wed, 31 May 2000 04:00:00


Sometimes when trying to idle the engine at too low a speed, it will reverse
direction and run backwards. Running backwards will not be entirely
eliminated with any two-stroke glow engine, but it can be significantly
minimized by raising the idle speed a bit.

I don't know what is wrong with your engine, but if it was mine, the first
thing that I would do is to remove the carburetor and make sure that there
are no foreign objects in the high speed jet (spray bar). Having something
in the spray bar will quite often lead to the symptoms you have described. I
would perform this check before I did anything else, other than ensuring
that I had absolutely fresh fuel of a type recommended by the engine
manufacturer and a good glow plug installed.

Check the spray bar for unwanted objects and let us know what you find. Good
luck.
--
Ed Cregger


Quote:
> Hello all,
> I have a TT36 which dies abruptly about 1/3 to 1/2 throttle. I had it
> running at one time and flew about 5 tanks, but since then it just
> won't keep running no matter how I mess with the low speed and high
> speed needle valves. Is this the symptom of the bad low speed needle
> valve? (I've sent off for a replacement and also ordered an OS 32.) At
> one setting of the needle valves, it sputtered, then ran BACKWARDS.
> This happened a couple of times  - what caused that? - too lean?? If I
> back out the low speed to 2 turns, the engine seems to flood an is very
> hard to start.
> One more question- I've heard of the "pinch" test at idle and don't
> know what I'm supposed to be listening for and for how long. Could
> someone explain please?

> thanks
> derf

> Sent via Deja.com http://www.deja.com/
> Before you buy.


 
 
 

TT36- am I doing something wrong

Post by Derf » Wed, 31 May 2000 04:00:00


OK, I disassembled the whole carb - found nothing wrong that I could
tell. BTW, the reversing of engine direction occured at mid-throttle,
and not at idle. It really surprised me when i saw the rotor blades
going backwards - seemed to run ok in reverse though..
Anyway, haven't found the cause of sudden stopping at 1/3 to 1/2
throttle yet. I did change glow plugs and no difference. I think it's
just a piece of ***engine causing the problem

thanks for the reply,
derf



Quote:
> Sometimes when trying to idle the engine at too low a speed, it will
reverse
> direction and run backwards. Running backwards will not be entirely
> eliminated with any two-stroke glow engine, but it can be
significantly
> minimized by raising the idle speed a bit.

> I don't know what is wrong with your engine, but if it was mine, the
first
> thing that I would do is to remove the carburetor and make sure that
there
> are no foreign objects in the high speed jet (spray bar). Having
something
> in the spray bar will quite often lead to the symptoms you have
described. I
> would perform this check before I did anything else, other than
ensuring
> that I had absolutely fresh fuel of a type recommended by the engine
> manufacturer and a good glow plug installed.

> Check the spray bar for unwanted objects and let us know what you
find. Good
> luck.
> --
> Ed Cregger



> > Hello all,
> > I have a TT36 which dies abruptly about 1/3 to 1/2 throttle. I had
it
> > running at one time and flew about 5 tanks, but since then it just
> > won't keep running no matter how I mess with the low speed and high
> > speed needle valves. Is this the symptom of the bad low speed needle
> > valve? (I've sent off for a replacement and also ordered an OS 32.)
At
> > one setting of the needle valves, it sputtered, then ran BACKWARDS.
> > This happened a couple of times  - what caused that? - too lean??
If I
> > back out the low speed to 2 turns, the engine seems to flood an is
very
> > hard to start.
> > One more question- I've heard of the "pinch" test at idle and don't
> > know what I'm supposed to be listening for and for how long. Could
> > someone explain please?

> > thanks
> > derf

> > Sent via Deja.com http://www.FoundCollection.com/
> > Before you buy.

Sent via Deja.com http://www.FoundCollection.com/
Before you buy.
 
 
 

TT36- am I doing something wrong

Post by David Ditc » Wed, 31 May 2000 04:00:00


I just ordered the Raptor with the TT36 engine and did alot of
research.  Try to read through as many old raptor/tt36 posts as you can
find.  Here are some specific and general suggestions:
        If you are using 30%, make sure you use the shims.
        Check the clunk
        Try setting the low speed to 1 1/2 turns out (do this with the throttle
closed). And set the high speed to 2 turns (a little rich). Then
adjusting the needle settins as below.  A rich low end can hose up your
transition.
        Check your fuel filter.
        Check or just go ahead and replace your fuel tubing. I had a ferrite
chew and a fuel tubing once, ruined my day as I took off without a
thought and immediatly had to do an Auto (SUPRISE!).  Air bubbles in a
leaky fuel line or fuel tank can lean it out (needle valves will just
confuse you then).  The air bubbles will make it cut off just around
half throttle.  I just helped out an airplane flyer the other day with
this problem.  Kinked fuel line was letting in bubbles and leanin out
the engine.  It idled fine but would not transition.
        Are You using an Enya 3 or OS 8 plug?.  I personally swear by the Enya
3.

