Hi guys,

I figure I'll post here since I'm a "newbie" when it comes to glow.
I've been flying a while now (electric), and have even converted a SkyRaider Mach II and flew it well.

Most of the ppl here flow glow, so here I am.

I have a Saito 150 on my Sig Mayhem 3D, set up per instructions / manual. Today I was firing up the motor in anticipation of flying the thing tomorrow.

At first it fires fine, but I didn't remove the glow starter for a while, and then when I restarted it, the motor wouldn't start. I figure this is probably because of the glow starter battery died. I charged it for 1-2 hrs, and later it fires once, but when I advance the throttle, it died again and wouldn't start up again.

I am thinking that's because the starter battery died because I don't even get much any sputtering at all.

I guess my guestion is this:

How do you diagnose the different causes for motor not starting?
1. glow starter dead?
2. engine flooded?
3. engine not getting enough fuel?
4. need to change glow plug?
??? any other causes???

Thanks
Josh

1-2 hours on a wall charger is about enough for you to get an engine started once, if it starts quick. That thing needs an overnight charge, or a quick field charge. Once you get that solved, you'll have no problems. The engine died on acceleration probably due to the fact that it was cold, and needs to be warmed up slowly. Once warmed up, you may have to adjust the low speed needle slightly to get good transition, but there is nothing wrong with your engine. Saito's are good engines!.

To diagnose:
1. Glow starter battery--plug it into a loose glow plug (careful not to burn yourself) and see if the coil lights up.
2. Engine flooded--just use an electric starter. With an electric starter, there is no need to prime the engine. It will draw fuel and fire when it has the fuel it needs--no flooding (unless your glow plug is not lighting).
3. Not enough fuel--engine should start briefly, and then eventually sputter out and die.
4. Need a new glow plug--when the engine dies, or severely drops RPM after removing the glow driver, a new glow plug is needed. Caution--the same thing can happen if your fuel goes bad. i had some fuel go bad the other day, and my engine died every time I removed the glow driver. I changed glow plugs and the same thing happened. Finally figured it out--it was the fuel. now, if you know your glow driver is hot (from testing it, or if it has a meter), and you can't get the engine to fire even when it has fuel, then take the glow plug out and test it, it might be blown.

Hope this helps....

definitely helps.

Well, a starter is not in my budget right now (probably will need it later). But let's say there are no starter on the field at all, how do you know?

As I understood it, you adjust the fine needle to get the max RPM, then back off another 3-400 or so.

another important question, what size hex wrench do you use to leave on the engine, so that you can adjust the engine without having to remove the cowl?

Thanks again

I will make a suggestion to you.

Get a tach and use that to set up your engine. Due to the differences in sound, there are very few people who can set up a 4 stroke properly without a tach. A $20 investment is cheap compared to possibly ruining a $300 engine.

Once the engine is properly set up you should not have to touch the low end again, and the high speed needle should not need any more than a 1/4 turn to compensate for the differences in temperature and humidity.

FWIW - If a 4 stroke engine is not "making" smoke at ALL engine speeds, there is a very good chance it is being run too lean.

I am not familiar with the plane, but if it is cowled or partially cowled, run a piece of tubing from the vent nipple to outside the plane to keep the oil residue out of the engine compartment. The vent nipple is the nipple on the bottom of the engine about 1/2 way between the prop and the crankcase.

There is a huge thread on the Sig Mayhem. Here is the link. I bet you could get lots of help there...

http://www.rcuniverse.com/forum/m_14..._1/key_/tm.htm

Contrary to popular opinion, a starter is not a required piece of equipment for most engines. I've gotten along for years leaving mine at home (I bought it for boats, not planes). Occasionally I need it for starting a particularly stubborn (tight) new engine, such as the K&B 3.5cc that I've been breaking in, but mostly I don't use the starter on airplane engines. Learning what your engine wants in the way of priming will give you quick starts either with or without a starter. I always get a chuckle when I see someone stick a starter on the spinner and crank the engine for 20 or 30 seconds before it starts. Unfortunately, I can only imagine how much wear is being caused spinning the poor thing so long while it's dry.

