Suffolk magneto woes
I've just rebuilt two of my three Suffolk 75G14 engines. Before overhaul, one was working OK then just stopped for no apparent reason. The other hadn't been used for about 10 years, was a real pig to start, then refused to restart after the first mow.
In both rebuilds, I refitted the original magnetos as both looked physically OK. But, neither engine would start after rebuild. One produced no apparent spark at all, but the other did show some kind of spark.
Luckily I remembered I had two later 98cc engines under the bench, which are scrap because the previous owners (a) ran one with no oil and (b) left one outside with the spark plug out, so the bore corroded due to water. Anyway both still had their breakerless magnetos. I retrofitted both of these to the two 75G14s - a straight swap - and both burst into life first pull and run like Swiss watches.
So, it would appear that both original magnetos were either dead or very weak, despite looking in good order. Is there any way of testing these, and if so how please? The cost of a new one off eBay is about £20: you can buy a complete engine for this.
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Suffolk mags
Unfortunately no, they don't have separate coils and condensers, so I guess they're both destined for the scrap bin! Thanks anyway.
Suffolk mags
Pity, but I have just had a thought!
If the embedded capacitor has shorted out you are stuffed but if it has gone open circuit it is just possible that you could add an external one. If there's not room within the mag it could always be hung outside - just needs a wire to the points where the coil primary fixes. I've never done this but I don't see why it shouldn't work!
Mind you if the coil itself is "down" you're still out of luck! Have you tried leaving the "dud" coils in a warm place for a week or two to thoroughly dry out - sometimes works.
Suffolk mags
Hopefully you have the older style mags with separate coils and condensers. Later ones have the condenser embedded in the coil so a faulty condenser writes off a good coil.. Coils and condensers can be tested with specialist equipment which would have been found in most garden machinery workshops but with electronic ignition having been around since the late 70s i suspect such kit is becoming rarer.Resistance of the coil primary and secondary windings can be checked with a cheap multimeter - someone may know what sort of values apply but you can always compare yours against a known good coil. Condensers can be tested with a capacitance meter but new one are cheap so substitution is probably the answer.
Attached image is of a condenser on test last weekend!