Hi, I have an airboat that has a saito fa-50 engine on it. I'm having trouble getting it to start and run in cold weather. Can anyone help me? I have the high speed needle 4 turns out and the low speed needle flush with the throttle lever. It is an older engine and I want to get it to last a long time. Thanks!

I've never had one, but isn't that a 4 stroke? Could the valves be too tight in the cold weather? try heating it up with a hairdryer before starting it.

Ya, it is a 4 stroke. Thanks!

4 turns out seems like a lot. The standard for most engines is 2 turns. If it is too rich, it will not run hot enough and will die. Does it even run with the glow plug warmer on it? Does it want to start? Is it getting fuel? Is the glow plug glowing? If it runs then dies when the glow plug warmer is taken off, it is likely too rich. Need a lot more info to help.

The saito website says that 4 turns out is ok. It wants to start. I can get it to start, but then it dies, I also think it is two rich, I've tried to lean it, but it wouldn't start after that. It runs with the glow warmer off.

can you advance it to full throttle? If not, try it with the glow driver on. Tune the high end first. You'll need to do this using a tach, then richen it up until your RPM drops by about 200 rpm. Then slowly lower your throttle to idle. If it surges after you hit idle, the low speed mixture is too lean; if the RPMs slowly drop after hitting idle, the mixture screw is too rich.

Make sure you're not over proping it and running good fuel as well, or else you'll never be able to tune it.

You may also check to make sure you are using a 4 stroke glow plug. I always use an O.S. Type F. They are not cheap but I've had them run for years. You should also check your fuel system. If you are priming the carburator the engine will run till it burns up the prime fuel then it will die. You could have an air leak or a restriction somewhere in the fuel system( check the carb needles too.). A Saito engine is a high quality engine so you should be able to get it running great unless this engine is old and worn out or it needs the valves adjusted. Good Luck! Dennis

ok, thanks.

One thing I just noticed is that fuel shoots out of the carborator. I'm wondering if that is the problem. Can anybody tell me how to fix that?
I've never messed with the timing so I'm not sure.

It's a side effect, not the problem. If fuel is shooting out of the carb, it is too rich and probably flooded from trying to start. When this happens, it becomes hard to start because the glow plug gets drenched. If you never messed with the cam, your timing should be fine, but you may want to check the clearance on the valves. Does fuel come out when it is running or when you are trying to start it?

It would be helpful if you could provide a detailed description of what you're using in your setup (glow plug, fuel, prop, outside temp) as well as a detailed step by step of what is happening to the engine. Stuff like: what happens when you start it, does it die immediately, does it die when advancing throttle, does it doe when the glow plug is off, what RPMs are you achieving, etc...

Steve

Sorry, I should have earlier. Anyway, it is cold out. Maybe 30-35 degrees. I use a master airscrew 10X7 3 bladed prop with a great planes 4 stroke glow plug.I use Omega 15% 4 stroke fuel ( that was all I could find on the bottle). I attach a fully charged glow plug heater to the glow plug. I prime the motor and attemp to start it. It fires and wants to start. Fuel shoots out of the carborator. Eventually, it starts, still shooting out fuel. I detach the glow plug heater and it still runs. Later, it dies, and I can't get it to restart. Can anyone help me?

thanks! Tuning in cold is really tough, partially because your hands freeze with the prop blast. I've been tuning engines for over 20 years and it definetly sounds like your running it way too rich and it is having a hard time keeping the glow plug warm enough. Some of my engines have a hard time restarting when they die, never figured out why but it is usually because they are flooded. Are you familiar with tuning 4 cycle engines? Once you get it started, attempt to advance to full throttle. If it is spitting out fuel or the RPM isn't increasing as you advance it, lean it out. Keep the glow plug warmer on it if you need to get it to full throttle. Once you hit wide open throttle, keep leaning the high speed needle valve until you hit max RPM. Then richen it up a couple clicks. Then lower the throttle to idle and see what happens. If the RPMs wind down and it dies, lean the low speed needle valve. My high speed needle valves are all 1.5-2 turns out. If the RPMs surge up, richen the low speed needle valve. Either way, be sure you tune high end first. You may also need to set your idle high because the cold weather. Let me know how this works for you or how far you get in the attempt. Good luck.

Ok, thanks. I just got a tachometer as a Christmas gift. I have not been able to get it running long enough to be able to read it so I'll try it. Thinks again!