shleprock

I have a Saito FA100 that up until now has been flawless. I bought it new last Sept. and put about 5 flights on it after proper break in. After the winter break I have put about 1 gallon of fuel through it in a 4*60. After the 4*'s demise I installed it in a Pulse 60. I put 3 flights on the Pulse yesterday with no trouble. Then it started quitting at around 3/4 throttle after getting airborne. It seems to be fine at idle to 1/2 throttle. I checked the fuel lines and tank lines, installed a new fuel filter, and I removed both high and low speed needles and cleaned them. Now the engine runs great on the start stand. It transitions great, has a nice stable idle and runs up to full throttle great. It is still stalling when I get it airborne, though. The fuel is 15% cool power and a fairly new jug. I also put in a new glow-plug (Hanger 9 4-stroke super). The valves have not been adjusted yet as it's barely on it's second gallon of fuel. Any thoughts from the experts?

MetallicaJunkie

have you run it wide open holding it at a 45 degree angle.... you might want to check the tank for leaks, or the tubing for a puncture

shleprock

We ran it full throttle pointed up at a 45 degree angle yesterday before flying. It ran great for three flights, then the trouble started. I replaced the fuel lines in the tank and to the carb. I can't figure out why it runs great on the stand but not in the air. Very perplexing.

ChuckW

I helped a guy with an engine that always quit in the air and ended up finding the fuel stopper screw was stripped. The stopper didn't leak fuel but apparently it leaked pressure or sucked air.

I'd also take a look at the valve adjustment. Doesn't take much time so it's an easy thing to rule out.

Gray Beard

My Feedback: (-1)

I don't think it is the valves, it sounds like just a tune problem but I have found engines new, right out of the box with the valves out of adjustment. On a new engine I adjust the valves or check them after it's first gallon or so of fuel. It's worth a look and not a very hard thing to do.
I'm running into a problem that sort of sounds like what you are going through but with a two stroke and it craps out on me at about 1/4 of a tank draw down. In my case it is the tanks location, it is too far away from the engine and I loose pressure. I'm working on installing a pump right now. Just something else to look at in your search.

bingo field

I had a clunk in a tank I had to drill out, before the SuperTigre 90 would run up on the ground all right, but just shortly after take off and just after the turn, it would dead stick on me. Since I routed out the clunk, no issues. It would run all day on the ground.

shleprock

Thanks for the responses. I am still perplexed as to why I had three flights with out issues. Ran great without a stumble or hiccup. Ran great in the 4* before, too. I could try the clunk from the 4* tank just for the heck of it. I may just buy a new tank, it did seem very flexable near the stopper hole.

Stick 40

the valves may not be your problem, but I found that I needed to reset the valves on all my saitos twice, half way through break in and then after break in. Plus I always check them before even starting a new one ( or used ).

Are you useing a tech. I generaly tach. my saito's to 10K and they seem to run very well. If I tach. them to 10 K on the ground I should be under 11K in the air.

good luck

sticks

shleprock

I checked the valve lash and found both to be just a bit loose.

ChuckW

Loose is better than tight. Doubtful if that was your problem but at least it can be ruled out.

Gray Beard

My Feedback: (-1)

Trewer words were never spoken!!! I just had an exhaust valve rocker come loose, truth be known I think I forgot to tighten it after adjusting, my bad. It came all the way loose and allowed the push rod to work it's way under the lifter keeping the valve opened. No compression no run! First time I have ever done that but things do happen.
I never shoot for any special RPM, I use the tach to make sure I don't over rev the engine when I'm looking for the prop that will fly the plane the way I like it to fly but stay within the working RPM of the engine.
For tuning the engine I like the tach so I know when I hit the high RPM dead on then I can see when I get it backed off 3 to 500 RPM, most the time I can do it by ear but not always. My 100s aren't touchy at all and can run well even when they are too fat but don't run well when lean at all.

timcat26

If it will run up to 1/2 to 2/3 and then quit I'd check the exhaust manifold pressure lines as well as looking for any air leaks around the tank and stopper.

Andrewmc

I have had something similar happen on my Saito 56. The engine runs great in the pits, good idle and transition but when I accelerate for takeoff the engine quits.

Try going 1 click richer on the HS needle - 1 click only. Sometimes the needles are super sensitive - at least that has been my experience.

dignlivn

Try it a tad richer than what you have now.

Bob

Insanemoondoggie

Low end needle sounds like it,s to lean . Also , have you checked the glow plug ? It,s not uncommon to go thru a glow plug after a few flights on a new engine .

Jeff4318

Gary do you have any idea of where to posistion the prop on my new FA100 to get the best flip i plan to to use electric start eventualy but right now i cant seem to flip this eng. without choppin up my chickenstick

Jeff4318

Gary do you have any idea of where to posistion the prop on my new FA100 to get the best flip i plan to to use electric start eventualy but right now i cant seem to flip this eng. without choppin up my chickenstick

Gray Beard

My Feedback: (-1)

About one or two oclock at TDC for hand flipping. If using a starter I like to put the prop at three and nine oclock. That way if I get a dead stick the prop quit spinning and it's out of the way for landing. Sometimes my field has a lot of dirt clods that can break a prop, dead stick or engine running. Other then that 7 sq miles of flat is pretty nice. Oh and that auto axle busting hole once in a while can be a problem.

ec121

My Feedback: (2)

4 strokes do well with priming then a quick backward flip against the compression. When it backfires, it starts itself. I have seen people just spin the spinner backwards that way. You can also try running it without any pressure. It isn't really necessary. You just have to open the needles a little more for more flow. That would be a test to eliminate muffler pressure leaks as a problem.

richardgerardi

My 82 fa had about 20 flights and it needed valve adjustment.

Gray Beard

My Feedback: (-1)

I have found several brand new four strokes that required a valve adjustment right out of the box. I almost always check them on a new engine. Brand made no difference.

ec121

My Feedback: (2)

I agree. Never trust a new engine. Glow or gas. There are no "factory settings". Timing, needles, valves, etc. all need to be checked.

Gray Beard

My Feedback: (-1)

Don't you just love it when you get a new gasser that smells like gas when you open the box and it has the run up report someone filled out. Then you try to start it and it won't fire up. The needles are closed or so far out it won't even start. I have gotten a new one like that and the gasket on the carb was in backwards???
I check them all out as soon as I get them. The engines I get from Japan are almost always perfect but every once in a while!!!

benboy17

My Feedback: (34)

I have a 100 in a revolver that i had the exact same issue with. Turned out it was the clunk getting hung up when I would roll the plane. Check to make sure you didnt make your Clunk line in the tank to long when you replaced it. Mine flew fine at first then after about ten flights it started doing it. Once i fixed that never again have had an issue with about 50 flights on it. Hope this might help