Ohlsson & Rice: Electrical Test for Coil & Condenser

[CNew 403]

Hello,

    I’m trying to get a 13B engine ready to run and I’m not able to get spark. I cleaned the points really well and sanded the gently with 400 grit sand paper. I’m wondering if the condenser or maybe even the coil is bad. What should the numbers be if I use a volt meter to test? And, is there a recommended procedure to get the proper measurements?

 

As a side note, the coil does appear to have been repaired at some point in the past with some sort of epoxy putty applied to the side where the high tension lead goes into the coil. I have not tried to remove this yet and would like to test the coil somehow before going any further.

 

Thanks,

clint

 

[factory 483]

Is the points gap set correctly? , make sure there are no loose connections, etc.

 

To test the coil is OK you need something (like a multi-meter) that will measure resistance (in ohms & kilo-ohms), a good coil will have a very low resistance in ohms for the primary and a reading in kilo (k) ohms for the secondary, I haven't given any values as they tend to vary depending on the age of the engine (I suspect they changed supplier for the coil over the years).

Please let me know the readings you obtained if you are not sure.

 

Multi-meters aren't usually any good for measuring capacitors (also don't always have that function), cheap ones can give false readings if the capacitor is electrically leaky. Note that multimeters only test with a low voltage, so you can't tell if the insulation is leaky/failing at the normal operating voltages.

 

Here is some info for setting the gaps for all the various types of O&R engine;

 

 

1 hour ago, CNew said:

As a side note, the coil does appear to have been repaired at some point in the past with some sort of epoxy putty applied to the side where the high tension lead goes into the coil.

 

Have you got picture showing this?

 

David

[CNew 403]

Hello David,

     Thank you for providing the specs, this is very helpful.  I checked the points again and they look to be gapped at 0.020 and I also verified the 0.010 clearance between the coil and flywheel.  I’ll play around with my multimeter next and see what kind of numbers I get on the coil.

[CNew 403]

Hello David,

    I just took some measurements and here’s what I’m getting:

Primary: 7.5-8 k ohms

Secondary:  6-12 ohms. I has some trouble getting a decent reading on the secondary depending on where I touched the leads. I grabbed a second meter and repeatedly got nothing or at best 0.1-0.2 ohms. Both meters gave me the same result on the Primary.

 

Clint

[factory 483]

That's odd, the secondary (to spark-plug lead) should be the one reading 7.5-8 k ohms.

And the primary (to points/capacitor) the low value, probably too low a value for a standard multimeter to measure.

Please confirm this.

 

The meter that gave 6-12 ohms, check resistance of the meter leads connected together, if it still reads 6-12 ohms then either the leads are faulty or meter is faulty on that range (or you may be able to zero it if it has a control for that).

 

If it is 7.5-8 k ohms for the secondary (to spark-plug lead) then it should be OK and the repair is good.

 

Another thing to check, is the flywheel key present? This set the correct position the the flywheel on the crankshaft.

If you want to check the capacitor, I would suggest swapping it with a known working one to confirm if it's any good.

 

David

[Webhead 95]

Can we see a picture of how you installed the points?

[CNew 403]

David,

   My mistake, I accidentally swapped the values between Primary and Secondary. They should be as you suggest. I do have the flywheel key in place so that shouldn’t be good for correct positioning. I also tried a brand new condenser and still no luck. 

 

Webhead,

    I’ll pull it all back apart and take a photo of the points.  When I removed them for cleaning I only took out the springy piece with the copper metal which gave me access to both sides of the points without taking out the entire assembly. I was intentionally trying to avoid unnecessary adjustment.

 

I’m still scratching my head on this one...

 

Thanks,

Clint

[CNew 403]

Here is a photo of the points. I checked the gap again and I’d say it is between 0.018-0.020. Should I fiddle with it more to try to get more consistent 0.020?

[Webhead 95]

It's not that critical, the gap. What about your coil gap?

I have beat myself up in the past, trying to get spark. Very frustrating and it never turned out to be the coil or condenser. I did have points one time that just would not work, due to finger oils and aging. Maybe try to clean the complete points assembly. What turns the engine off? Is there a grounding switch that may be making to ground?

[CNew 403]

Thanks Webhead, 

     I’ll give everything another thorough cleaning.  The engine has a little kill switch lever for turning it off.

 

Clint

[Webhead 95]

It looks like it is touching the case. I could be wrong. I cannot see the 2nd wire, either. Just observations from the photo.

[CNew 403]

Sorry about the poor photoquality; I noticed that as well after I uploaded it. I verified that the lever is not touchingly the case, there is about 1/8” gap. The 2nd wire is also there but hidden by the shadow.

