Electro mechanical problem no ignition on old engine

[SimonTHK]

Hello electro tech online. I dunno how much this quistion is related to the forums but great help has allways to be found here so far

I have an old engine and the sparkplug wont make any sparks. So I measured with my measurement tool if I could measure any HZ between ground and the sparkplug head when I pulled the pull noir (the leash). It worked fine and showed me some HZ depending on how fast I draw. So I guess the connections is allright...
Then I measured the resistance between ground and the sparkplug head, which was 6,5k. Probably individual for any engine, but what else can I do? Do I even have any chance to repair this, when the engine is too old for spare parts?
Could bad coils (in some way) cause this problem?

 

[alec_t]

This may help:
https://www.clarks-garage.com/shop-manual/ign-04.htm

 

[SimonTHK]

I think I came to a half conclusion. The magnet on flywheel seems very weak, I cant imagine it should be able to create a spark.

 

[Sangoma]

Check the points are opening and closing and that they are clean. They should open about 15 thou.

Resistance on the plug lead is OK, many have higher for suppression.

Put the end of plug lead near the engine, and you should have a blue spark at least 50 thou long. The plug gap should be around 25 thou.

Check the wires at the points and condenser, and if there is a pigtail wire grounding the points plate.

Magnet does not have to be super strong, some old ones were quite weak by todays standards. Check for rust powder on the flywheel and coil poles.

 

[SimonTHK]

Check the points are opening and closing and that they are clean. They should open about 15 thou.

Resistance on the plug lead is OK, many have higher for suppression.

Put the end of plug lead near the engine, and you should have a blue spark at least 50 thou long. The plug gap should be around 25 thou.

Check the wires at the points and condenser, and if there is a pigtail wire grounding the points plate.

Magnet does not have to be super strong, some old ones were quite weak by todays standards. Check for rust powder on the flywheel and coil poles.

I get no spark ever I read that many people have problems with old magnets, so I will try look more into that. Luckely I have some very similar laying around

 

[MikeMl]

I think I came to a half conclusion. The magnet on flywheel seems very weak, I cant imagine it should be able to create a spark.

The gap between the pole piece and the flywheel is extremely critical. I use one to two sheets of paper (~0.004") to set that gap on my Briggs and Stratton...

 

[SimonTHK]

The gap between the pole piece and the flywheel is extremely critical. I use one to two sheets of paper (~0.004") to set that gap on my Briggs and Stratton...

In what way is it critical? A stronger magnet further away should be able to do the same job I guess!

 

[MikeMl]

In what way is it critical?..

A bigger gap results in hard starting due to weak spark a slow speeds.

 

[tcmtech]

Your condenser could have went bad also.
Then there is the possibility of there being more than one problem with the system as well. Doe sit have a independent wire coming off of the ignition system that is used to shut the engine off and if so is it pinched rubbed through or shorted out in any way?

What brand and model of engine is this and how old is old?

 

[KeepItSimpleStupid]

What model helps. Stuff is usually available. A few years ago, I upgraded an old engine to electronic ignition. I'm running engines that are 38 years old.

A spark plug wire break at the coil from bad assembly or removing the spark plug a lot happens.
Rust on the flywheel magnets is another.
I use an index card to gap after lightly sanding the flywheel/magnets.
The spark plug wire is usually resistive.

You have points and the condensor which both contribute to spark problems and you have to watch for the stop switch circuit.

The points switch ground to a cap that's grounded. The condensor discharges into the coil when the points open.

So, the primary is fed through the points/cap and the secondary the spark plug wire. Both share a common ground.

 

[SimonTHK]

Your condenser could have went bad also.
Then there is the possibility of there being more than one problem with the system as well. Doe sit have a independent wire coming off of the ignition system that is used to shut the engine off and if so is it pinched rubbed through or shorted out in any way?

What brand and model of engine is this and how old is old?

The engine seems very similar to this one **broken link removed**

Clinton engine 4 stroke B830 Modelnr: 498 1301 096

 

[SimonTHK]

Your condenser could have went bad also.
Then there is the possibility of there being more than one problem with the system as well. Doe sit have a independent wire coming off of the ignition system that is used to shut the engine off and if so is it pinched rubbed through or shorted out in any way?

What brand and model of engine is this and how old is old?

Actually it seems that the shut off wire is constantly connected to ground.
The button that it is connected too lead the shut off wire to ground. But when I cut the wire before the button I can measure ground on the shut off wire, which I find weird cause why should it when the button leads to ground?

Maybe there is something wrong here behind the flywheel on the cdi. But I cant get in there today.

Could it be, that the reason why I then can measure something on the spark plug wire, is because a very small current is running through my measurement tool but then rest runs through ground and doesnt allow my spark to get any "juice"?

