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Saito FG-30 gas troubles

Old 08-09-2010, 03:27 AM
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Gabrielsande
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Default Saito FG-30 gas troubles



Hi there!,
I have a saito FG 30,I had it from new, is being bench tested tunned and runned in,using 20-1 amsoil dominator oil

http://www.youtube.com/watch?v=r4kaiM2vhYc

it started very easy,no ptoblems at all, setted high end for max rpm then opened a bit ,the low end needle for a smooth idle and quick pickup,all was looking good!.

Then I fitted the engine to a Goldwings 30cc 73" MX2 very light and nice plane, had to cut the firewal back and reinfroce it because the engine is quite long, so after this got all ready, took off and no trim needed at all, very smooth fast and accurate to fly,didn't want to abuse the engine so just tryed to hover and was doing it at 1/2 stick and pulling out vertical very fast, pleased with the whole setup.

So here is the problem, noticed on take off was hesitating on full throttle when speeding up (the patch Ifly is very short) and loosing a bit of power for a split second then ok, also when flying straight and going very quick to a nife edge (on the left side) the same hesitating and losing power a bit then ok.

Didn't bother me because I knew the engine still new,but know having a good 20 flights, last weekend spent lots of time trying to sort this out with no succes, ovious thing to do is get the low end richer Idid also the high end. still doing the same, only getting rougher running, and it was misfiring a bit on the middle stick at level fly, Itried all the possible neddles combinations, same resault , that hesitation
allways there,sparkplug is new,checked no much carbon just a nice mushrom grey colour.

Had a dubro Easy fill valve Ioverrided just in case,changed the fuel lines for bigger ones ,and I done the plumbing dead straigth from the tank to the carb,going just trough a filter,tank is close anyway. (also changed the clunk and clunk line)

Im a car mechanic and im being playing with engines since my 13s, so my ears are well used to a well tunned engine!,

so my guess is, Ibelive this engine has a walbro type carb,but with a barrel like the glow ones, also Ithink they dont use a diaphragm pump system due the lack of back pressure being a 4st, so my guess is they are using an ocsillating one, which it might not work properly at high g forces manouvers, the actual ballbearing inside might just stop or slowtoo muchfor asplit of second when the airplane rotates too fast in the same direction, drooping the fuel pressure a bit.

If you fly normally, just scale aerobatics is just fine,but if you put the sticks in the corners, it will do it then is ok,when going quick to knife edge it does but then goes ok you can do figure 8 knife edge circuits through the whole tank! is just the very quick change of direction which affects the engine.


So my other plane is a 63"sukhoi with a cheap crrc pro 2st 26cc, a bit less power ,but once riched the sweet spot never gave me a trouble,dont miss a single beat using just a chanisaw walbro carb!,so If this saito is more suitable for scale, war bird aircrafts, I might sell it and buy a JC28cc or dle 30cc for less money, SAito sounds awsome! but is much heavy 400g more up front ,wings rocks a lot and is hard to keep a harrier stright and ifI cant sort this problem will be betteron ascale plane instead!!

Any ideas

Thanks!!


Luis

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Old 08-09-2010, 10:08 AM
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Default RE: Saito FG-30 gas troubles

The engine is better suited to a scale or general sport plane and is generally not suited well for 3D for it is too heavy for the power output.

The pump in the Walbro has a return spring. The carb gets its impulse for the pump from the intake manifold vacuum itself and then has a spring return. There is also a regulator on the side of the carb.
Old 08-09-2010, 10:30 AM
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Gabrielsande
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Default RE: Saito FG-30 gas troubles

Hi there! thanks for the information!

Apart for that issue, the power to weight ratio is more than adecuate,this frame as you see in the pictures is very very light,prop hangat 1/2 throttle and goes up like rocket from there, also loops on knife edge,so what you think could be wrong?,I fitted this engine to a showtime 90 before and again it was a plessure to fly,same thing very powerfull,but it was doing the same thing, on a different tank,plumbing,dif frame!.

mmm, Im think will take the carb apart and have a good look just in case,something is sticking, could be the oil Im using?? this amsoil dominator oil states you can use as low as 50:1, Im on 20:1 as the saito manual for UK.

anyway thanks very much!
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Old 08-09-2010, 11:32 AM
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Default RE: Saito FG-30 gas troubles

When you use a synthetic oil like amsoil dominator at such ratios as 20:1 there is a hard carbon formed that gets around the the rings and on the valve stems

It is better that you use something else!
Old 08-09-2010, 04:16 PM
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Default RE: Saito FG-30 gas troubles

Hi again!

