3W-100 B2
 

Does anyone know how I can test the ignition on this puppy?
I bought this engine from a guy here on rc universe and it is supposed to have less than
2 gallons thru it .The engine looks fine and the mufflers look great to even the ignition
looks good. I just can not get this thing to fire.
I am running 4.8 volts to the ignition and I know it is getting to the box, but how can I find out
if it is getting to the plugs?
I have looked at the plugs and they look fine to me.I am running 50:1 lawn boy ashless
have a three line set up from the tank it is getting fuel.
What else came it be?
I have run a voltage meter to the leads up to the box and it is getting good volts.

RE: 3W-100 B2
 

Have you tried this? Remove the plugs, put the caps on the plugs, rubber band the plugs to the cylinders, turn the ignition on, turn the prop through 360 degrees. Did you see a spark? You may need to do this in a shady or dark place to see the spark.

No spark? Recheck your wiring. Still no spark? Get your money back, send it in for repair, or find a friend familiar with gasoline engines who will look at it with you.

Ken

RE: 3W-100 B2
 

Maybe I am running to small of a battery pack fpr it to power the battery.
Does the mah make a difference on the ignition?

RE: 3W-100 B2
 

1400 ma or above will be ok

RE: 3W-100 B2
 

I assume this is an older 3W-100 with one magnet on the crank hub. This means the old style ignition. This ignition uses an inductive pickup coil for a sensor and requires some rpm before it will spark. If you remove the plugs to test for spark, you have to give the prop a healthy flip. Also, test in a dark location. The spark is a little feeble and it's impossible to see in sunlight. The system grounds through the outer cap metallic shield, so you don't have to hold the plugs against the engine when testing - just make sure you put the plugs in the plug cap.

RE: 3W-100 B2
 

Thanks guys for the replies.

I am getting good spark.Talked to AI and they said to take the prop off and pull the plugs
out and rotate the hub back and forth quickly and you should get spark.And I did and there
is spark.
Let me ask you guys this does any one run a pump from the tank to carb?
And yes this is the older 100 engine.

RE: 3W-100 B2
 

After all that has been said, could it be that you aren't choking it enough? Try this: Idle, choke on, ignition on, flip until it pops. Idle, choke off, ignition on, flip until it starts.

Ken

RE: 3W-100 B2
 

The carb has a pump inside - no external pumps required. Take a look at your fuel line as you flip the prop with the choke on and ignition off. If it doesn't pull fuel easily from the tank with each flip of the prop, something is wrong. Look for an air leak in the fuel line from the tank.

RE: 3W-100 B2
 

If you have an inline fuel filter..remove it. Filter the fuel as you put it in.

RE: 3W-100 B2
 

What's the problem with inline fuel filters? I've been using them for years. All of the weedwackers and chain saws out there use a felt clunk filter. The location of the filter shouldn't make a difference as long as it doesn't leak air and prevent fuel draw.

RE: 3W-100 B2
 

Ditto!

Bruce

RE: 3W-100 B2
 

I got it figured out guys engine runs great.
Took the carb off the engine and tracked the fuel all the way threw it.It was pulling fuel to the carb but not enough.Anyway it was as many of you know a stuck diapraghm on the back side of the carb.Took a little gas and soaked everything up and put it back together and she popped
on the third flip,started on the second engine runs great.
I think what caused the problem was that the engine was still in the break in phase when the engine was put up to be sold, and the high oil content was holding it open.

Thanks guys for all your help.

RE: 3W-100 B2
 

Diablo and cu.in., I used the filter pictured here on my 3W-75i, and I am under the impression it caused me three flameouts. I removed it and haven't had any problems since. it was new, clean and located two inches from the tank.