Aviator 25

I have a new Super Tiger GS-40. I bench ran the engine for break in, and while running the engine I found it hard to tune. I thought that it just might not be broke in enough so I ran through about 6 tanks of fuel. After braking it in I tried tuning the engine but it keeps surging and missing. I checked the tank and fuel lines, I took the carb apart and checked for leaks, I checked the needle valve for leaks, I tried other fuels, and tried changing the glow plug. I just can't get this engine to run right.
It's my first Super Tiger. Is this common with these engines?

Dr1Driver

No. STS are VERY reliable and user-friendly engines. STs sometiems take longer than you other brands to break in. If you ran it reasonably lean during those 6 tanks, that should be enough. Remember, an ABC/N engnie needs to get up to operating temperature to properly break in.

Let's get the low end properly adjusted. There's a special trick that ALWAYS works with STs.

With the engine NOT running, place a short piece of fuel tubing on the inlet.
Close the throttle barrel to the idle position.
Hold the carb to your ear. Yea, I know it looks silly, but it works.
While blowing into the end of the fuel tubing, slowly open the idle needle.
When you can JUST hear air blowing through the carb, the setting is within 1/8 turn either way of being right.
Now, start the engine and make your final low end and high end adjustments.

That might cure your problem.

Dr.1

RCVFR

My Feedback: (7)

I bought a new ST 40 a couple years ago, found it to be exactly as represented, breakin was by the book and uneventful. It was a user friendly, powerful engine with no bad habits or quirks. Maybe you should send yours in for warranty adjustment. This is definately not a finicky engine.

rainedave

My Feedback: (1)

What size prop are you using? I'd use a 10x6 for break-in as this puts a good, safe load on a forty. Also, make sure the engine is tightly secured in the test stand. Once I had a new engine that was loose in the stand and this caused the throttle arm to constantly move while the push rod stayed still. At first I thought the prop was slipping and causing the rpms to surge. So, also make sure the prop nut is tight.

David

Aviator 25

When I took the carb apart to check it over I found a loose screw, and a deformed needle valve seal (I replaced the needle). I also found a loose screw on the head of the engine. I ran the engine after and it ran a little better, but still not right. Last night I ran the engine and found fuel leaking from the fuel inlet fitting. Closer inspection revealed a crack in the inlet fitting. I replaced it and this improved the run, but still not enough to make it run right. Now the engine can be tuned in at high and when it's taken down to idle all is well, but as soon as you reopen the throttle the engine starts missing and surging until you retune it again at high. This happens every time the thorttle is opend, closed, and reopened again.

Sport_Pilot

If the engine was new, why did you take it apart? The warranty is there for a reason, now that you have replaced parts the warranty is no longer in effect. All manufactures have lemons, even OS, Rossi, Jet, etc.

Fastsky

now you know why experienced flyers buy OS or Thunder Tiger for their second, 3d, 4th engines.......

Hobbsy

My Feedback: (102)

Sky, you sure know how to help a guy. Just because you can't tune an engine don't take cheap shots at the rest of us who can.

rc34074

My Feedback: (5)

hobbsy - i totally agree with you regarding Fastsky.


Ed

Jezmo

Yes sir, I have owned at least ten and have yet to get a bad one including the ones made in China of which 4 are still in the family. Two G40's, a G51, and a new G90 that came into the family for Christmas. My nephew runs that one real hard and it never complains. Actually, the only engine I have owned that was bad was an old knockoff of the OS 40FSR made by Royal. It ran great but the metalurgy was poor and it just didn't last long. I kinda like the signature someone else on this forum uses - I never met an engine I didn't like.

Aviator,
Good luck with it. [8D]

NM2K

My Feedback: (14)

So, in a nutshell, we want folks to post problems they are having with their engines, but it isn't wise to slam a brand just because it has a problem. Why? Because all brands have problems from time to time. So lay off the bashing. Okay? <G>

But don't lay off of asking for help with problems. That is the reason for our existence.


Ed Cregger