Going through the manual, Ijust noticed, saito recommends a 6v battery pack for the ignition, at the momennt, Im using a 2s-2200 lipo with a regulator,but it was set for 4.8v!
so this could be the problem the ignition quitting at high load, so moved the jumper switch to 6v, will try this wednesday.

about the oil extracted this from the manual:


Mix a ratio of gasoline to oil of 20:1for break-in and continuous operation on all engines. <o></o>

A mixture of high-quality 91 octane unleaded gasoline and a reliable high-quality 100% synthetic oil for 2-cycle engines must be used (we recommend Evolution Oil, EVOX1001Q). <o></o>

Note: With the use of an oil mixture of 20:1, it is normal to see a slight amount of carbon buildup on the exhaust valve itself. <o></o>

This is why it is so very important that you use a high quality synthetic oil and not just the standard 2-stroke oil you may be currently used to using in your 2-stroke gas engine. We have found that although these 2-stroke oils work well in their intended applications they can cause a build up of a gummy type residue on the exhaust valve in a 4-stroke gas engine and this potentially leads to the need for sending your engine in for service as the exhaust valve begins to stick and not seal properly. <o></o>

The high quality Evolution oil we recommend using will still build up a slight amount of carbon, but we have found that this build up is easily flaked off during normal operation of the engine and will not create the aforementioned typical gummy build up.


Thats wy Im trying this amsoil dominator oil,fully synthetic little carbon build up etc etc.

http://www.performanceoilsltd.co.uk/...acing_oil.html

Being this good probably should use it at 30-35:1 ratio instead 20

Old 08-09-2010, 05:35 PM
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Default RE: Saito FG-30 gas troubles

Also, fitted to the saito fg-30 gas a smoke sytem using a perry pump, it works but smoke is not too thick, fitted the injector to the blaked, hole on the stock silencer, Ibelive is just the 180 glow one with the backpressure niple blanked off, shall I do an other hole on the actual manifold close to the cylinder head?to fit the injector??, and which fuel tube should I use, tygon one is melting down!!.

Temporally Ifitted a very short piece of glowfuel tube (silicone)next to the exhaust, which Igave a bath on water with sugar and coke,to protect it from the diesel fuel Im using for smoke. which tube will tolerate diesel and high temps???


Many thanks!!
Old 08-09-2010, 06:38 PM
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Default RE: Saito FG-30 gas troubles

But the oil residue on the valve stem when you use Amsoil Dominator at 20:1 is like a steel coating and extremely hard and will cause the exhaust valve to stick. This hard carbon also forms around both sides of the ring. It is almost impossible to get off. (Will require disassembly of the engine)

Use of an oil intended to be used at a ratio closer to 20:1 and the carbon formation on the valve stem is softer.

If you use Pennzoil aircooled mineral oil at 20:1 the smut on the valve stem will wipe off the valve stem with a Q-tip through the exhaust port. The ring area will be clean.

The Evolution oil they recommend is Morgan's Synthetic Kart oil that has been repackaged for Horizon. It would be better than using the Amsoil.
Old 08-10-2010, 01:20 AM
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Default RE: Saito FG-30 gas troubles

Brilliant! will order some evolution oil then

Thank you!
Old 08-10-2010, 03:34 AM
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Default RE: Saito FG-30 gas troubles

Don't know why saito didn't fit  needle bearings on the rod,to alllow using bit less of oil, these engines shares the lubrication of a 2 stroke kind of hibrid at the end
Old 08-10-2010, 07:25 AM
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Default RE: Saito FG-30 gas troubles

There wasn't room for needle bearings on the rod without a complete redesign of the engine crankcase. They tried to use as much of the original glow design as they could.

It was a compromise
Old 08-11-2010, 05:05 PM
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Default RE: Saito FG-30 gas troubles

Right, after,reviewing, the plumbing again,and switching the regulator to 6V, checked the carb settings, all ok running like a clock, nice idle and quick response from idle to full power, set the high end for top rpm then backed up a bit, as usual.