 

[KeepItSimpleStupid]

The primary is of low resistance. 0.6 primary and 8K secondary. See: https://www.mytractorforum.com/showthread.php?t=88762

The shutoff wire by itself should change state. Usually it grounds the points when pushed. Just make sure the shutoff button works before starting the engine. I had an oops once. My replacement throttle cable really doesn't have enough travel, so it didn't hit the shutoff pin in off. I had just changed the oil and tried to start the engine and I could not turn it off without pulling the plug wire. That's risky too without something to grab it with. Meanwhile it's spewing oil all over me.

 

[tcmtech]

The shut off wire should not be connected to ground unless you don't want any spark. When it's connected to ground its the same as having your points closed all the time which is one reason you would not get any spark.

As far as Clinton engines go there are parts still available online. I did a quick search and came up with a number of sources so they are not that hard to find plus eBay is full of parts too including points condensers and ignition coils.

 

[SimonTHK]

The shut off wire should not be connected to ground unless you don't want any spark. When it's connected to ground its the same as having your points closed all the time which is one reason you would not get any spark.

As far as Clinton engines go there are parts still available online. I did a quick search and came up with a number of sources so they are not that hard to find plus eBay is full of parts too including points condensers and ignition coils.

I do not believe my engine has points nor condenser. Even though it is an old engine I think it uses a CDI. I am not that much into this yet, I will try and get off the flywheel today and see if there is anything else but magnet and CDI..

 

[KeepItSimpleStupid]

This https://www.clintonengines.us/Home.html might be useful for you.

 

[tcmtech]

I doubt its got a solid state ignition system. Those didn't come into being until the 90's a decade or so years after the last Clinton engine was made. More likely the points and condenser system are located under the the flywheel.

If it is a solid state ignition coil system its a refit off of another brand like a Tecumseh or B&S.

 

[SimonTHK]

I doubt its got a solid state ignition system. Those didn't come into being until the 90's a decade or so years after the last Clinton engine was made. More likely the points and condenser system are located under the the flywheel.

If it is a solid state ignition coil system its a refit off of another brand like a Tecumseh or B&S.

Yea ofcourse it wasnt solid state ignition
The points seems in very good shape and with 1 - 1,5 mm gap whem open.
Also I measured good resistance in the coil.
So maybe the condenser is my problem, but is there anyway I can test or measure if it is in good shape?
Also a condenser is similar to a capacitor right? I should be able to just change it with a working capacitor? Though I cannot find any information on the condenser. How much voltage would you estimate the condenser to be able to handle?
Thank you

 

[SimonTHK]

I just read this from google somewhere When the points open the flow of current stops causing the magnetic field in the coil to collaps. This induces the spark. When the capacitor (condensor) is added it will absorb a charge causing the field to collaps more and faster and will induce a hotter spark. Also as mentioned before it will supress arcing at the points. I've used to ohmeter method of testing many times.
This is not how I imagined the capacitor/condenser to work. Though it makes great sense and I should be able to add any capacitor with enough capacity instead of the condenser. Though I still do not know if the condenser if of high voltage or low voltage, since it depends on which side of the coil it is placed on.
Anywho I will just put a link in here that can help out anyone else reading this thread https://www.smokstak.com/forum/showthread.php?t=21175&page=1

Edit: Aaaand I read more up on it, the link really comes by alot. Seems an oscillation happens between condenser and coil, tus making the condenser size some way critical, on the other hand, condensers that old can vary ALOT like 200% ..... and so on. Anywho I better read more up on it or find a replacement condenser on ebay

 

[KeepItSimpleStupid]

Simply loose the points and the condenser. I've used these modules: http://www.mytractorforum.com/showthread.php?t=115151 There are a number of varieties for different kinds of engines. I did a conversion a few years ago on a 35 YO mower and I've really been pleased.

ebay, wherever: **broken link removed**

http://www.amazon.com/Mega-Fire-Ignition-Module-UNIVERSAL/dp/B001OK9ZFG

Vibrator caps were rated to 1200 or 1600 V, such as these:

And then there is this guy selling these: http://www.jerry-howell.com/IgnitionModules.html

Go back to when I was 10 YO and hadn't heard of a capacitance meter and I had a VOM back then at 50K ohms/volt. If you find the cap shorted via a resistance measurement, it's BAD. If you test with an ohmmeter on a low scale and reverse the leads and get a "blip" then it might be good.

The caps are HIGH voltage. Think of it this way. if you had just the magnets and a coil, your generating electricity. the idea is to store this electricity in a capacitor. Now, when you OPEN the cap, the cap discharges into the coil.
So, it's kinda like generate, store and use as a pulse.