Ding Hao

My Feedback: (2)

I have a recurring problem with my Super Tigre 90, running on 10% glow fuel. First of all it powers an eindecker looking aircraft with a half cowl and is mounted with the cylinder head down at about eight o'clock looking at the front of the engine. The problem is it leans out and shuts off in about 5 minutes. I noticed the needles valve was loose where it was threaded, so I bought a used engine and replaced the whole carb over the winter. I ran it on a test bench for 10 minutes and it ran solid at all speed ranges. I put it back in the bird and I was deadstick again in five minutes. I have cleaned and inspected this motor for cracks and find it flawless. When I put in a new #7 O.S. glow plug it seems to help, but I still have unexpected shutdowns. I have been campaigning this plane for three years and know my tank is positioned right. I would appreciate any help on this subject and if any one knows where I can get new parts for engine , let me know, when she runs it has a lot of power, but I am running out of runway. A.J.

mrbigg

My Feedback: (21)

Just curious as to how much fuel has been put through the engine. I know you said you've had the plane three years, but not sure if this engine is new to the airframe. My .90 when new had the same problem. After close to a gallon of fuel it went away. Even running it rich wouldn't help. It would run all day on the ground and die in the air. I'm running an osf plug with 0% fuel and its a nice running engine. No complaints now.

the pope

Hi I know this may not help but my 90 has been flawless but mine is upright . Have you thoroughly checked out the tank , lines , position etc . Air leaks are their biggest problem in my opinion . Good luck from the pope

1QwkSport2.5r

My older ST S90K really needed 2+gallons of fuel burned in it before it was throttling really well. I think this is 75% of people's troubles with ST engines. The other part is getting the needle set right. Dead sticking after 5 minutes means the high side is lean. What I found I had to do with my S90K was to set the needle with a pinch instead of the usual 2-3 clicks rich. Once I started using the pinch method, it started to behave and not stall/dead stick on me. My engine ended up needing to be 500-600rpm rich of peak to not get hot and quit. A Frank Bowman piston ring will expedite the break-in process significantly and would have had my engine behaving better much sooner. ST rings take forever to bed in and all the while needing a rich midrange and burbly transitions to run well enough to not quit on you. Just my thoughts, perhaps it needs more runtime.

Ding Hao

My Feedback: (2)

My troubled ST90 has been flying this plane over 2 seasons and was used when I got it. We started running it rich enough to leave a smoke trail and it seemed to run good, except for the flame outs last summer. AJ

Cyberwolf

My Feedback: (4)

What muffler and prop are you using on the 90 and which model ST 90 is it?

Ding Hao

My Feedback: (2)

The motor says Super Tigre ,made in Italy with what looks like a G surrounding the 90. I am using a stock muffler the swings down under the landing gear. AJ

aspeed

Just a thought, is the fuel pickup pushed forward from a hard landing? That, and a hole in the pick up tubing would do this.

Dago Racer13

if it runs fine outside the plane then its something in the tank. Run it on the stand in the same 8 o'clock position
and see if it runs fine. If it runs fine on stand in 8 o'clock position then pitch the tank and the lines and start
fresh. You must have an air-leak somewhere in the fuel tank set-up. Don't forget the foam around the tank too.

1QwkSport2.5r

My ST S90K gets revved up a bit (tuned muffler) which makes it vibrate a good bit more... I advocate well balanced props (blades AND hub) and bubbleless tanks for them. No chance for bubbles then. Jett, and Tettra are two that come to mind. I have a Tettra 14oz that works well with the .90 and my 1.20 4-stroke.

Dago Racer13

I race Club40 and I use to race a lot of quickies, and Jett & Tettra bubbleless were the way to go. I have over a dozen Super Tigers and don't normally have problems with them.
The tank is the most important part of the whole set-up. The race planes rev anywhere from 16,500-17,200. Foam, balancing, and the bubbleless are why I never had a deadstick
in the last 5 years. Bubbleless are a little pricey and not everyone gets how to pump the fuel in, but a regular tank thats not leaking air or fuel will do just fine on any sport plane.

Cyberwolf

My Feedback: (4)

I also agree with the tank or fuel tubing being your issue, but here is another item to check. Since your using the stock muffler make sure that it is not pushed in to far on the outlet tube as that can cut back exhaust flow and cause issues in itself. Also with the G series 90 that engine is not an RPM maker like the S&K Series was, prop it for around 11.5 and it will stay happy.

Ding Hao

My Feedback: (2)

Gentlemen, Thanks for all your help, used your wisdom and flew my ST90 for 2 eight minute flights today. Now I am cranked up for a show at the end of the month. Thanks, Again, AJ