Assuming its a needle problem this should work:
Every time you adjust the high end, take the time to use the pinch test
to set the low end.  That way you will know if the problem is the high
end or not when throttling up.  If you start the high end at 2 turns,
you should be rich so a slow process of leaning it till it climbs steady
at full throttle.

The pinch test, when idle, pinch the fuel line going into the carb.  If
it revs up just slightly then its slightly rich (probably fine). If it
revs up ALOT and stays there with a slight pinch (not cutting off the
fuel entirely) then its too rich.  If it cuts off almost immediatly then
its too lean.  (this works for airplane engines also).

Let us know how it goes.

David

Quote:

> OK, I disassembled the whole carb - found nothing wrong that I could
> tell. BTW, the reversing of engine direction occured at mid-throttle,
> and not at idle. It really surprised me when i saw the rotor blades
> going backwards - seemed to run ok in reverse though..
> Anyway, haven't found the cause of sudden stopping at 1/3 to 1/2
> throttle yet. I did change glow plugs and no difference. I think it's
> just a piece of ***engine causing the problem

> thanks for the reply,
> derf



> > Sometimes when trying to idle the engine at too low a speed, it will
> reverse
> > direction and run backwards. Running backwards will not be entirely
> > eliminated with any two-stroke glow engine, but it can be
> significantly
> > minimized by raising the idle speed a bit.

> > I don't know what is wrong with your engine, but if it was mine, the
> first
> > thing that I would do is to remove the carburetor and make sure that
> there
> > are no foreign objects in the high speed jet (spray bar). Having
> something
> > in the spray bar will quite often lead to the symptoms you have
> described. I
> > would perform this check before I did anything else, other than
> ensuring
> > that I had absolutely fresh fuel of a type recommended by the engine
> > manufacturer and a good glow plug installed.

> > Check the spray bar for unwanted objects and let us know what you
> find. Good
> > luck.
> > --
> > Ed Cregger



> > > Hello all,
> > > I have a TT36 which dies abruptly about 1/3 to 1/2 throttle. I had
> it
> > > running at one time and flew about 5 tanks, but since then it just
> > > won't keep running no matter how I mess with the low speed and high
> > > speed needle valves. Is this the symptom of the bad low speed needle
> > > valve? (I've sent off for a replacement and also ordered an OS 32.)
> At
> > > one setting of the needle valves, it sputtered, then ran BACKWARDS.
> > > This happened a couple of times  - what caused that? - too lean??
> If I
> > > back out the low speed to 2 turns, the engine seems to flood an is
> very
> > > hard to start.
> > > One more question- I've heard of the "pinch" test at idle and don't
> > > know what I'm supposed to be listening for and for how long. Could
> > > someone explain please?

> > > thanks
> > > derf

> > > Sent via Deja.com http://www.FoundCollection.com/
> > > Before you buy.

> Sent via Deja.com http://www.FoundCollection.com/
> Before you buy.

 
 
 

TT36- am I doing something wrong

Post by d_wh.. » Wed, 31 May 2000 04:00:00


Hello Derv,

 IMHO, the one item that has made the biggest difference to engine
performance has been the glow plug. I have witnessed at least 5
occasions where people were fighting problems with their engines. The
latest will be a good example. A local heli pilot with about 4 gallons
of fuel through his TT-36 suddenly couldn't get it to run! It would
start fine, but would die at around 1/3 stick every darned time. He and
one of our local engine gurus started trying everything. Plug,
different fuel, flushed out the carb, different needle settings, etc.
After they had tried everything once, they decided to start all over
again. They were out of plugs so I loaned them an Enya #3. The engine
ran perfectly through 3 tanks of fuel before we all went home that day!
Like I said before, this has happened at least 5 times here. The TT-36
seems to LOVE the Enya #3 plug. I would suggest you try one as soon as
possible.. Be sure  and let me know the results, regardless of how it
turns out. Remember, start all over again with the main needle at 2 1/2
turns out and the low needle at 1 1/2 turns out. Only adjust  each
about 1/8 of a turn at a time until you get it right.

