Fresh fuel, battery charged, rotated prop several times prior to starting to start. Prop and motor turn over easily but can't get to fire. Pulled spark plugs and they were clean but "damp" with fuel. Tried again with same results. Took out plugs again, same look. Attempted three (3) times and stopped trying for fear of some type of gear damage. Did not have this problem a few months ago but plane has been hangared and only cranked once in that time. Probably need to clean carburetor and put in fresh batteries, possibly floats. Any suggestion would be greatly appreciated. Many thanks!
Slip of the finger. Meant battery. Spoke to gentleman I bought it from since post he said sequence is turn on fuel pump and check for any pressure drop, forward on enriched valve, main switch on, clear prop then start with throttle forward and enriched valve off. After two tries he said battery would be drained and would have to charge and wait. Sound about right? Let me know.
No, not a bit. They are all different, MiniMaxes. Most of them are set up to start with a primer plunger or a squeeze bulb to pressurise the fuel into the float bowl Others have a choke. Sounds like you have an electric pump although most 447s have a pulse pump. It is recommended that a fuel pressure gauge is fitted. The spark is provided by a magneto (of sorts,) and there are two types. One uses points and the other a CDI system which is easier to live with. Most start from a pull cord and a few are fitted with starter motors.
Generally speaking, if the engine will turn over at more than 300 RPM, the ignition provides enough energy to make sparks.
First thing to do is remove the sparking plugs and fit two new ones into the caps which are not then screwed into the heads. Turn the magneto switch on (up) and either engage the starter or pull the cord. Observe the sparks. No sparks, electrics at fault.
Sparks, over priming or too much choke. (Most likely; they don't like being flooded.)
My 'max won't be the same as yours but I do not pressurise the float bowl. Three squirts of the primer and half throttle. Pull string four or five times and it goes.
It will help us if we know: One or two carbs? points or CDI? Electric pump? Electric start? Choke or primer? If primer, bulb or plunger?
I have a pull-rope start 277, not a 447, but here's what works for me. The only way I can get it to start when cold is a squirt of pre-mix fuel directly in the carb. I use an old nasal spray bottle as my "primer" bottle. I probably don't squirt in more than about 1 teaspoon, if even that. Re-install the air cleaner, crack the throttle and it starts typically on the first pull. I open and close the enrichner as needed to keep it running as it warms up a bit, but generally it will go to a 2000-ish RPM idle in 15 to 20 seconds of running.
Before I ended up using this procedure I tried for an hour or more to get it to fire. I was using only the enrichner on the carb. I pulled and dried and replaced spark plugs I don't know how many times. They were always kinda wet so I thought it was already getting too much fuel. I don't know what to say but when I started using the squirt bottle my starting problems were over.
Same can certainly be done much easier with an actual primer, but I don't have one and am too lazy to add one.
Wow! You guys are good and helpful! One carb, electric pump, electric start, enricher, no primers. Previous owner set this dash up good! So the only thing I see different is that I never turned on fuel pump for a few seconds then off prior to starting. It’s a beautiful machine that has been consistent and perfect over the years. Let you know what happens next. He is going to meet me next time I’m up at my hangar. Green Sea SC here we come! I’ve got 3700 feet of grass runway to myself! Look up this beautiful piece of aviation beauty!!
Slip of the finger. Meant battery. Spoke to gentleman I bought it from since post he said sequence is turn on fuel pump and check for any pressure drop, forward on enriched valve, main switch on, clear prop then start with throttle forward and enriched valve off. After two tries he said battery would be drained and would have to charge and wait. Sound about right? Let me know.
Thanks!
What kind of battery? You should get many starts from a charged 12 amp/hour or bigger battery....not just two. Obviously, the battery isn't a part of the engines spark plug electrical system so it won't have any affect on the engine firing.
Your start procedure is strange.... The enrichener valve only works when the throttle is closed. The procedure should be "enrichener full on, throttle full off, crank engine until it fires and starts to run, close enrichener, open throttle".
Instead of an enrichener valve a pump primer works much better. I have even removed the enrichener valve and filled the hole with sealant to ensure that there were no air leaks there. Pump the primer a few times to inject raw fuel into the manifold and start cranking. When the engine fires continue pumping the primer slowly until the engine runs without further priming.
With CDI ignition ya gotta spin the engine over a little faster than with points ignition. I would check to see if you are getting a spark on a new plug. If you are then ignition may be noproplemo. If you have points and no fire at the plug it might be a couple different things. These guys are a world of knowledge on these types of troubles. Me; I am still trying to tie my shoes. Good luck!
When checking for sparks with the plugs out, with an electronic ignition they can be very hard to see. In fact I couldn't see them at all once, but they were there...
Well as it turns out, the stator was the problem. With wonderful assistance from Wayne Robinson out of MYR there was not a spark and the wire from the stator was burned. So if anyone has an extra stator (Rotax 996-844 or Coil kit P15W150) that works I really would appreciate a reply. The big aviation supply people want a fortune for these things. Many thanks for a reply.
Hah! Welcome to the world of "Aircraft Pricing." I also agree that a primer is the best way to go. Regrettably, I avoided using one for years.
The two 1/8" ports on the bing carb that allow it to breathe which connects to a three way tee. Blow into that line and your engine will be primed, assuming there's fuel in your float bowl
Looks like he got it figured out Jeff. No spark/ bad stator wire. Further up (if I read it right), you said something about the previous owner was going to (show you the way to start it) and you noticed the only difference was the turning on the electric pump & then turning it off again. Aside from spark issues, I will assume you know that by turning on the electric pump for a few moments (in the "start procedure"), is going to assure that your float bowls are filled to their upper most level vs. the cranking of the engine (to operate the vacuum fuel pump), to pull gas through to fill the float bowls. It doesn't take that many days for the fuel in the bowls to evaporate down a few centimeters & low fuel level in the float bowl can certainly be cause for delayed starts/longer cranking... I have a Zenoah G50 that went from being a real trick to figure out how to start with the (enrichener) lever and just how far to pull it out or it would flood real quick. Put in an ELECTRIC fuel pump and turned it on before starting. WOW! How easy to start after that! The (choke) is almost useless now. (YMMV) (JMHO) (FFT) TTT
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