 

More tinkering ahead....

[CNew 403]

Well, I tore it all apart again and gave every single piece a thorough cleaning, polishing, degreasing, etc. - not sure it could be any cleaner. I also cleaned every connector, contact post, screws, nuts, etc. put it all back together and readjusted the points gap and the coil gap and unfortunately still no 🔥.  I’m starting to wonder if the points are defective. I resurfaced them again as well and really made sure they were clean and flat.  I may try adding the new condenser again but I’m not too hopeful since it didnt seem to help the last time I attempted it. I tried a new spark plug too.

[factory 483]

Probably a daft question, but have you got the case of the capacitor attached somewhere to the engine block? As it's fitted to the covers on this late model 13B engine I can't help thinking that it may be disconnected, as you probably have the covers removed to be able to turn flywheel to check for spark.

 

David

[factory 483]

12 hours ago, Webhead said:

I have beat myself up in the past, trying to get spark. Very frustrating and it never turned out to be the coil or condenser. I did have points one time that just would not work, due to finger oils and aging. Maybe try to clean the complete points assembly. What turns the engine off? Is there a grounding switch that may be making to ground?

 

I've definitely got an open circuit coil here, not surprizing really given how some people treated these engines, water damage is common in the UK too if they where abandoned in the hedge, damp leaky sheds, etc.

 

Using the resistance function on a multimeter would have proved if the points weren't making proper contact when closed (with coil wire disconnected on the back) or find a short-circuit if one of the little insulators was damaged (again with coil disconnected).

 

1 hour ago, CNew said:

Well, I tore it all apart again and gave every single piece a thorough cleaning, polishing, degreasing, etc. - not sure it could be any cleaner. I also cleaned every connector, contact post, screws, nuts, etc. put it all back together and readjusted the points gap and the coil gap and unfortunately still no 🔥.  I’m starting to wonder if the points are defective.

 

Here are all the bits that should be present for the points, if any of the insulating washers or bushes are damaged or missing you will also get no spark, also make sure the pushrod operates freely to open/close the points (the flat end goes towards the crankshaft).

 

 

David

[CNew 403]

David,

    Thank you for all the great suggestions.  I’ll have to play with the coil and points a small you suggest with the multimeter.  I think I’m understanding how you’re recommending testing it.  It would definitely be nice to be able to determine if the points are working.  

 

I can confirm that I attached the condenser to the engine. I tried two ways: 1) screwing it to the body of the engine in a threaded hole right next to the kill switch (my Groomer engine has the condenser mounted in this location as well) and 2) putting all the covers back on and screwing the condenser back where it belongs/was originally attached up near the head in the same area as the coil. 

 

Thank you you for the photo of all the bits as well. I can also confirm that all the pieces and insulators are in good shape and assembled correctly. Turn the engine I can see the points opening and closing so I believe the little push rod is working correctly.

 

I really appreciate you sharing all the great suggestions and help in sleuthing this one out!

 

Thanks,

Clint

[CNew 403]

Ok, so finally some success. Perhaps this is known and understood by other but I found the solution to be a little odd.  Basically I pulled the recoil starter off my Groomer engine and attached it to this 13B engine. Wah-la -beautiful blue spark!  I’m understanding this to be due to rotation speed needed by the flywheel to g t the coil going.  Simply spinning the engine by hand wasn’t sufficient to generate enough speed.  Does this make sense to others?  What led me to this was I was cleaning up the points on my Mustang 149 and ran into the same issue, no spark no matter what I tried.  As soon as I put the recoil back on it gave me hot blue spark. 

 

Clint

[Webhead 95]

I could never get a spark by hand. These are the things that you will learn along the way. Eventually, you may acquire the "O&R Master" title, at least in the States.

[CNew 403]

Yes, they are indeed finicky!

 

I’ve got a long way to go to being any sort of “Master”!  I am learning a great deal from you and David and appreciate you both sharing your knowledge with a new enthusiast like me.

[CNew 403]

After some painstaking carving and clean-up I think I’m just about ready to try my own hand at repairing the coil. I was able to remove most of the old putty stuff that wasn’t done well at all. I’ll go back in with some Locktite epoxy putty or some such concoction to see if I can get it shaped better and looking more original.

[factory 483]

Looks like it got dropped or something, make sure whatever epoxy you use is non-conductive for obvious reasons.

 

David

[CNew 403]

That was my guess too- I was a little surprised that there wasn’t more damage to the coil or the engine in general.  I’m looking at some Locktite 1999131 All Purpose putty as a possible option.