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saito 125a fs

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john melia 113/04/2017 15:39:30
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i've just bought a saito 125a fs ,and installed it in a seagull glasair , the tank came with the model , and has a built in mount in the fusalage where i have duly installed it

the engine is mounted horizontal as per the manual , but the fuel supply from the tank is approx 2 1/2 inches below the carb

i have not got any experience of fourstroke glows , only two strokes glows , and petrol engines

would this cause a problem , if so is there any type of pump i could use , and where could i get one

Phil 913/04/2017 16:29:45
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first of all john the saito 125 is a very nice engine

for general information about saito this website is very good.

ideally the centre line of the tank should be level with the carb or a little lower. but I would just try it as see if it runs ok it might work out fine, if not a perry pump or Cline regulator would help

Jon - Laser Engines13/04/2017 16:44:07
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Lower is better than higher but a quick look at the manual does confuse me a touch as there seems to be no reason why its not mounted higher up. I would see if you can raise it up to the square cut out in the firewall, or see if the location is better with the engine inverted. Clearly the latter is only an option if the cowl has not bee cut yet

..13/04/2017 17:51:19
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As above John it should run fine like that. One thing to have in mind with the Saito is that they rely on the low end needle for around 70% of operation so tuning one is slightly different than othe two and four stroke engines (not any harder just different).

The 125 is a fantastic motor , very powerful and extremely light too, love mine.

john melia 113/04/2017 19:00:39
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When i put my finger over the carb or exhaust , the fuel is drawn up into the carb , but it drains back down the pipe again , it doesn't stay there
Jon - Laser Engines13/04/2017 19:02:42
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while not a good sign its the running performance that matters. If you aren't happy then move the tank> it might be a hassle but its only wood, time for the old cut and stick

cymaz13/04/2017 19:14:55
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Posted by john melia 1 on 13/04/2017 19:00:39:
When i put my finger over the carb or exhaust , the fuel is drawn up into the carb , but it drains back down the pipe again , it doesn't stay there

Would a one way check valve help that?

john melia 113/04/2017 19:50:01
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Cheers cymaz , I've just ordered that , can't do no harm
..14/04/2017 07:54:28
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Have you actually run it up in the airframe yet John ? I would defiantly do that before trying to cure faults that may not be there.

john melia 114/04/2017 09:03:56
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It's already in the model Justin as per opening post
john melia 114/04/2017 10:06:27
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i knew i should of stuck with petrol and bought a two stroke face 19

Phil 914/04/2017 10:19:02
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Posted by john melia 1 on 14/04/2017 10:06:27:

i knew i should of stuck with petrol and bought a two stroke face 19

oh please no.

the noise from these horrible motors is horrendous to the point that I hate a busy club day. I used to love a good turn out.

plus without testing it you don't yet know if you do have a problem

Denis Watkins14/04/2017 10:25:17
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Woe John, It is very common to have a tank height discrepancy, and it is much better to have this lower than high, as syphoning from a high tank is a nuisance causing hydraulic locks.

Your four stroke will have no problem lifting that fuel; it is a quiet motor too and will give great progressive throttling to the Glasair

You have the best of everything on your bench right now, and will have great flights

..14/04/2017 10:28:41
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Posted by john melia 1 on 14/04/2017 09:03:56:
It's already in the model Justin as per opening post

Yes I realise that John but from your post I was unsure if you had tried to run it or not ? Will it not fire at all then ?

john melia 115/04/2017 10:58:23
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Had it running for a full tank , takes some starting by hand though
Could i put a 16x8 prop on the saito , only reason i ask is it's the only prop i have available, i did have a master screw 16x6 but it kicked back when starting onto my stick and took a chunk out of the blade
Martin Harris15/04/2017 11:13:34
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Why not use that tendency to kick to your (and your prop's) advantage by adopting the reverse flick method?

cymaz15/04/2017 11:15:25
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What does the manual say? 16x6 maybe??

Phil 915/04/2017 11:18:55
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Posted by john melia 1 on 15/04/2017 10:58:23:
Had it running for a full tank , takes some starting by hand though
Could i put a 16x8 prop on the saito , only reason i ask is it's the only prop i have available, i did have a master screw 16x6 but it kicked back when starting onto my stick and took a chunk out of the blade

with the tank lower you may find it more difficult to draw fuel into the carb to get it running but once started it should be fine.

a 15x8 is a good prop for this engine a 16x8 is a bit to much I think and if it is a fairly new engine I would defiantly not use it. I always preferred an electric starter as the kick back can be strong

Denis Watkins15/04/2017 12:00:22
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You probably know that the 16 x 8 is top end with this motor John, and the motor may even turn it OK when run in, but right now this will overprop the motor and not help run in.

The guys have suggested the best start size and to use an electric starter as there is only one ignition to every 2 revolutions, your hand flick barely gets it up to speed, but after the run in is complete, a hand flick may do it

Edited By Denis Watkins on 15/04/2017 12:01:13

john melia 115/04/2017 12:08:05
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Thanks guys the motor is already run in , by the guy i bought it off
Compression is very strong , and as you say that kick back is severe , i cant use a starter at present as i don't have a spinner , tried reversing the rubber insert on my starter to fit on the prop nut but it just chewed it up

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