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Starting a Saito FA 56b How?

Started by RWalton65, December 13, 2015, 20:57:26 pm

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RWalton65

Guys,
I've got a new Saito FA 56b and am trying to start it on the bench to run it in. The first session it wouldn't even pop or wheeze. This is despite doing everything by the book. The following day I tried just a little drop of fuel in through the glow plug hole and it fired up and run for two 8oz tanks full. Nice and rich and at ΒΌ throttle. Now I can't get it to start at all.
These are the settings and methods:
Close the fast idle needle fully then wind it out 31/2 turns.
Open the throttle fully, put finger over end of exhaust muffler and hand turn three of four turns until a small drip of fuel comes out of the carb.
Apply the glow starter.
Wait 10-15 secs then crank the prop using a chicken stick.
I'm doing everything as per the destructions and not so much as a pop or bang. The fuel is coming up the line and the tank centre is at the same level as the car body. The glow starter is fully powered up and when I remove the plug and insert it into the starter it glows a nice bright yellowy orange.
Should I get an electric starter and just crank it or are there any suggestions you can give.
I thought I might be flooding it so I took the plug out and cranked it over a few times, left it to vaporise etc. then tried again with lower needle settings. I even went on the Saito home page and followed the instructions to the tee. Nothing! Help?

PDR

Difficult to advise without feeling the engine, but a few random thoughts:

You may find it won't hand-start that well until the ring is bedded, and until that time it will respond better to an electric start. This isn't uncommon.

You may find that (like many 4-strokes) it hand-starts better by bouncing it backwards against compression rather than pushing it forwards over compression.

I've not heard of a running-in procedure that involves extended running at 1/4 throttle - my feeling is that the engine wouldn't get hot enough to bed the ring properly (and may suffer acid condensation in the oil, so make sure you give it a flush-out and dose of after-run oil to avoid crankshaft & bearing corrosion). I would do the initial bench running at full throttle and slightly rich. A couple of 2-3 minute runs should be enough; then just fly it a little rich for the first few tankfuls. Running a gallon through on the bench was only for lapped-piston engines in the 1960s!

PDR
There are no shortcuts on the long, hard road to success. But if your dad's rich there could a limo service...

British Victory

Saitos when new are lubed up with some molyslip type oil/grease. It's black anyway. They recommend a procedure that keeps the engine sloppy rich and gradually work toward a leaned out setting.
My advice is to not wait 15 secs after applying the glow start but just before applying it turn the prop by hand over 3 or 4 turns to ensure there's no hydraulic lock then apply the glostart and start it up. My saitos need to be quite "wet" to get going and they do start pdq by hand but they don't take prisoners so be careful.
An electric starter is a good investment and can save much frustration
there's only one f in RCMF,
               John

RWalton65

Thanks for the responses guys; that's very much appreciated.

It sounds like I'm not getting enough fuel into the piston from what you're saying. At the moment I'm using a "chicken stick" as I'm not confident of putting my fingers in the way of it. I'll get crimbles out of the way and invest in an electric starter, or maybe get one of those rubber cups and mount it to my de Walt screwdriver gun. That has masses of torque and turns at 2000rpm. That should save carrying the big battery around and it'll always be on hand.

Thanks again.

.....

Quote from: RWalton65 on December 13, 2015, 20:57:26 pm

Open the throttle fully, put finger over end of exhaust muffler and hand turn three of four turns until a small drip of fuel comes out of the carb.
Apply the glow starter.
Wait 10-15 secs then crank the prop using a chicken stick.



Are you trying to start it at full (wide open) throttle? It's not generally recommended!
Does sound like you're under priming a bit and also note that at this time of year engines which will flick start readily can be extremely grumpy as the fuel doesn't evaporate as readily and this can make it harder to start than on a nice warm summer's day (remember them  $%&) .

RWalton65

Quote from: Spider Pig on December 14, 2015, 09:53:04 am
Are you trying to start it at full (wide open) throttle? It's not generally recommended!
Does sound like you're under priming a bit and also note that at this time of year engines which will flick start readily can be extremely grumpy as the fuel doesn't evaporate as readily and this can make it harder to start than on a nice warm summer's day (remember them  $%&) .


A warm summers day!? Jeeze! I'll never get it started!  :'(

No not at full throttle. Reading the Saito website it says to open the throttle fully and put your finger over the end of the muffler and crank the engine by hand  to prime the piston. Fuel may drip out of the muffler but that's fine. Then close the throttle to about 1/4 open then apply glow starter and turn by electronic starter. The Saito instructions with the engine talk about cranking it by hand forcibly with the glow starter attached and you'll feel a distinct "Pop" when the engines primed! Yeah right!! I'm really going to do that!

Based on the replies received so far I think it's a case of the cold weather making vaporising the fuel harder, not enough spin on the engine to draw the fuel through the carb and into the piston, thus not enough fuel coming through.

I think I'll hold off trying to run the engine until it's warmer. I've got the time as I'm only about 20% through building the model.

Thanks again guys for the advice. Much obliged.  ;)

.....

Sounds like a plan.
Though a devotee of glow power, I decided a while back that kneeling in the damp doggedly trying to flick start a grumpy glow engine in the depths of winter is a mugs game, so it's electric finger in the winter for me.
It's not that you can't flick start in the winter, just that it's generally more sensitive to priming than it would be in the summer.

Windy

December 14, 2015, 16:18:30 pm #7 Last Edit: December 14, 2015, 16:22:55 pm by Windy
Quote from: RWalton65 on December 14, 2015, 12:42:24 pm
...
Reading the Saito website it says to open the throttle fully and put your finger over the end of the muffler and crank the engine by hand  to prime the piston. Fuel may drip out of the muffler but that's fine. Then close the throttle to about 1/4 open then apply glow starter and turn by electronic starter. The Saito instructions with the engine talk about cranking it by hand forcibly with the glow starter attached and you'll feel a distinct "Pop" when the engines primed! Yeah right!! I'm really going to do that!

Based on the replies received so far I think it's a case of the cold weather making vaporising the fuel harder, not enough spin on the engine to draw the fuel through the carb and into the piston, thus not enough fuel coming through.


With fully-open throttle (glow plug not connected of course!) and a finger completely closing the air intake the motor should draw up fuel into the carb easily when you move the prop over slowly. That should get the combustion chamber wet**, possibly to the extent that you need to rotate the prop anti-clockwise to let excess fuel out through the valves. When the motor can be turned over reduce the throttle to a gnat's above tickover (or guess this with a new engine) without locking, clip on the glow battery and spin or flick the prop.

Cold weather can affect a puny glowstart cell. A better solution is a 2v lead-acid cell (eg Cyclon) with the glow clip on the other end of a metre of servo cable to drop the voltage a bit.

Having seen what a mean-minded 4-stroke can do to a screwdriver handle I'd never start such an engine by finger. But holding the prop securely while slowly turning past TDC just produces a "bump".

Or go electric, but keep your LiPo's warm.

** Unless you have mounted the motor with its carb below the inlet valve of course. Side mounting can make starting easier.



alanh

I have found Saitos difficult to hand start due to high compression ratio .I always start 4 strokes with a starter even small ones . Electric starters can cause bent con rods on small 2 strokes due to hyraulic lock .This is not a problem with a 4 stroke . My start procedure is simply apply a glow start then wind the engine with the starter .I have done this for 20 odd years and never damaged an engine . Another thing is use an OS F type plug they are expensive but last years and perform well and will take 2 volts from a lead acid battery .
Alan
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