 My favorite method for adjusting the idle needle is the old "pinch the
fuel line" method. That is where you start the engine and let it warm
up for 30 seconds or so. Then, pinch the fuel line hard enough to shut
off fuel flow and hold it until the engine dies. If the engine speeds
up quite a bit before dieing, it is too rich. Turn the idle needle in
1/8 turn and try again. If the engine quits without speeding up you are
too lean. Turn the idle needle out 1/8 turn and try again. If the
engine speeds up slightly and then dies you are right on.  The type of
fuel does not seem to make much difference. We have some people running
15% Morgan, others running 30% morgan (without the shim), some with 15%
blend (castor/synthetic), and others using 10% all castor. It all seems
to run fine as long as they use the Enya #3 plug... When I first got my
Raptor, I used up my remaining supply of 12.5% morgan blend and didn't
have any trouble with it.

 As for "kicking back" and then running backwards, I have never seen
this happen (been playing with these things for over 40 years) unless
the engine is at or near idle.

Later;
D.W.



Quote:
> Hello all,
> I have a TT36 which dies abruptly about 1/3 to 1/2 throttle. I had it
> running at one time and flew about 5 tanks, but since then it just
> won't keep running no matter how I mess with the low speed and high
> speed needle valves. Is this the symptom of the bad low speed needle
> valve? (I've sent off for a replacement and also ordered an OS 32.) At
> one setting of the needle valves, it sputtered, then ran BACKWARDS.
> This happened a couple of times  - what caused that? - too lean?? If I
> back out the low speed to 2 turns, the engine seems to flood an is
very
> hard to start.
> One more question- I've heard of the "pinch" test at idle and don't
> know what I'm supposed to be listening for and for how long. Could
> someone explain please?

> thanks
> derf

> Sent via Deja.com http://www.deja.com/
> Before you buy.

Sent via Deja.com http://www.deja.com/
Before you buy.
 
 
 

TT36- am I doing something wrong

Post by Bill » Wed, 31 May 2000 04:00:00


Quote:

> OK, I disassembled the whole carb - found nothing wrong that I could
> tell. BTW, the reversing of engine direction occured at mid-throttle,
> and not at idle. It really surprised me when i saw the rotor blades
> going backwards - seemed to run ok in reverse though..
> Anyway, haven't found the cause of sudden stopping at 1/3 to 1/2
> throttle yet. I did change glow plugs and no difference. I think it's
> just a piece of ***engine causing the problem

> thanks for the reply,
> derf

Based on your original post, plus this followup, I suspect two things...

1) your mixture is too rich, especially in the mid-range

2) you did not install the head shim that is now shipped with that
engine

I have one of these in my new "RaptErgo" (Raptor with Ergo body) and
from the moment I first started it up and got the mixture close, it has
run like a dream! Yesterday I was out at the local heli field for the
first time with it and I was the ONLY one not tinkering with their
engine!!! It always starts on the first try and since changing to fresh
fuel has NEVER quit (the first two or three tanks were on old fuel and
it wouldn't run without the glow ignitor attached). I really do not
think the engine is a piece of crap, but many guys are not installing
the head shim, and I personally believe that is a big cause of their
problems.
--
Bill
Modern Images

http://www.FoundCollection.com/~wrainey/  Bill's Homepage
http://www.FoundCollection.com/; Modern Images Website

 
 
 

TT36- am I doing something wrong

Post by Cregge » Thu, 01 Jun 2000 04:00:00


No, Thunder Tiger does not make piece of whatever engines. Granted, they are
not as refined as OS, Enya or Webra, but they are not as expensive either.
However, I couldn't blame you for switching to an OS if what you want to do
is fly and not tinker.

Reversing at mid throttle is something that I have never heard of before,
UNLESS the engine's low speed needle was adjusted for a grossly rich
condition. Whatever the cause, I hope you remedy the problem.
--
Ed Cregger


Quote:
> OK, I disassembled the whole carb - found nothing wrong that I could
> tell. BTW, the reversing of engine direction occured at mid-throttle,
> and not at idle. It really surprised me when i saw the rotor blades
> going backwards - seemed to run ok in reverse though..
> Anyway, haven't found the cause of sudden stopping at 1/3 to 1/2
> throttle yet. I did change glow plugs and no difference. I think it's
> just a piece of ***engine causing the problem

> thanks for the reply,
> derf



> > Sometimes when trying to idle the engine at too low a speed, it will
> reverse
> > direction and run backwards. Running backwards will not be entirely
> > eliminated with any two-stroke glow engine, but it can be
> significantly
> > minimized by raising the idle speed a bit.

