beginner/pro

I am new to the world of RC planes yes.. but have been flying sims some 25 yrs.. I bought into this hobby and keep buying old barn finds.. have some really neat birds. Anyway I have this .91 four stroke I am having difficulty starting and a .90 size two stroke I have yet to get fired.
The four stroke Ihave flown about three times, each a dead stick landing.. but now I can't get it to fire. The last time I was able to get it running and trying to tune it I had it idling beautifully and shut it off to put the wing on(yeah Iknow, should have had it on first..) and then it would not restart.. then when I finally could get it fired it would only barely idle.. and die immediately when Itried anything., that was two attempts ago. Ican no longer even get it to fire.
The Two stroke I can't get to fire at all either. I have to cowboy up and take the cowl off so I can do some more involved trying, as I can't even cover the intake or exhaust to prime it, and my starter doesn't seem to be able to hook up enuf to spin it so I'm left with a chicken stick... I need to enlist a helper to hold the bird, but she's fragile and I'm nervous.

Ok, go ahead and post when you're done lyao

rcflyingnut

My Feedback: (9)

You say barn finds. Have you gone through the planes and checked everything? This could be caused by several different things.

Try changing the glow plugs and make sure your glow driver is charged and working. I personally like the OS glow plugs, especailly for the four strokes. How are the fuel lines coming from the tank to the motor? Are they new or old? They could have holes in it allowing air into the line. This goes for the fuel line and vent line. The lines could look good, but it only takes one little hole to cause problems. Is the stopper in the fuel tank sealing properly? I would start there and see what happens. If you check those things and still does not run; you might need to clean the carbs and make sure you don't have trash in the needles.

Campgems

Find a local club and someone to help you. Your planes are doing you a favor by not starting. Flying a simulator and flying a plane are not the same thing. Chances are about 99% that your plane will not survive the first flight. A club can hook you up on a buddy box and let you get the feel of the plane. They will also help you with the setup of the planes. No simulator Iknow will do that.

On the engines. The manuals will have a starting point for the needle valve and idle mix control. You didn't say what engines you have, so it will be hard to give you a hint on what the original settings should be.

With both the high speed and idle set to the manuals recommended setting, the engines should start and run. The settings for one are most likely different for the other, so you should treat them as individuals. You didn't say if these are new engines or second hand engines that are broken in. Big difference on how you will treat them for a while.

Lets assume that they are in good condition and broken in. With the carb set to the initial setting, start the engine and let it warm up at 1/4 throttle or less for a minute or so. Then go to full throttle. As you are a newbie, you should use a tach to set the engines. Adjust the high speed needle for maximum RPM, turn it lean an eighth turn and hold for a few seconds, then adjust again. When you find the peak, then go to the rich side by around 400 rpm drop. If you get 350 that's good 450 is also good. Now set the throttle to idle speed,as slow as you can and keep the engine running. Very slowly lean the idle mix, 1/16th turn at a time and again wait, You will do this until youget the maximum rpm without changing the throttle. Now go backand do the high speed over again. Back to the idle and this time the engine should idle slower. Your goal is a strong idle at 2200.Again adjust for max RPMat a fixed throttle set toidle. Now work on the transition. The engine should jump from idle when youhammer the throttle. If it sputters and coughs and slowly gains rpm, you need to lean the idle mix a little more. If it dies as soon as you punch it, it is to lean, open itup a little and then try again. The carb tuning is a balancing act. You can get a carbtuned for max RPM, but it will not idle at all, or you can get it to idle but not run at any throttle above idle. To know where you are, you need to start the adjustment procedure from the factory setting. Again theyare different engine to engine and manufacture to manufacture.

It is a good idea to tune and make a few flights without a cowl over the engine. You can see what is going on and the needles are easier to reach. Once you haveit running right, say five or six fights without any issue, then you can put the cowl back on and you will most likely have to tweak the settings to make up for the different air flow.

One thing is bothering me. You stated that you couldn't get to either the carb or muffler to put your finger over it to choke the engine. You are in for a lot of problems if theexhaust is clear of thecowl. Your engine will not run well as it will be trying to suck in exhaust fumesVs freshair. Also the plane is going to be a mess inside with all that oil beingdumped in. The exhausthas to dump outside the plane.

