Miss Engine - Help Needed

[JimDobson]

G'day all, I have taken more than a few days to build the base for this 6cc Hit & Miss Engine. Really happy how it turned out. I can't get a spark from the plug. Has anyone got any thoughts on what to check out to see why I'm not getting a spark? I've pointed out in the video a few things where I'm stuck.

 

[Jasonb]

Check where the wires are soldered to the switch could well be shorting there either to other parts of engine or to themselves

Their ignition modules are built for Hall sensors that have 3 wires but the contact type switch only required two of those

 

[JimDobson]

Check where the wires are soldered to the switch could well be shorting there either to other parts of engine or to themselves

Their ignition modules are built for Hall sensors that have 3 wires but the contact type switch only required two of those

Thanks Jason appreciated. That red wire not being connected had me worried. Now that I know that, at least I can rule that out.

I've checked a fair things, checked for as much connectivity with a multimeter as my knowledge will allow....just can't find why its dead as a door nail.

 

[Mike1]

You seem to have checked out everything, wiring, battery, but I notice you are rotating the engine in a anti clockwise direction during the test, should the engine be rotated clockwise when facing the flywheel as you are in your video.
Mike1

 

[michael-au]

This is how points and coil should be wired, not sure about the module you have under the engine

you might find some useful info here How To Wire Up A Sparkie


That is how mine is wired

 

[Jasonb]

The modules work a bit differently. They are built to also work with a hall sensor which requires three wires. Wen operating with contacts only two are needed the black & White +ve an d-ve, the red signal wire is not used.

The other wires form the module are an earth wire (looped to head screw) and the HT to the plug. And two to the battery with switch in that loop.

Also worth checking that the wire in the spark plug boot is actually making contact with the plug

And as said convention is top of the flywheel rotates away from the hopper

 

[michael-au]

The point work like a switch, the earth wire would go through the points, so the earth wire opens and close, when the close it puts power through the ignition and creates the spark for the coil,
if the modular is ment for hall effect sensor then it might not work with points

 

[Jasonb]

No The earth is separate on most of these modules be they S/S, Minimag, Far Easytern and that is what teh black wire with the looped connector is.

The two contacts not points do act like a switch but they are far lower current than you find with point sso don't need tungsten contacts as the spark if any is so small. If you look at the way that set of contacts is constructed both arms are held by insulated blocks so they should not be in contact with the engines frame or part of the earth circuit. They are just the + and _ of the hall sensors 3 wires and depending on how the circuitry is done you can run using just the two wires though some modules do need an additional resistor (Minimag).

See this PDF, when using a simple contact or wiper contact then you just use two of the three hall wired. EARTH and HT are separate wires

https://minimagneto.co.uk/documents/MCL-1R4.pdf

 

[JimDobson]

Thank you one and all for the comments and suggestions, they are very much appreciated.
My other hit & miss engines have the Hall sensor so this reed switch is new to me.
Also this is where my very limited electronics knowledge bites me on the proverbial.

Is there any setting on a multimeter to put a probe on the spark wire to get a reading? (apologies upfront if that is a stupid question).

I'm happy with the hours (days) I put into fabricating the wooden base for the engine and dearly want to get this engine running and do very much appreciate the advice and help.

One more question someone told me that the 3 x 1.5v batteries isn't enough voltage (that's the battery harness that came with the engine though and what others are successfully using) and wrote to me "the yellow box needs 7.4v voltage, you can buy a 3.7v battery for the battery holder".

 

[Jasonb]

Test method http://cncengines.com/images/sparktest.pdf

Not seen CDIs that need more than 6V though make sure your batteries are 1.5V not rechargables than are closer to 1.2