So on takeoff ,no hesitation at all, and flying was perfect, not a sigle miss, quick rolls were nice not loss of power there, landed all good, Iwas so happy having this puzzle solved, so had a brake and A chat with my club mates,re-fueled and up again, this time the gremlins came back,same thing same fault when changing direction, eaven the engine quitted completly, luckly managed to land safelly, with just a small 1/2 inch rip on one of the wings covering.

I have a fly logbook, just to keep on eye on my engines,repairs.time in the air, etc,so going through it I added just less than 2hs (+45mins bench time)running time on this saito!, and this fault was from day 1.

To be honest,Im losing my confidence and patience with it, dont like the barreltype carb,the actual barrel is plastic!,anyway Iknow is a good piece of ingeneering and sounds great,but I think if Ihave to service this carb in future,will be just with original spares,going throug saitos channels, the rest of normal 2 st engines, uses just standard walbro carbs, easy to set up, easy to find spares, very simple!. my CRRC pro 26i was 1/4 of the saito price,it looks and sounds horriblebut is being a year now, just starting it ,flying it,and cleaning it. not a single problem apart from some factory issues at first (mostly for buying it from ebay ) they are sold in uk now with warranty.

Im just gonna put away this plane for some time and fly my others,but Ithink will sell the saito which still like new and buy a dle30 or cj28 evo.

will see........


thanks for the info !
Old 08-12-2010, 04:48 AM
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Default RE: Saito FG-30 gas troubles

Interesting, some of the smaller 100 and 125 Saito glow have a problem with factory bearings going out, sometimes in short order. The symptoms I have experienced sound similar. I wonder if you could find out about the bearings used in the gas version?
Old 08-13-2010, 02:05 PM
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Default RE: Saito FG-30 gas troubles

Hi there, coming back to this problem, could be the engine getting a bit hot?, because the very first flight is ok, and if you fly gentle is ok
Old 08-13-2010, 03:53 PM
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Default RE: Saito FG-30 gas troubles

Yes
Old 08-14-2010, 04:44 AM
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Default RE: Saito FG-30 gas troubles



Yes? hey,thanks for your support, and input, im sure will sort this problem out

Old 08-14-2010, 08:56 AM
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Default RE: Saito FG-30 gas troubles

The Saito gas engines in cowled airplanes need more cooling than the glow engines do.
Old 08-14-2010, 05:37 PM
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Default RE: Saito FG-30 gas troubles



what's the normal temperature on these? Next time will give it a go without the cowl,and if better then will open the bottom of the cowl a bit more, also blank the front scoops up

Old 08-14-2010, 05:58 PM
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Default RE: Saito FG-30 gas troubles

I believe you need to keep it under 149 degrees C max (300 degrees F).
Old 08-15-2010, 06:08 PM
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Default RE: Saito FG-30 gas troubles

Thanks,for the info,

done few mods today,found couple of problems,first the carb was touching the firewall,and the manifold bit lose,so carved a square on the firewal about 4mm deep to clear it,didn't want a complete hole to avoid messing the inside,put some locktite on the carb mount bolts, also the ignition module was strapped to the engine box on the side (inside of the engine bay),so just in case of temperature problems, managed to move it inside of the fus nearly were the cg is,so will be cool and also will help the cg,moved the tank back too, the plane was a bit nose heavy so all this will help.

Opened up the cowl a bit on the front, now you can see the whole cilinder and cylinder head from the front,and the same at the bottom near the exhaust,cutted a big hole there,and the front top sccops blanked up to avoid excess of air coming in and making an airlock,just drilled few holes to allow some air going in to the engine mount and crankase.

Also found the throttle rod binding on the firewall hole,so made it bigger, carb barrel can move out,there is no guide,so if it was moving because the rod touching a side,could lead to alter the mixture, (onthe manual says you can pull the barrel from the throtle arm to allow more fuel to prime the engine).

Lets see, will give a try this monday afternoon,done a temp test in my garden without pushing it too much and headtemp hovers around 86C, will check after landing tomorrow.

Cheers!

