Re: Super Tigre Carb Tuning

"3for3" <mor_rc@[EMAIL PROTECTED]
> wrote in message 
news:aB2bk.3284$vn7.1167@[EMAIL PROTECTED]
> Hi Ted,
> My experience with the 5 ST engines that I have owned/own has been
varied.
> I have never experienced that moving the spray bar has made a difference

> in the performance of the Super Tigre engines. I have also tried placing
a 
> brass ferral in the carb throat to decrease the intake diameter with no 
> positive effect.
> Today I have two G-51 that are three years old and they both misbehave
on 
> a regular basis. One is on a Seamaster and I have the low needle at 8
plus 
> turns out to keep the low end and mid transition from going lean. The 
> other G-51 is on a trainer and is always full of surprises. I don't know

> if these engines are sensitive to barometric pressure or the alignment
of 
> the planets. Some days they run very acceptable and other days they are 
> threatening to stall during transitions.
> I have a G-45 and a 40 (Italian made) that run like clocks with no
issues 
> what so ever.
> I did own ( and now returned to Tower Hobbies with full refund) a 61
size 
> engine that ate three planes.
>
> I see others peoples responses indicate that they need a lot of
break-in. 
> If more that three gallons of fuel does not qualify for break-in, then I

> need to sell these G51's to some unsuspecting person on Ebay and go buy 
> some magnum XLS-46's.
> I have not replaced my temperamental ST G-51's because I am frugal and I

> like a dead stick challenge at least twice a week. If I were to purchase

> new engines I would not purchase a ST again. I own OS, GMS, Magnum, Jett

> and Weston engines and do not have the trouble that I have with the two 
> G-51's.
>
> On a side thought, maybe the issue with the G-51's are a quality issue 
> with machined surface tolerances and are on the margin of acceptable 
> dimensions.
> Does anybody know what happens when the crank intake area under the carb

> opening and the inside wall of the crank case get leaky?
>
> Thanks for reading
> RCS
>
> "Ted" <tkennedy63@[EMAIL PROTECTED]
> wrote in message 
>
news:b975c373-fd62-4388-8d65-3ad1457d1364@[EMAIL PROTECTED]
>>I am having a bit of a problem getting my ST 51 to run smoothly. I
>> have had STs before so I know you have a delicate balance between the
>> low end and high end before you get it just right. I recall reading
>> somewhere that the position of the spray bar is very critical as well.
>> Has anyone also heard of this? And what position would be ideal? Most
>> engines like it pointed straight down but I seem to think the STs
>> prefer a little upward thrust of the spray so if you are looking from
>> the needle valve side it would be pointed around 4 o'clock. Any
>> thoughts or experience on this? Many thanks.
>>
>> Ted

------------

I'm going to treat this subject as though there are folks reading my 
response is brand new to the hobby - not you.

The first thing I would do is to compare the ST.51 engines' features to 
those of the engines you own that run well. Are they ringed? The ST.51 is
a 
ringed engine. Are you using the same glow plugs in all of your good
running 
engines and is this the same type of glow plug that you are using in your 
G.51 engines? Fuel? Prop sizes for equal and near displacements? Inverted 
engine installation?

Can you see where I'm going with this? I realize that you have probably 
already been through this routine, so forgive me for being simplistic, but

many times the things that are causing us grief are simplistic.

If your other ST engines are running great and are nearly the same size, 
might not their carbs switch with your problematic .51 engines? Might be 
worth a try.

A ringed engine can have quirks in running that are caused by a defective 
ring, or a defective ring slot in the piston. Changing a ring and
inspecting 
the ring slot/groove is an easy process and is one that might yield an 
answer to your problem. I can think of nothing about the ST.51 design that

is problematic on a regular basis.

I am not telling you that I don't believe you or that you are
hallucinating. 
I believe you. Let's get to the bottom of this. Now it is time for you to 
answer some of the above questions, if you please.

Ed Cregger