Frequently Asked Questions

This web site gets several thousand hits per month, and visitors occasional ask questions. This page lists some of the most frequently asked questions.

Q. Where do I send my engine for repairs, or to  buy spare parts ?

A.    USA
  Horizon Hobbies can help you. Since they are also the US importers, you can also purchase spare parts from them. Check their web site.
The web page with full parts lists is here.
 B.    EVERYWHERE ELSE            Good luck !

In the UK, the Saito importer and distributor is Macgregor Industries; you might try contacting them if you live in Europe.

Q.  I want to repair my engine myself and not send it to someone else for repair. How do I get the valve timing correct when I re-assemble the engine ?

A.  Why would you want to mess with your engine when there are competant repair services available? If you insist on trying your own repairs -- buy the Saito repair book that was formerly advertised in RCM magazine. It is a few years old and does not mention the most recent engines but should provide enough information for most repairs. However since RCM magazine is no longer in business I am not sure where you can now get this book.

Q.  What RPM should I get with my engine running a XXXX size prop ?

A.  I don’t know. It depends on the fuel, altitude, air temperature, humidity, prop size, prop brand, etc. After the engine is run-in a bit, measure the rpm with your prop and fuel and keep it for a reference. If I mentioned a value, and your engine measured say 100 rpm less, you would be unhappy for no good reason.

Q. Can I reverse the carb direction so that the needle valve is on the opposite side?

A. Yes

Q.  What is the difference between a Saito FA-56 and a Saito FA-56F ?

A.  The Saito-56F is a different version of the Saito-56 and appears to be sold in only a few countries; not the US. The letter ‘F’ means “Fun Fly”. The “F” version has a red colored prop drive hub. In the picture below, underneath the letter “F” on the red sticker on the box, it says “Fun Fly”.
The only mechanical difference I am aware of is that the carb throat diameter is smaller on the Saito-56F. This narrower carb inlet results in  better fuel draw, better fuel economy, and less power; why this is beneficial for a fun-fly type model is unclear to me.

Q.  My engine has two glow plugs in the head. Do I need to provide power to both plugs for starting?

A. No. Just power one plug for starting. The other plug will work by itself after the engine starts running.

My engine won’t start (or runs poorly, etc). I bought it from eBay and the seller said it was ‘Like New’.  What do I do ?

A. Don’t buy other peoples junk from eBay. If it is not new and never run, chances are there is a problem with the engine. For example: the crank-shaft might be slightly bent due to a crash, but may not be evident from casual inspection: the engine may have been run lean: or it may have rusted bearings, etc. If you are stuck with a problem engine, carefully check valve clearances, carb blockages, and bearings. Or just send it to a competant repair person.

Q. What does the small letter mean that is stamped on one lug of the engine?

A. The letter denotes the production run of a particular engine size.. The first run has the letter ‘A’, the second run letter ‘B’, the third run letter ‘C’, etc. A different letter does not necessarily imply a change or improvement. I do not know the dates that correspond to specific production runs; that would be a good exercise for a person working in a large hobby shop or distributor.

Q. What is the difference between the standard silver (S) metal engine and the black GK version.?

A.  The GK version is painted black. The internals are identical. Some of the GK versions have a velocity stack, and some do not. My Saito-56GK came without a velocity stack, and was purchased a few years ago.

Q. I want to install my engine inverted. The guys in my club say you need to install an on-board glow driver for inverted 4-stroke engines. Is this correct?

A. There is no need to use an on-board glow driver if the idle mixture is set correctly, you are using an appropriate brand glow-plug, and proper fuel. The idle speed will be reliable and just as low as for an upright engine.
Make sure the tank centerline is about level with the carb or a little lower; inverted engine problems are often related to the tank position being too high.

Q.  Where can I get a manual for my engine?

A. Try the Horizon Hobbies web site where you can download a manual. You may have to search around on the web site to find them. There are manuals for small singles, large singles, and multi-cylinder engines.

Q. My engine won’t run. If I prime it, it will run for a few seconds then quit. There is fuel in the line to the engine and the glow-plug is working.

A. Assuming there is no blockage in the carb it is most likely that the low-speed mixture is too lean. It is standard practice to start the engine with the throttle opened just above idle, or up to 1/4 throttle. At low throttle the high-speed mixture needle has almost no effect; the low-speed needle almost totally controls the fuel mixture seen by the engine. If the low-speed needle is turned in too far (too lean) the engine will start on a prime but not continue running. Try resetting the low-speed brass needle with its top flush with the housing as explained elsewhere on this web site. (Note: this applies to the two-needle carbs, not the air-bleed carb like on the Saito-30)

Q. My engine backfires (and sometimes loosens and throws off the prop) when I try to start it. However, once it is running the engine is fine.

A. The engine is too lean causing it to backfire. Do not adjust the carb needles to correct this. Carb mixtures should be optimized for engine running, not engine starting. Before trying to start the engine, prime it with lots of fuel. One way to do this is: disconnect glow-plug, advance throttle to full, spin over the engine with starter until fuel spray spits out exhaust, close throttle to 1/4 or less, connect power to glow-plus and start engine (with electric starter). If engine is inverted see extra note on other web page on ‘hydro-locking’. If the engine is inverted it is usually a good idea to pick up the model and tilt it sideways so that the exhaust port points down, turn over the prop by hand and you will see the excess fuel that was in the cylinder run out the exhaust, and there is still enough remaining fuel inside the engine for it to easily start.

Q. My uncle Harry is going on vacation to Japan. Can you tell me where he can get a cheap engine for me over there?

A. In the US the discount price for engines is about the same and usually a little less than the best discount hobby shops in Japan. I know where to buy discount and mail order RC stuff in Japan but I prefer to buy engines from  US stores as the price is a little lower, I get an English language instruction booklet, and I get a warranty and service if I need it. In Tokyo there are a couple of good hobby shops near the Akihabara train station. There are some nice small model kits sold in Japan that are not readily available elsewhere and maybe worth checking out, but don’t plan on getting an engine in Japan. Also, mail-order from Japan is usually not cost-effective as most places in Japan charge like wounded buffalo for shipping.

Q. My engine vibrates a lot, can I minimize this? The prop is balanced but I still get too much vibration.

A. All single cylinder engines naturally vibrate a fair amount, and some Saito engines will tend to vibrate a bit more than other Saito engines, due to size etc. The following will help without resorting to a soft mount. Carefully balance the prop using a good balancer like the Top-Flite Magnetic Balancer. If the engine is mounted on a flimsy model expect lots of vibration regardless of what you do; a solid mount and beefy rigid model helps. A metal mount will also help but does add weight compared to a plastic mount. After the engine is well run-in try resetting the two fuel mixtures on the carb. An overly rich low-speed needle mixture will cause more vibrations. Generally a new engine running fairly rich will vibrate much more than the same engine that is well run-in with correct fuel mixtures.

Q. I have stripped the thread in the head where the glowplug screws in. What can I do?

A. Be more careful next time; there is no need to remove a glow-plug unless it is not working and you need to replace it. Glowplugs last many years in 4-stroke engines that are properly run a little rich. Do not over-tighten or cross-thread the glow-plug. There are two solutions. First get a new head (expensive). Second, send the head or engine to Clarence Lee who can install a ‘heli-coil’ insert; the price is reasonable and he advertises in the classified ads of Model Airplane News magazine.

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