hi,
bought an asp .91 and have been trying to get it to run, when i do, the engine sounds like its running backwards and has no throdle response. can anyone give me the correct needle settings for the high and low end needle? any other tips? im useing 10% nitro and a 13x8 prop.
thanks,
lee

Take the carb off and look back up through it. If it is the kind with a cat eye slit in the bottom of the spray bar, you will need to screw the idle screw in or out so that it extends half way accross the cat eye when the throttle is wide open. If in doubt, err on being out too far rather than in too far.

If you have the spray bar type that the bar only goes half way accross the venturi and you can see the idle needle coming from the idle side, The idle needle should be about 1/16" away from the end of the spraybar when the throttle is wide open. If in doubt, err towards being a little farther apart.

The High speed should be started about 1- 1/2 turns out.

They tend to run backwards when the crankcase gets flooded. They will have no throttle response when running backwards except they usually quit if you open the throttle up.

This time of year, you may need to run a hot plug?

13-8 or 14-6 is about right.

Good luck,

Jim

thanks for your response, it is getting chilly here in md. What type of fuel and plug do you run in yours?
thanks,lee

i use 10% Omega and a Tower Power Plug.

how would you compare the asp .91 to the super tiger and os ~.90's?
thanks,
lee

I consider my Super Tiger 90's to be much more robust than my ASP 108. They turn a 14-6 at 11,200 at 60 degrees. I had a 15-8 on my ASP 108 and it would turn 8,800. I cannot remember what the S T's did with the 15-8 but it was somewhere slightly above 9000 if I remember.

There was a OS 90 at the field and I thought it did alright. It had a 14-6 on it and sounded good but don't know what it was turning. He destroyed the plane and went on to someting else for now.

I think the new Magnum XLS 91 to be a very good engine.

Magnum, ASP, SY, & SC are all the same thing made by the South Aero Engine company in Hunon, China.

jim

Jim,
i have set up the carb the way you told me to and still all i can get is 5-30 seconds of running and then it abruptly shuts off, any suggestions?
thanks,
lee

Just last week I was running a Super Tiger 90 and after running most of a tank of fuel it shut off suddenly. From then on, that's all it would do is run a short bit and shut off. I tried new plugs and the whole bit.

I removed the motor and took it all apart, and found nothing wrong. I changed the carb from a ASP 90 carb to a Suprt tiger carb and put it back in and started it up but it ran exactly the same. I finally changed from a idle bar plug to the Tower Power plug which is a close cousin to the OS #3 and it all ran like nothing had ever been wrong.

This may not be the problem with your's but it sure helped mine. I did notice that the engine ran a lot faster with the ASP carb than the Super Tiger carb. The ASP carb is bigger.

You might also try leaving the heat on the plug until you get the engine up and running and get it hot?


Good luck,

Jim

Well , I know it's been 6 months for me and I still have not got either of mine to run yet .

I have searched these pages for ideas and have have tried each and every one . All in all I have not solved the problem either.

Have got Identical Problem, Can't seem to get any more power after 1/2 throttle. Have opened low sp. needle which allows me to open throttle to almost full power but to get it to run , HS needle is so open there is no power to get it off , plus all the fuel is running out the muffler.

Have had quite a few members at my club to help and it's been the same way for everyone , (both the >61 & .75 ) I also have the .108 NIB and am afraid to try.

The Carburators are identical , on all of mine , Don't remember on the .108 .
I have the .40 size that I run on a profile airplane and have no problems.

Someone suggested take the carb off and try a Supertigre carb.
Hate to spend anything on these . But Could it be the carbs? I switched them and still have same problem.

Low end seems like it HAS to be opened at least 5 turns out from close . ( throttle at closed position ) and the high seems like it wants to be at least 4-5 turns out from close .

Can't seem to bring it in any closer , where the engine will even start.

Let me know what you ended up doing to solve .
Thanks ,
Tony

I have three of the carbs. One for my ASP 108 and two ASP 90 carbs that I use on my Super Tiger 90's and the high speed needle runs around one turn on each one. The super Tiger carbs are the same way.

Jim

fly guy it's been a while since your post, are you still having troubles?

I just finished tuning my SC .60 today, it ran like hell for a while, untill i found the low speed needle (thought it didn't have one at first ) and kept cranking it in, almost 4 turns. the high end is 1 & 1/4 out. sounds like you're flooding the hell out of your engine. especially since raw fuel is coming out of the muffler.

put the high end at 1 1/2, and put the idle screw in one turn to start with, start it up and get a fast idle, advance the throttle semi-slowly, and if she coughs and sputters the idle is still too rich. put the idle screw in 1/4 turn and start her up again, repeat untill you get a smooth transition from idle to full throttle. if the idle is too rich it's hard for the engine to accelerate.

for the high end, take it to full throttle for about a minute then drop it to idle, if it runs on for a while like an 85 escort, then drops down to idle, it's too rich, if it stalls it's too lean. get a good spot then out 1/4 turn so you don't lean out when vertical.

I just learned this from one of the older guys at the club, then burnt a 1/2 gallon getting it right, just educated trial and error. the engine will run great once you get her tuned. there's another thread here about adjusting the spraybar on a supertigre .91, might be worth a look since they might be the same carb.

.

alo I would add,.............. 5% nitro, and no green fuel. Also when it starts at idle, a pinch test will tell you the same as it does anywhere in the throttle setting. My 91 ran great for three years, then started loosing power on the top end in flight. I rebuilt the carb, added the factory reccomended and supplied head shims, and the problem was still there. Put my os 61 carb on it, never a problem since. 7d carb.
d

My ASP .91 has a habit of running backwards if a bit overchoked. Something about the rich mixture. Sometimes blipping the throttle will make it run foward. Usually you have to stop it by pinching the fuel line, usually it starts righ up after that.