> > I don't know what is wrong with your engine, but if it was mine, the
> first
> > thing that I would do is to remove the carburetor and make sure that
> there
> > are no foreign objects in the high speed jet (spray bar). Having
> something
> > in the spray bar will quite often lead to the symptoms you have
> described. I
> > would perform this check before I did anything else, other than
> ensuring
> > that I had absolutely fresh fuel of a type recommended by the engine
> > manufacturer and a good glow plug installed.

> > Check the spray bar for unwanted objects and let us know what you
> find. Good
> > luck.
> > --
> > Ed Cregger



> > > Hello all,
> > > I have a TT36 which dies abruptly about 1/3 to 1/2 throttle. I had
> it
> > > running at one time and flew about 5 tanks, but since then it just
> > > won't keep running no matter how I mess with the low speed and high
> > > speed needle valves. Is this the symptom of the bad low speed needle
> > > valve? (I've sent off for a replacement and also ordered an OS 32.)
> At
> > > one setting of the needle valves, it sputtered, then ran BACKWARDS.
> > > This happened a couple of times  - what caused that? - too lean??
> If I
> > > back out the low speed to 2 turns, the engine seems to flood an is
> very
> > > hard to start.
> > > One more question- I've heard of the "pinch" test at idle and don't
> > > know what I'm supposed to be listening for and for how long. Could
> > > someone explain please?

> > > thanks
> > > derf

> > > Sent via Deja.com http://www.FoundCollection.com/
> > > Before you buy.

> Sent via Deja.com http://www.FoundCollection.com/
> Before you buy.

 
 
 

TT36- am I doing something wrong

Post by Cregge » Thu, 01 Jun 2000 04:00:00


Thanks for the reminder on the head shim, Bill.

My ARF Raptor did not come with any engine manual, head shim or any other
material related to the engine. I guess I'm gonna have to see what TT has to
offer on a personal basis.
--
Ed Cregger


Quote:

> > OK, I disassembled the whole carb - found nothing wrong that I could
> > tell. BTW, the reversing of engine direction occured at mid-throttle,
> > and not at idle. It really surprised me when i saw the rotor blades
> > going backwards - seemed to run ok in reverse though..
> > Anyway, haven't found the cause of sudden stopping at 1/3 to 1/2
> > throttle yet. I did change glow plugs and no difference. I think it's
> > just a piece of ***engine causing the problem

> > thanks for the reply,
> > derf

> Based on your original post, plus this followup, I suspect two things...

> 1) your mixture is too rich, especially in the mid-range

> 2) you did not install the head shim that is now shipped with that
> engine

> I have one of these in my new "RaptErgo" (Raptor with Ergo body) and
> from the moment I first started it up and got the mixture close, it has
> run like a dream! Yesterday I was out at the local heli field for the
> first time with it and I was the ONLY one not tinkering with their
> engine!!! It always starts on the first try and since changing to fresh
> fuel has NEVER quit (the first two or three tanks were on old fuel and
> it wouldn't run without the glow ignitor attached). I really do not
> think the engine is a piece of crap, but many guys are not installing
> the head shim, and I personally believe that is a big cause of their
> problems.
> --
> Bill
> Modern Images

> http://www.FoundCollection.com/~wrainey/  Bill's Homepage
> http://www.FoundCollection.com/; Modern Images Website

 
 
 

TT36- am I doing something wrong

Post by RFisk891 » Thu, 01 Jun 2000 04:00:00


I don't have to do any tinkering with my TT36.   I'm running CP 30% with the
head
shim,  and an Enya #3. There is a rich spot
about 1/3 throttle that gets better once you
have some fuel through it.  I had a friend
help adjust the idle mixture,  and it has
been trouble free.

 Bob

 
 
 

TT36- am I doing something wrong

Post by David Lodg » Thu, 01 Jun 2000 04:00:00


Quote:

>Based on your original post, plus this followup, I suspect two things...

>1) your mixture is too rich, especially in the mid-range

I'd second that. The TT36 is prone to a rich 1/4-mid range

-------------------------------------------------------------------
#include<disclaimer.h> Opinions are mine and not those of my company

David Lodge,

http://www.cherrybank.co.uk