Little video of it in the air,the engine sounds great,thats wy should do the impossible to keep it!.
http://www.youtube.com/watch?v=lFu0UYwkdy4
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Old 08-15-2010, 07:34 PM
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Default RE: Saito FG-30 gas troubles

Lets hope that the ignition box being close to the CG will not place it near any of the radio equipment so as to cause RFI into your reciever and creat a crash?
Old 08-16-2010, 02:39 AM
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Default RE: Saito FG-30 gas troubles



Ignition still far from the reciever which is a 2.4ghz, i just managed to get it out of the engine bay,which after each fly was very hot.
theribs had a shape to installa fibreglass channel which comes with the kitgoes from the front to the back, in case of using a canister type exhaust, so ignition is right under the tank deck,but isolated of the engine bay,and a bit towards to the cg,the ignition battery was also next to the tank,moved back too

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Old 08-16-2010, 07:58 AM
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Default RE: Saito FG-30 gas troubles

Sounds good
Old 08-18-2010, 05:01 PM
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Default RE: Saito FG-30 gas troubles

Right tested it today

After all that time spent on sunday STILL THE SAME!!!,took off, and was doing the same losing power on knife edge,missing at half throttle,etc etc!.

so Took the cowl off and done few adjustments to the high end and low end,before trying again with no cowl, and then!... I looked to the ignition sensor and I thought mmm lets try to move the timming,so released those bolts enough to let me slide the sensor,then fired the engine up, and it was mising at half throttle,like being reach, so left it at half throttle, and moved the sensor foward and backwards and the problem disapeared!!, it was too advanced from factory!.(i know it migh be because different fuels,but my other cheap chinese engines came tested and set from factory,never had to move the timming at all!)

 Then set the high end for max rpm and backed up a bit,same to the low end, lean to a nice idle then back a bit, took of with no hestiation, knife edge was perfect eaven wanted to loop on the rudder on low rates,very consistant fly  pretty fast just at 1/4 throttle,hovers at 1/2 and pulls out super fast!,

 but if you fly too slow and let the engine cooling down, when you go quick to full throttle from there and you pull up sharply, it coffs a bit and then goes,good because does not lose power it keeps going,flying at level is ok from idle to full power, is just when pulling up sharply. same as with a glow engine. this fault really does not bother me, but I think it could be cured just fine tunning those neddles betwen flights.

Still waiting for the evolution oil, still with the amsoil dominator for now,but at 30=1 instead the breather pipe lefts a nice oily trial on the bottom of the fus,anyway Im not pushing the engine too much,full throttle just for short periods and only going up.

 

Will post an other video soon

Old 08-18-2010, 05:05 PM
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Default RE: Saito FG-30 gas troubles

Be careful running the 30:1.

The problem will show up at the rod if there is one?

You might can feel this at the prop after it starts to go?
Old 09-19-2010, 05:02 PM
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Default RE: Saito FG-30 gas troubles

Hi there, just and update.

After few weeks, mixed some fresh fuel at 20=1 with the recommended evolution oil, started it I let it warm up, and It was running very smooth and great, picking speed up very quick no problems.

So applyed full gas, and then the same, almost died on take off, in the air the same problem again, and when going up just died. so got it back made the high end reacher ,and again the same. in the ground is ok but flying still doing the same fault, it is much better with the timming retarded, at least it runs smooth through the whole throttle, but a sudden change of direction on the flying will trigger this, like a lack of fuel pressure, dont know what more to do, apart of cleaning it and sticking it on ebay!.

took the carb apart and all looks ok, dont know if worth to adjust the fuel diaphragm needle height,gaskets looks ok not dry they are the stock black ones, for my other walbros you can get the fuel oneway valve gasket in a kind of blue fibre more rigid than the rubber black one.will increase the little arm height a bit to make the diaphragm lifting the neddle with less pressure, to increase the fuel flow, it might help dont know any more!!

Sent an email to mcgregor uk to see what they say,but Im not to optimistic, nearly £500 of an engine wrong from day one,I own few petrol engines, and never had a problem like this, I know some people upgrade the carb gaskets,some upgrade the ignition for a rexcel one,spark plugs,etc so way spending this much on an engine to then change everything,better of buying other brand from start! (and they are 1/2 price)

Ayway still sound good and will be a shame to let it go,let see what they say.but this will be the last try!!

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