Qualcast Suffolk Engine

[Paul1712 0]

Hello everyone.

I really need some help with my Qualcast engine.

I'm not getting spark, I have cleaned the points and replaced the condenser but still nothing.

As you can see from the second image I am getting resistance from the sparkplug wire to the base of the coil, but I'm also getting the same resistance from the open points.

Do I have a bad coil?

[mattblack 76]

Has it been running and then stopped? Or did you get it as a non-runner?

 

I can't see in the second picture where you have the other test lead, but there should be no continuity across the open points.

 

What's the purpose of the red lead with the sleeving on that's earthed on the condenser mounting screw?

 

 

 

 

[Paul1712 0]

Hello Mattblack,

Yes I got it as a non runner.

 

In the second pic I have the positive test lead on the spark plug wire and the neg on the base of the coil.

 

I thought the same thing about the sleeved wire, but that's how it was when I removed the flywheel.

I actually thought it's supposed to be the kill wire.

[mattblack 76]

Your pictures are the other way round, the the first one shows the test leads on the HT lead and earth (coil secondary windings test)

 

Looking at other pictures online that sleeved lead appears to be an earth lead for the coil?

 

Have you tried another spark plug? And is the points gap correct?

 

Not trying to teach you to sucks BTW, just trying to get my head around it! 

[Anglo Traction 998]

One of those red wires (likely the sleeved one) is possibly the coil earth IF the coil winding wrap is insulated from the soft iron laminated coil plate?.

If so, then the other red wire is from the coil's primary winding and services the breaker points.

The issue with the image references is the 3rd image that shows the COM lead point contacting the insulated half of the breaker point which is open, But you don't show or say where the Red  'V' lead point is contacting!.

 

I see that the smaller red wire is (presumably) spliced into the (black) condenser wire.

You should isolate the condenser from that lead if you want to test the resistance of the primary winding, which if ok will give you a resistance reading of approx 2 to 2.5. I don't have the actual value.

 

That test should be:-  Red point on the wire from the primary winding and the black COM point to an earth point.

Keep at it. I presume the magnet(s) in the flywheel are still strong enough to produce a spark?.

It's many years since i messed with one of these, I can't remember if the flywheel is 'Keyed" for fixed timing, or requires setting up. Wristpin is the man you need. Hopefully he will look in.

Regards

 

[Wristpin 399]

As far as I can see, the wiring is basically ok , just a bit untidy!  The wire going to the condenser anchor screw is the common ground for the primary and secondary windings of the coil. Flywheel magnetism - very unlikely to be an issue. Maybe I’ve been lucky but in 50+ years of playing with small engines , I’ve yet to find one where loss of residual magnetism has been the culprit. Even on Villiers on old Atco Standards , coils and condensers have been the issue , not flywheels.

Timing. As has been said, the flywheel and points cam are keyed to the crank, so no issue there. The timing of the spark ( points opening) for that engine is 22-24 degrees before top dead centre with the points set to the recommended gap .( 17thou? - it’s stamped on the flywheel) . The only adjustment for that is moving the stator plate in its slots . Chances are that unless it’s been messed with the stator is ok where it is.  If you want to check it , a timing disk can be printed out from the Internet and glued to a bit of card,  attached to the crank,  and the exact position of the points opening checked/ set  either with your multimeter or the proverbial fag paper ! The sequence is to set the gap first, then their 22/24 degree BTDC  opening.

I would double check that the points are really clean and the moving one is free to move on its pivot and making good contact when closed. Sometimes , due to wear on the heal of the moving point , it’s necessary to unscrew the fixed point and move the shim washers .

 

[Paul1712 0]

Thanks everyone for your feedback and very useful tips.

 

After much playing around and testing I finally got spark.

One of the main issues was the magnet on the flywheel had a thin layer of rust, once it was cleaned and the points adjusted it made spark.

 

With any luck I can get it to bust off.

Thanks all.

[Paul1712 0]

Got it to run!!!

[mattblack 76]

Good result!

 

I'm guessing the mower has spent some time outside? 

[Paul1712 0]

On 4/7/2024 at 5:41 PM, mattblack said:

Good result!

 

I'm guessing the mower has spent some time outside? 

Yes definitely.

I don't mind the look as long as it's functional.