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Engine basics => Four strokes only => Topic started by: Robin_Holden on April 22, 2014, 02:58:43 AM
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Greetings fellas from S.W.France.
I have a Saito 56 , the c/l version . I normally use a starter to fire it up.
Just found out my 12 volt battery has given up the ghost , won't hold a charge.
Advice please on a 'hand starting' procedure ?
Very much obliged ,
Robin.
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I always use a starter but some do hand start. If it's buried in a full fuselage airplane you can't get to intake to choke it. I sometimes put my finger over the muffler (Running muffler pressure) and turn it through a couple times to prime the engine but be prepaired to squirt fuel all over the airplane. Maybe someone that hand starts will tell us the tricks.
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Hello Robin and Bob,
I am far from knowlegeble in 4 stroke handling. I never even gave it a thought, just did my usual 2 stroke routine, choke the venturi, pull through several times until there feels to be plenty of fuel in the cylinder. Put on the glow current, turn over the engine and if it gives a bump, hit the prop. Usually starts first time. I occasionally do a back flip and that works too.
I have a home made choke on my 56 so that I can choke the engine, even if it is buried! I am sure the purists will shudder, but I have never even thought about a difference in starting technique between a 2 and a 4 stroke! I am sure there probably is, but my Saito doesn't seem to know.
Regards,
Andrew.
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I suggest you contact Bob Reeves ... he is on this forum.
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The few times I started my Saito 72 by hand on the test bench I found that the situation was always very clear; if I had choked it adequately it always started on the first flip, if I hadn't choked enough there wouldn't even be a pop and if I choked it too much it would backfire and start backwards.
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Saitos are a little touchy about prime. As said, if primed to little they won't start. If primed to much, they start backwards. I have a couple of old OS 4 strokes, and they like lots of prime and a back flip. They usually start the first time and like to be really wet. I have never used an electric starter on any engine. If they won't hand start there is usually something wrong although a starter on a 4 stroke is a good safety measure as they will bite if your procedure is wrong. Also when 4 strokes start backwards the exhaust becomes the intake and the carb is the exhaust. No problem unless you are using muffler pressure which will feed the exhaust and keep it running long enough to burn what ever is behind the carb. I never used muffler pressure on my OS engines, but I do most of the time on the Saitos as they seem to be a little shorter on suction. They will run just fine without pressure though. These are just the way it works for me, and there are many ways to skin the 4 stroke. So if your procedure works, use it.
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I've seen it done but I can't say I'd recommend starting a four-stroke by hand, especially the larger ones. Replacing your starter and/or battery is easier, less expensive, and much less painful than attempting to replace your digits. n1
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I used to start my Saito .56 by hand a while back.. it was fine with around 10% nitro, but when I switched to the Powermaster YS20/20 with 20% nitro, it would kick real hard at times when flipping forward. (especially in the cold) and have kill a few good wood props using a chicken stick.. not to mention my sore fingers prior. so bumping off the compression was the best way to go. but then it would run backwards at time.. and also its hard to get enough compression (when its hot) for back bump start from a back to back flight. So I use a starter.. problem solved. :) On priming wise I just put my finger over the exhaust.. (with muffler preasure).
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I used to start my Saito .56 by hand a while back.. it was fine with around 10% nitro, but when I switched to the Powermaster YS20/20 with 20% nitro, it would kick real hard at times when flipping forward. (especially in the cold) and have kill a few good wood props using a chicken stick.. not to mention my sore fingers prior. so bumping off the compression was the best way to go. but then it would run backwards at time.. and also its hard to get enough compression (when its hot) for back bump start from a back to back flight. So I use a starter.. problem solved. :) On priming wise I just put my finger over the exhaust.. (with muffler preasure).
What electric starter do you use ?
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Joe's method is exactly what I use on Saito 40 ....
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Yep, if you're running pressure just plug the muffler with a finger or thumb and then hit it with the starter. If everything is right it will fire up almost immediately.
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Good morning
I apologize for my bad English but i hope you understand the same.
With 4-stroke engines is really easy to suck up too much a mixture and cause starting backwards.
If this is your problem, you can inject a few drops of the mixture through the venturi and give a couple of shots to get her to the cylinder.
(It is easy if the engine has the cylinder down )
for departure to hand mounted the propeller so that placed horizontally shaft can do a little less than half a turn backwards before compression.
Take a flick backwards and propeller bounce by starting the engine in properly.
This system was described in the instructions attached to Saito in 2000 and has always worked for me.
The trick is just the right amount of mixture
Best wishes , Massimo
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The video at this address is better than all the words....
http://www.psaeroproducts.com/psaeroproducts/helpful_videos.html
Massimo.
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WARNING!!!!!!
Starting a 4-S engine by muffler priming works well BUT ----------------------------
If your pressure fitting at the tank is immersed in fuel and the engine starts backwards, it can continue to run, drawing fuel and air in through the muffler and exhausting through the carb. If this happens, things inside the engine compartment will get hot, VERY QUICKLY. Possibility of fire - definitely. I've seen it happen.
Bob z.