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Saito 120 Trouble

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Saito 120 Trouble

Old 08-20-2008, 08:35 AM
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Daz167
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Default Saito 120 Trouble

Hi everyone,

I used to use this Saito 120 in my Topflite GE P47, I have now re-homed it in a ESM Hurricane. Ever since swapping it out I have had nothing but trouble with it. It just keeps stopping. I have even moved the position of the fuel tank so it is spot on in line with the Carb. Still no luck! The only things I have changed on the engine since swapping it over is I have changed original muffler with a Saito flexible exhaust and onboard glow. The onboard glow seems to be working fine, but I am a little concerned about that exhaust. On the exhaust there is no nipple for the fuel tube to attach to from tank....so I was told to just hang the fuel tube outside the cowling and that would work fine. Is this correct or do I need to install a nipple on the exhaust to allow back pressure?

Please, any help will be greatly appreciated......this plane has sat in the garage way to long!!!!

Regards
Daz
Old 08-20-2008, 09:21 AM
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Edwin
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Default RE: Saito 120 Trouble

I have 4 saito 120s. Not a hotrod but a very good engine. Any time I change a component or move it to a different plane I retune the carb. How many hours on the engine, hows the maintenance been, what kind of fuel. I run 2-stroke 10% with 18%synth/castor oil on all my four strokes (saito/OS). About every 40 hours or so of run time I'll tear the engine down and remove any carbon buildup. I forgot one year and had pretty bad idle problems before doing the clean up, work fine after that. My oldest 120 has pretty close to 200 hrs on it.
Edwin
Old 08-20-2008, 11:20 AM
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Gray Beard
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Default RE: Saito 120 Trouble

Fuel tube?? Is that the pressure line you are talking about??? Just wondering???
Old 08-20-2008, 10:38 PM
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Daz167
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Default RE: Saito 120 Trouble

Hi Edwin & Greybeard,

Thanks for your prompt responses! Edwin, in regards to fuel I use 10% 2 stroke fuel....not sure on castor content....I'll have to check. I think I might take engine off plane and put it on a test bench, I'll also clean the carb as you suggested. The engine is only a baby and had around 12 flights....basically still running in I suppose. I swapped this engine from the P47 because I didn't have the money at the time to purchase another saito. I put a 91FX into the p47, which performs beautifully!

Greybeard in response to your question, yes it is the pressure line, sorry.

Regards
Daz
Old 08-21-2008, 09:21 PM
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rc-sport
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Default RE: Saito 120 Trouble

You need a pressure nipple on the exhaust. My 120 is the most reliable engine I have, it's in it's second plane and didn't require any retuning. I run Wildcat 15%-18% oil and when I reallly want performance I run 30%.
Old 08-22-2008, 02:03 PM
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Default RE: Saito 120 Trouble

I agree with 'RC-Sport' you NEED back pressure to keep the fuel flowing!

I have a Saito 120 FS also and I could not get it to turn up to full speed even with the back pressure... so I increased the size of my fuel lines and added a 'PERRY PUMP' to ensure good fuel delivery - I gained 1000 rpm on the top end and have a totally reliable idle at 2000 rpm.

Good Luck.
Old 08-25-2008, 07:14 AM
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Daz167
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Default RE: Saito 120 Trouble

Thankyou to everyone who has responded...your solutions are greatly appreciated. This is the only four stroke I own and they are a lot more touchy than a two stroke for setting up. (Still...you can't beat the sound a four stroke makes )

I took the carb apart last night and gave it a good clean...but it was already relatively clean. Then I started to look at the exhaust and I'm now considering putting on the original exhaust just to see how if it will run. Like I said earlier I used to run this engine fine with the original exhaust system. I will leave the engine in the plane and do some more tests on the fuel lines to check everything is ok.

I've attached a pic of the P47 which was the orginal home of the Saito 120. The P47 now has an OS91FX, which flies it nice.

Regards
Daz
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Old 08-30-2008, 06:30 AM
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Daz167
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Default RE: Saito 120 Trouble

Hi again...

Well this weekend I changed over the exhaust to the standard exhaust from the flexable exhaust. Moved everything back to stock positions (low idle to flush with throttle linkage housing) and the main needle to 4 turns. Started first go! Then I set the main needle to slightly on the rich side, then proceeded to set low idle which was quite easy to achieve (I only wish I had a tacho to get the settings perfect!) I think I'll buy one just to make sure I have the rpms just right. I got my wife to hold the transmitter while I put the plane vertical to check it would hold Idle as well as full noise.....great! I'll take her for a run on Sunday.....but first I'll give the old girl (plane) a bit of a clean, after all she was sitting in the garage for about 4 months!!!!!

So in my appreciation, thankyou to all you guys out there for your comments and time.

Best regards
Daz

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