Hi,

I have a Mangum Xl .40 that wont start up now. The plane flew fine last sunday but it wont start today!. When i use my electric starter the prop spins really fast but as soon as i let go the prop starts. This is my first engine problem so all i have checked is the glow plug which glows orange

Thankx

Make sure you don't have the negative and positive wires for the starter switched on your power panel. Could be spinning the engine backwards. Don't ask why I suggested this. :stupid:

The starter is connected ok. The prop spins the right way. Any other ideas????????

Typical reason for an engine not to start (if glow plug is good) is lack of fuel try putting a couple of drops directly in the cylinder head i.e. in the hole where the glow plug goes. if it starts and runs for a little bit the fuel system/Carb should be checked out

is it common for 1 day it runs totally flawless and the next day the fuel system goes wacky

Creative swearing and threatening the engine with a ball-peen hammer. Do this with a new engine as soon as you take it out of the box. Tell it welcome to your world.

Over the years with these little engines I've found that whats common about them is a VERY relative term. things like temeperature humidity and fuel quality can effect operation from one day to the next also if it's a new engine and not yet broken in performance can be erradic the best advice I got is reset the high speed needle to the number of turns suggested in the instructions and try again.

Some of the best days of my life were spent fiddling with a Cox .049 in a field... go figure

The engine started thankx to some drops where the glow plug goes

You can do the same thing by disconnecting the power to the plug, put one finger over the hole in the carb, turn the prop a few times, then reconnect and start. It takes time to get fuel through the line sometimes. This helps.

If it started and kept running after doing that it sounds like it wasn't primed enough or at all. In the future with the glow igniter OFF cover the carb with your finger and spin the prop watch the fuel line till the fuel reaches the carb and you finger has a litttle fuel on it. Don't flood it which could cause hydro lock and damage the enginge/Crankshaft connecting rod.

Ok i got you. Thankx

I don't know about the Magnum .40, but I can tell you the Magnum .28, .25, and .15 all like a very very sloppy prime. As stated above, with the glow starter off, go to full throttle, cover the intake, and rotate the prop by hand until fuel gets to the carb. Then, on my Mags, I turn it 4 or 5 more times. If you listen, you can hear the fuel squirt in to the carb. The extra turns gets the fuel all the way up in to the combustion chamber. After that, you should be able to hook up the glow starter, reduce throttle, and start it right up.

For what it's worth, I prime my engines by covering the muffler outlet. Builds pressure in the tank and pushes the fuel to the carb (rather than relying on vacuum to pull it).
Dennis-

Another Problem!!

I flew my plane yesterday with an instructor. Ot was a VERY humid day 30 plus degrees. Nearing the end of the flight the engine stalled. My instructor said that everyone that day had experienced dead stiks. He also told me that he heard a pop sound when the engine gave up but noting came or poped off. He told me to start it just to make sure nothing was wrong. I emties the tank and tried to start it. It seemed the starter was slipping off the cone. I need to start it before rust starts to kick in from the moisture>

Don't worry, It's not going to rust just because you ran it on a humid day.

I think my post was confusing. I wasnt worrying about the humidity i was worried about fuel not empties from the engine. The instructor said to run it dry but i cant start it up

I have never run the fuel out of an engine after flying. 27 + years and never had a problem. I think you do more damage running out than leaving it in. Friends that run it out are always replacing bearings. The newer guys always run it out. It is based on how you learn, and thats how I was taught a long time ago.

thankx for the tip. Im trying to get it going again but my starter wont turn it over. The starter runs but could it be the battery supply. And it seems to slip off the cone is there non slip ones out there. Whenever i press hard it just grinds the plastic and leaves a wite mark

Back the prop away from compression to give the starter a running start, that frequently helps.

Before applying the starter, can you turn the engine over by hand (with the glow starter removed?) If not, something is seriously broken in the engine, and cranking with the electric starter will make it worse.

Take the glow plug igniter off and try to trun it by hand.

If you can and it doesn't feel bound up then you might want to recharge your starter battery.

Take the glow plug out if it binds and spin the prop with your starter to clear a flooded engine. Put a rag over the head or else you'll have fuel in the face also disconnect fuel line from carb.

I can turn it over by hand . I cannot feel anything bound up. Ill try recharging the starter battery and see if it helps.

Im quite amazed at how quickly i get answers to questions. RCU is simplly THE best board for beginers.

When you meen bound up are you saying i wont be able to turn it ?

Ok Guys, it turned out to be the starter battery was low. Sometimes we think of the most complex solutions when the answer is so simple it makes us feel dumb

Thankx for the quick replies