Every one of my engines is slightly different when it comes to priming. Note, priming is ALWAYS done with the glow driver OFF. When I can get to the carb, I cover it with my finger and flip the prop the appropriate number of times. If I can't get to the carb, I cover the end of the muffler and flip the prop. The pressure in the muffler forces the fuel into the carb. For a new setup, such as a cowled engine where I can't get to the carb, I've found it's helpful to go through several cycles of staring with the cowl off. This lets me see how much priming it takes to get fuel to the carb.

Not sure what you mean by "fine needle", I've usually heard them called high speed and low speed (or perhaps idle). As has been suggested, having a tach is very helpful for setting the high speed needle. I tend to be conservative, I want my engines to last a long time and I don't want deadsticks from the engine running too lean at the end of the flight, so I back off a little more than 3-400 RPMs.

It's hard to diagnose engine tuning problems without being there, but my guess is your problem is a combination of low voltage on your glow starter and your engine being set too rich. I never had much luck hand starting engines with glow starters. Glow plugs are designed to be lit with 1.5 volts. Since the glow starters are powered by a 1.2 volt battery, they are at a disadvantage compared to a 1.5 volt battery, or even better, a power panel with adjustable output (this is what I use). The self contained glow starters seem to work best when used with an electric starter.

Anyway, if you combine low voltage on the glow driver with a slightly flooded engine, you've got a situation where the plug will not be hot enough for the plane to start. This is particularly true when the engine is inverted, the fuel can pool in the glow plug and without enough power, the element stays cool. When you encounter this situation, pull the glow plug out and have a look at it. See if it's wet, and if perhaps fuel comes out of the glow plug hole. If either of these happens, you know it was flooded. Put the plug in the glow starter and see how it does at boiling off the fuel. I know the glow driver in my power panel has no problem with this. Flip the engine over a few times with the plug out to help clear the fuel, put the plug back in and try starting it.

Once you get the engine running, procede quickly to getting the high speed needle set according to the manufacturer's instructions. One trick I've found for getting the low speed needle set is to see what happens when you remove the glow starter while the engine is idling. With the glow starter attached, run the engine to full throttle to clear out the carb. Bring it back down to idle and leave it there for 5-10 seconds to stabilize. If the engine slows and dies with the glow driver on, the idle mix is either way too rich, or more likely, too lean. Watching the exhaust should give you an idea which is true. If the idle is stable with the glow starter on, remove it. If the engine slows and dies, or slows significantly but the engine is able to keep sputtering, I've found that means the idle mixture is too rich. If there is no change when you remove the glow driver, it's either just right, or perhaps a bit too lean. Once you have the idle set so there is little to no difference in RPMs with the glow starter on or off, do the final setting of the low speed needle by testing the transition through midrange to high speed.

One that fits. Sorry for the wise a$# answer. You really can use anything that fits, including left over pushrod material. Note, if you use pushrod material, file a flat spot so the set screw has a place to bite, and so the rod won't come out even if the set screw loosens up a bit.

Hi BoneDoc I have the same setup on my Mayhem as you.I have the Saito 150.I have a starter but it is a small one and realy don't like too turn the big motor.It will start my motor when it is cold but I have too help it with a chenken stick when it warms up.like was posted above get you a tach and pick you motor and OPEN the high speed untill the motor slows 2 too 3 hurnder RPM.Hope this helps Joe.

Thanks for all the info guys, esp for the long post by you, Chuck.

Seriously, I didn't even know that you can scew those high speed needle holes . I thought you have to get a hex wrench of just the right fit... mark of a newb[:-]

Either way, I successfully maidened my Mayhem 3D, such a sweet plane, and I ran the engine on the rich side because I was there on the field by myself, and could not possibly (without a tai trap) do all the fine tuning myself. The engine never skipped a beat, nor did it ever hesitate or flame out.

I am officially a slimer now[8D]