freakingfast

My Feedback: (3)

YEAH! Take that, that'll learn ya!

Taz_Hobbies

My Feedback: (15)

Just not enough hours in the day to spend hunting down the issues. Easier to put the 1.10FZ on the Ult and put the bigger, heavier 1.20SF on the Funtana that won't balance!
Can I interest you in a super strong running OS 1.20AX? Run excellent, amazing vertical in the Ultimate, just doesn't run long! LOL.

blw

My Feedback: (3)

David, Taz...please finish the negotiations via PM to get around the selling in the forums rule.

Taz_Hobbies

My Feedback: (15)

Nobody advertised anything, it was in jest about an engine that doesn't quite cut it.
Forums, Moderators and Rules.... sheesh....

blw

My Feedback: (3)

I said 'please', didn't I?

Taz_Hobbies

My Feedback: (15)

Very True, you did.

Moderators....

RC_Fanatic

My Feedback: (1)

Just to drag this thread back on topic, I had a flameout with the 120AX in my Focus Sport (stock muffler). Oddly enough, it was flying straight and level, downwind, after a stall turn. Engine has about 40 flights on it and has not done this before. Checked everything over, no problems found. But, it would not start properly seemed to kick back and loosened the prop two or three times. (Another problem I've not had since I started flying this setup.) Finally got it to start and had an uneventful flight. When I got home, I noticed bearing noise when I rocked the prop back and forth. It was okay at the start of the day.

Coincidence?

Taz_Hobbies

My Feedback: (15)

Anything is possible. When you take the glow plug out of mine and run it thru slowly and gently, the bearings feel very, very smooth. Sure you can't tell the lateral movement of the rear bearing, but everything seems in order. I have run much more worn out pieces that had no issues.

The Supercharged YS 1.10 is in my Ultimate and will fly Sunday. The big OS is going on the test stand as a test mule until I can isolate the problem. I am starting to think hairline fracture in the liner or piston that only opens up at operating temp and compression will escape cooling the chamber causing the glow plug to snuff out. But who knows....

freakingfast

My Feedback: (3)

I'm just kidding ya! I'll never fault anyone for realizing life is too short for that aggravation. If it offends thee, pluck it out

Taz_Hobbies

My Feedback: (15)

Taz_Hobbies

My Feedback: (15)

Oh yes.... Starting to shape up nicely. Cowl cutouts are roughed in and the exhaust tubing mounted. Too bad the replacement cowl from Horizon showed damaged. Coincedentally so did the wing set I needed when the second Ultimate I bought showed up with damaged wings! Horizon needs to learn how to package fragile items a little better!

GRandolph

I have had the same flameout issues with my 95AX. I have changed the tank, taken apart the engine for inspection, and sent it off to Hobbico who found nothing wrong with it. I fly a plane with no cowl, spinning a 15x6 at 9300 rpm. It has good fuel flow and new tank. But despite everything being provided to this engine, it will dead stick after three minutes every flight. Stay away from these big AX engines.

Turk1

Hi, if you have problems with adjusting JBA 1.20 to proper run,let me know.Most probably you are in need to cure with carb.

Sport_Pilot

Bearing feel or even noise can fool you both ways. I have had bearings that felt notchy from congealed castor oil that were just fine when fuel was run through the engine for a while. I also have had bearings that felt perfect, but wined liked a police siren when the engine was running. The latter must have been from dirt as there was no corrosion but a groove wascut into the race.

gerryndennis

G'day Taz,

This could be a long shot but how long is the threaded part of the muffler pressure nipple?

A friend of mine had exactly the same symptoms, engine shutting done after around three minutes with the fuel line full. It turned out that the exhaust nipple was too short and was flush with the inside of the muffler, it was also positioned right next to the exhaust baffle. The pressure line was feeding oil from the muffler to the tank. Droplets of raw oil coalesced at the bottom of the tank and eventually got picked up by the clunk and were fed to the carburetor, resulting in engine shut down.

A longer nipple solved the problem.

Dave H

Fred L

My Feedback: (2)

i'm running a 91 asp in my 90 ult , had the same thing happen. would a fuel pump and tapping the back of the motor for it help?

Ernie Misner

Hi Fred, does it run okay on the ground or on the bench? If it quits doing aerobatics or when you hold the nose up or down a pump might be the ticket.

Keep us posted,

Ernie Misner

jaka

Hi!
The reason Taz and others have problem with their engines is that they use aftermarket Pit style mufflers with too large out let holes and too little volume!
All OS engines (and all others too) run perfectly good as long as you treat them right and follow some simple rules.

1. Always mount the engine and tank according to the "tank mounting rule"!
2. See to that you have enough cooling if you mount the engine inside a cowl. Just taking up holes is not enough!!! You have to stear the incomming air around the cylinder tightly.
3. Use the standard silencer first and set the engine right so you see that everything works ok. Then you can try it out with a aftermarket silencer.
If it doesn't work out ok you know that it's the aftermarket silencer and not the engine.
4. No modern engine needs 10 hours running in time. Just a few tank is all it takes to have a perfect running engine.
5. use 5-10% nitro fuel! 15% is a waist of money!
6. Use an OS 8 or Enya 3-4 glow plug! No OS F plug is needed!
7. Use the right size of tank! In Taz case a 16oz tank is ok.
8. Use the correct size prop, in Taz case a 14x8,15x6 or 16x6.
9. And most important! Set the engine a little on the rich side to compensate for loss of pressure as the fuel level drops during flight.

RC_Fanatic

My Feedback: (1)

I think you were referring to my post about the noisy bearing. As it turned out, the rear bearing was bad and the engine runs well now that it has been replaced. Glow plug had some microscopic bits of material stuck to the coil.

Fred L

My Feedback: (2)

it ran great on the bench and on the ground.....more then likely a carb problem as the engine is old. I was wondering if anyone knew weither a carb from an ASP 108 would fit a 91. they are like $15 on Hobby King

Ernie Misner

If the 1.08 carb has a larger ventui, you would be even more likely to need a pump. Why not stick with the stock size carb.

Ernie

Fred L

My Feedback: (2)

like i said, it's an old engine, kinda hard to find parts for it. i'm a bit lazy too, i'd rather pay $15 for a new carb then take the old one apart and try to find parts. where can i find a carb for a 91ASP? I didn't even think they made those engines any more. Probly do like Taz and get a good 4-stroke for it , either that or stuff a tater in one of the down tubes of the pits muffler on it ( i like that idea ).

Ernie Misner

Hi Fred, even if you do get the 4-stroke for it, you might keep your eyes open for an old carb off of any .91, OS or whatever for that engine. They usually all have the same mounting specs. I had a SuperTigre 90 (same mount size here too) that ran great with a carb from an old Tower 75 engine. Good luck.

Ernie Misner

Fred L

My Feedback: (2)

LOL Now ya tell me that! i just put both my Tower Hobbies .75 2 strokes on ebay. Just my luck. I just went to Hobby King and noticed they still have a .91 ASP for cheap.....just a long wait.

Ernie Misner

Like a girlfriend, you'll find all kinds of carbs when you least expect it.