# techumseh no spark



## corey700srx (Oct 26, 2006)

I have a snow blower with a techumseh 5 hp hs-50 from a relative that moved south. Has no spark/erratic. Some times it burps and trys to run.Does it neds points? Coil? Any help or manual would be greatly appreciated!


----------



## Cser (Oct 26, 2006)

Here is your manual for your model http://www.cpdonline.com/692509.pdf.
Its a start and has lots of info for your engine.
If you engine has been sitting a while you may only need to lightly sand the fly wheel where the magnets are and lightly sand the magneto,,,do not use emery cloth as it has metal particals in it...good luck.


----------



## 30yearTech (Sep 14, 2006)

Sanding or polishing the magnets and coil laminations will not make any difference! The only time you need to do this, is when you are setting the air gap between the coil laminations and flywheel magnets. Rust does not affect the magnetism and will not prevent a coil or CDI from operating.

Look elsewhere for a problem, if your unit has ignition points then that would be a good place to start, also pay attention to the flywheel key, if you have points a slightly sheared flywheel key can cause erratic spark. Check to make sure the kill switch is not causing the problem also.


----------



## Cser (Oct 26, 2006)

Lightly sanding makes a very large difference,,,but I did forget to have you check the air gap when you are done.
Gap should be.0125,,,tecumseh has a tool for this 670279 for checking it if you do not have a feeler gauge that small.
If you set the air gap with a rusty fly wheel you gap may change if the rust particals fly off,,,so clean the rust!!!!


----------



## 30yearTech (Sep 14, 2006)

Cser said:


> Lightly sanding makes a very large difference,,,but I did forget to have you check the air gap when you are done.
> Gap should be.0125,,,tecumseh has a tool for this 670279 for checking it if you do not have a feeler gauge that small.
> If you set the air gap with a rusty fly wheel you gap may change if the rust particals fly off,,,so clean the rust!!!!


 

Now, how about some of those old wives tales that just aren't true. 

* Rust on the flywheel magnets causes a loss of spark. Not true. A magnetic field does not care about rust. It has no effect on it.
* A bright blue spark is best. A yellow/orange spark signifies weak ignition. Not true. Spark color determines virtually nothing. The hottest spark is ultraviolet which we can't see. Blue spark is cold in comparison to ultra-violet. Orange and yellow come from particles of sodium in the air ionizing in the high energy of the spark gap.
* Laying the spark plug against the block and pulling the engine over can adequately test ignition coil output. Not true. The ignition coil will only generate enough output to jump the gap of the plug. When under compression, the plug requires twice the voltage to fire. This check is not an accurate test of the coil and can be misleading.
* An armature air gap that is too wide will prevent spark. Not true. Well, sort of not true. Briggs & Stratton air gaps cannot be made too wide to prevent spark providing the coil is healthy and the engine is spun over fast enough. A wide air gap, say .030" will ever so slightly retard the ignition timing as the magnetic field takes longer to build within the coil windings.

You can read the entire article at 

http://briggsandstratton.com/display/router.asp?DocID=67479

It covers basic ignition system operation although for a Briggs engine, the same principles apply to all brands of igntion systems. :thumbsup:


----------



## newz7151 (Oct 15, 2006)

30yearTech said:


> Orange and yellow come from particles of sodium in the air ionizing in the high energy of the spark gap.


Hmmm... now, what do you suppose would happen if you had a spark tester and a little pile of salt to set it in while you pulled the flywheel over?


----------



## 30yearTech (Sep 14, 2006)

Lets see add a little tequila, lime juice, and triple sec to the salt, pull the rope and I bet you get a margarita with one hell of a kick!!!!! After that I bet you won't care what color the spark is lol....


----------