Back to my first comment, find a club and getsome hands on help. You will make a new friend andyou will likely go home at theend of the day with a smile and not a bunch of crunched balsa.

Don

TedMo

I agree check or replace all fuel lines. Best way to eliminate problems is to put engine back on bench, get it running and tuned then into plane.

FILE IFR

+1

You'll be better off in the long run by getting experienced help tuning/ starting.... and even flying. You'll learn a great deal.

scooterinvegas

My Feedback: (1)

Planes that have been sitting awhile most likely have oily gunk in the tank. Take the tank out and replace it, their CHEAP. New tanks come with a new stopper, witch you need. New fuel lines with a filter between the tank and mixture screw would be next.

Take the back cover off the engine and make sure it is clean and no gunk or rust. Open the mixture screw and blow out the carb to make sure it is not plugged up.

After you do these steps, report back your finding. Scoot

beginner/pro

Thanks for the reply, Iguess I didn't give enuf info.. sorry. I bought a friends hobby about 15? mos agoafter pining for it for 20+ years.. There was a .28 high wing trainer, a 91 4str. cub, and a really old 60 2str Bipe all rtf, plus a low wing arfthat needed some repair.. I started studying, cleaning, learning, fixing.. I bet I have read every page I could find on the net and bought the sim.. Ihave a pilot buddy who also bought into it and threw me a control and threw his hz super cub in the air and my first flight I was flying inverted in that 3 channel like you wouldn't believe. Thenperformed a dead stick 3 point landing in thesnow on skis.Which hehad yet to do.. or since. I know I sound like a punk but I was blessed what can I say. Ialso am a talented musician and an accomplished off road motorcyclist.And like I said, I really have been flying sims since they were publicly avail.
So anywayI bought one of those super cubs and flew it about a dozen times and then moved to a pz ultra micro p51 which yeah I crashed a couple times, but soon found out it was not my flying but a sticky servo. Still.. the tiny bird in the wind sucked and I wanted to fly a big bird! So I summoned the courage to take the big yellow goldberg cub w/the four stroke out and get her fired.. ran thru all the cheks.. oh yeah, I failed to mention, that months before that I had taken the trainer gas plane out and failed to perform a test of the DIRECTION of rudder and well you can imagine how short that flight was..
Anyway I got the big cub together and tested and took her to the soccer field and had the most fun 5 minutes of flying in my life. This was my first 4 channel real flight and I of course had to do rolls and loops and try my best walking, flat spinning, goin crazyand what not.. oh yeah windy all days it seems.... then out goes the motor.
I was movin okand had some altitude so I brought it around some and down not 20-25 ft away from me. Then immediately acted like the biggest geek the world has seen who just got it w/a su!permodel after winning the lottery.
Well thenI had todo that again.. but not that day. Went back another day andhad a similar experience,then refueled andcould not stay running, then no re-fire...thats whentroubles began.
Itookher home,frustrated and upset. Another day, testing,another day similar flight storyas #2.... then I'm pissed. I gogetmy FAVORITE bird.. the one thatgot me into it.. The bigorange biper that I just loved. Did my best at tuning.. seemed touchy butgot her goin and up inthe air and man was I tickled.. nervous.. got her trimmed out though and started having fun, doing tricks and all andthen on a biglong dive shedies... and I try to scrub speed but had not had any experience or even heard of slippingyet... andwhoosh..she goes rightby me! I have to make a lastsecond 90 degree left and set her down about15-20 ft later!! PHEW!!!!!!Needlessto say Idrain,after run, pack her up and go home sassified!
Now I have left out tons of stories about failed attempts which I like to call learning experiences, but they all have been in getting the bird to be flight ready, not piloting. Still, my big gas birds are unscathed. And I have picked up a way too nice I should not fly it one-off F6F Hellcat I am chomping at the bit to fly. This ice snow and subfreezing temps are killing me! I am wanting to make some nice skis. Just needing some time, and knowledge.. learning.

Thanks All