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Saito 325 radial running problem

Old 04-18-2009, 04:14 PM
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Ghostrider FIN
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Default Saito 325 radial running problem

Hi all!

I have onboard glow with Saito 325, when plugs are powered engine runs good i think. (21x8 Menz propeller gives 6300rpm) instanly when plugs are unpowered engine quits one cylinder. and after switch on glow again it fires and continues with 5 jugs.[sm=spinnyeyes.gif] What may cause this bad fuel, bad plug, where i should start to recovery?

-I mentioned that needle haft to be open 5 turns. Actually i can screw needle off from carb and engine runs still about 10 seconds. Until starts to loose rpms.

-I have Saito´s plugs on rear and front on jug. Does hotter plug on front help anything, like OS F on back and OS A3 on front?

-Fuel are 10% nitro, 20% Klotz Techniplate and 70% methanol

-Every jugs has good compression and it is measured same to all jugs.
Old 04-18-2009, 05:23 PM
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w8ye
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Default RE: Saito 325 radial running problem

It is a mixture distribution problem
Old 04-18-2009, 05:49 PM
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Default RE: Saito 325 radial running problem

I have been tried many times, but if i turn main needle to leaner engine starts to loose rpm. I know that usually single cylinder engine are way too rich if it stops or drop rpm´s when glow is disconnected. Plug can be bad also.

Which are basic needle setting what should be ok so i can test those new settings[sm=confused.gif]
Old 04-18-2009, 10:27 PM
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Default RE: Saito 325 radial running problem

Use 4 stroke plugs in all spots and run a gallon of fuel through it. Make sure there are no intake leaks and the valves are adjusted.
Old 04-19-2009, 08:29 AM
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Default RE: Saito 325 radial running problem

Ok thanks. I need to test run engine again. Yesterday i changed new OS F plugs. I check out those valve clearances and adjust them if necessary. Thanks for help
Old 04-19-2009, 12:02 PM
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Default RE: Saito 325 radial running problem

Btw. How to detect intake leaks if any? Intake pipe nuts seem to be tightly on diffusor housing. And other end of pipe is fitted with O-ring to cylinder.
Old 01-05-2012, 12:58 AM
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kiwibandit
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Default RE: Saito 325 radial running problem

Hey Ghostrider.
I have one of these engines fitted to an ESM La-7. The hi speed needle setting you speak of (5 Turns out) will be too rich for un-powered plugs. The setting on mine is only 2 - 3 turns depending on the weather.

I can assume that it is one of the lower cyls that is quitting on you. Have you used large dia fuel tubing? These engines drink fuel at an alarming rate, 75cc per min. Also - is the tank getting enough exhaust pressure.

I have my tank level with the carb and it runs fine with no exhaust boost to the tank at all.
My experience with this engine has shown that the length of the exhaust pipes play a significant part in the smooth running. Short pipes will give erratic idle. It will sound cooooollll. Very much like a rotary with a neat loaping sound. Long pipes will improve the idle greatly.

Check out these two links. They are of my setup.

http://www.youtube.com/watch?v=SC0DaCQAKiE

http://www.youtube.com/watch?v=XCo_U...eature=related

Good luck,
Trev.
Old 01-05-2012, 04:47 AM
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Default RE: Saito 325 radial running problem

GR, when the HS needle is ineffective it usually means that the LS needle is too lean. The cure is to richen the LS needle richer than ideal, then peak the HS at absolute peak, then set the LS needle. Now, set HS needle for whatever your tank set up will require. The too needles effect each other somewhat but since the HS needle has a fixed seat you eliminate one variable by peaking it temporarily.
Old 01-05-2012, 04:24 PM
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Default RE: Saito 325 radial running problem

+1.You can also reduce the oil content which is what i did on my r3 200 radial.Now run 12% syn and 3% castor.
Old 01-06-2012, 11:45 PM
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Default RE: Saito 325 radial running problem

My 325 has hot and cold cylinders but they will drop out only when the L/S needle is much too lean or too rich. Try to identify the extreme cylinders by watching exhaust residue. The cold ones will pas a lot of oil and the hot ones will make very little residue by comparison. Search for intake leaks on the hot cylinders. I would drop the oil content to no more than 15% and work with the carb assuming every cylinder has equal valve lash and compression.
Old 01-07-2012, 01:42 PM
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Default RE: Saito 325 radial running problem

One thing worth mentioning here is that on a single you will notice a lean condition because the engine will either stop or kick the prop off. On a multi cylinder engine the rich enough to run cylinders will keep the engine going and the odd lean cylinder will quit because the combustion is too short in duration to heat the plug suffeciently in that cylinder. Think of the lean cylinder as if you were trying to heat your house with Kleenex in the furnace, the fire wouold be fast a furious but make little to no heat.

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