Saito 80 problems

r011ingthunder

Hi all,
I recently graduated from my first 5 litres of fuel to my second. The engine was running perfectly on the first lot but when I changed GH&M gave me a different fuel for the second lot (a higher nitro content?).

Anyway, the symptoms are as follws:
1. Harder to start and excess fuel pouring from the exhaust.
2. A banging noise from the engine when running, and a loud(ish) bang when I try to start it (electric starter)
3. The engine starting in a forwards direction then suddenly reversing and running backwards (I kid you not!!)
4. When it starts it ticks over "ok" at idle, but when I try to add a bit of throttle it dies or backfires and reverses rotation (as above).

I've checked the glow plug and it seems fine. I've checked and replaced (as a precaution) the fuel tank and lines. I've googled for the answer and it seems like the low speed needle might need adjustment, but this is not something I'm familiar with. I have tried adjusting the high speed needle but it made no difference.
The engine had been tuned to perfection by a friend who knew his stuff while it was running on the 1st bottle of fuel.
Any help much appreciated.
r011in

coolwings

Time to lean it out a bit, retuning for production of greater power. It's a bit rich for how much it has run-in so far. The Saito booklet is quite accurate in the description and instructions of what to do, but if you are still a tad vague on it, take a look at Norm-flyer's flying in Dublin website for detailed info on that.
All model aircraft engines can run forwards and backwards, but "sound lumpy" while running in reverse. It's no harm.
Actually some folks start them with a backwards flick, and if it starts forwards, ok, and if it starts backwards then throttle up and down 10% and it rights itself, smooths out, and revs up normally.
I start mine with a forwards flick, and usually it goes ok and about 10% of the time it will start in reverse, then I oscillate the throttle to make it right itself or cut out, then I can restart.
A rich setting makes it happen slightly more frequently, so the guys with extra powerful engines set rich will be more aware of this than budget engine users who have to lean their engine right out to get sufficient power.

Actually this happens to model car guys occasionally, even though their pullstart goes one way only, and it can cause broken recoil start cords They never know how it happened because their engine is declutched and nothing rotates backwards on the outside.

syl77

Hi r011ingthunder,
It may also sound like you have broken a part with in the engine itself, as this sounds similar to a problem I ran into with a saito 150. when you look at the engine you will see two bars which run from the valves down to prop turner. When opened, I found one of them broke, so it was firing only with one valve.. hense I got a banging noise, would quit on power up and also run in reverse alot more than usual.

You may not have same problem, So I would perform all other checks (lean as coolwings suggested) before you (or better yet some one that has a good knowledge with working with engines) carefully takeit appart to look for a broken part.

coolwings

Yes that's quite possible ... esp if it stopped with a bump recently, like in a mild bash, or a "hard landing".

r011ingthunder

Thanks lads, much appreciated, I'll follow "those lines of inquiry".
Cheers,
r011in

r011ingthunder

OK, I checked the conrods first as someone:mad: put the fear of god into me, but they were fine. I then went about leaning the idle needle. The reason I had no luck the last time was because I hadn't gone far enough. 2.5 full turns before she started to idle evenly!!! Anyway, by that time the shed was full of fumes (and I have a huge shed) and I had to get out! Next is to tune the main needle, which with the engine actually running should be a tad easier.
Thanks for the help, and yes the Saito handbook had good info on what I had to do, I just wasn't expecting so many turns to be necessary.
r011in

r011ingthunder

Ever start to worry when things go too right?? Since I tuned the engine I've been getting longer and longer flight times from it. I expected this, but not the amount I'm getting. I started by bringing her in at the 8 min mark to see how much fuel was left, more than two thirds of a tank!!! Then started to fly for 15 mins, and guess what? Just under half a tank left (approx). At this rate a full tank should last over 20 minutes!!! Anything I've read or heard about the Saito 80 has been not to expect much more than 15 minutes airborne.
I was worrying that she might be running a bit lean, so I started to enrich the mixture (high speed needle), and she immediately started running badly... oh I forgot to mention that she also runs very, very smoothly, I mean she sounds perfect.
Am I worrying over nothing? Should I just enjoy it while it lasts or should I investigate further?
r011in

coolwings

So you reckon no problems is a problem? :-)
The fuel economy comes from the engine being under very low load.
Enjoy it.

r011ingthunder

coolwings wrote: »

So you reckon no problems is a problem? :-)

Yes! Isn't that one of the fundamentals of Sod's Law? (I think Murphy's Law might be the technical name for that particular theorem).

coolwings wrote: »

The fuel economy comes from the engine being under very low load.
Enjoy it.

That's great news, thanks coolwings!
r011in