Rotovator Magneto

[forestboy]

I've been given an ancient rotovator - no identifying markson it whatsoever. It's a 4 stroke and it all seems in good condition, not seized etc, but there is no spark and a resistance test on the magneto the shows it is kaput, although it does seem to throw some voltage out 3 or 4 volts maybe. I have no clue of the magneto type - is it okay to just bang any old magneto that fits on there from e.g. a lawnmower?

 

[Burnerman]

We’ll need pictures of what you have, I’m afraid......I’d guess you are dealing with a flywheel with contact breaker points underneath?
John

 

[forestboy]

We’ll need pictures of what you have, I’m afraid......I’d guess you are dealing with a flywheel with contact breaker points underneath?
John

Hi John. Yes, that is correct. Here is a picture of the magneto itself - the exposed wire I pulled out of the flywheel. I'm getting 2.62 reading on the earth wire, zero on the body.

 

[Burnerman]

At a guess, I'd say that was an early Briggs and Stratton ignition coil, though Villiers did use a similar item at one time.
If the machine has contact breaker points then it is these that sets the timing - they are opened and closed by the cam underneath the flywheel.
I'd think grafting on a modern igniter (which is solid state) would be pretty difficult to get the timing right - but of course I've never tried it!
At least you would need an igniter that matches the flywheel diameter.
I think a good way forward would be to try to replace that coil like for like if you can.
There are probably a few vintage machinery dealers about.
A few more pics of the motor may help us with the identification - and for sure this is an interesting project!
John

 

[forestboy]

I think I have located an original part but it is £60, more than the machine is worth I think

 

[Burnerman]

For sure, that’s an early Briggs horizontal crankshaft engine....many applications, including the Baromix mini mixer.
John
I’ll edit, it’s for around a 2hp engine, seen one on eBay for around £17 I think.
J.

 

[Burnerman]

Is this the one?

briggs and stratton 2hp Ignition Coil | eBay

<p>briggs and stratton 2hp Ignition Coil. In good used condition </p>

www.ebay.co.uk

John

 

[lostinthelight]

Ive converted dozens of old villiers and Briggs engines over the years with an ignition module like these or the ones with two wires,

Ignition Unit Replaces Points & Condenser fits many Small Two Stroke Engines | eBay

Ignition Unit, Replaces Points & Condenser.

www.ebay.co.uk

 

[Burnerman]

A new one on me......useful bit of kit!
It doesn't do away with the coil though, but fb may be interested in that.
John

 

[lostinthelight]

A new one on me......useful bit of kit!
It doesn't do away with the coil though, but fb may be interested in that.
John

They do rely on the old coil, you can remove the points or just cut the wire to them . Iirc they originated inAustralia
and came in plastic, blue or green to suit different engines, even supposed to have some sort of built in advance but I may have dreamed that one. They were so useful to get rid of the points on villiers engines fitted to machinery that wasnt used that often to guarantee a first time start

https://www.allotment-garden.org/rotavator-manuals/landmaster-100-manual.pdf

 

[forestboy]

Ive converted dozens of old villiers and Briggs engines over the years with an ignition module like these or the ones with two wires,

Ignition Unit Replaces Points & Condenser fits many Small Two Stroke Engines | eBay

Ignition Unit, Replaces Points & Condenser.

www.ebay.co.uk

Yes, interesting - but the coil appears to be defunct - so wouldn't be able to use it.

 

[forestboy]

I think i will see if I can remove the flywheel and see what condition it is underneath before I decide what to do. That no doubt will be a task in itself. There comes a point where, if it's not a hobby, you are throwing good money after bad.

 

[forestboy]

Is this the one?

briggs and stratton 2hp Ignition Coil | eBay

<p>briggs and stratton 2hp Ignition Coil. In good used condition </p>

www.ebay.co.uk

John

It looks similar but without a part number it's stab in the dark. Might be worth offered a tenner perhaps. Not sure how the seller reckons it's in good condition - there's no mention of any resistance testing.

 

[forestboy]

I have located the engine as part number 80302. Here is the parts diagram on the Briggs & Stratton website. I appear to need part 298502 (points and condenser) engine? Not the part 389593/591420. 50 quid new

 

[Burnerman]

Remove the flywheel first... there’s a good chance you won’t need new points.
Undo the flywheel nut, but don’t remove it. With a couple of wedges under the flywheel against the solid engine block, a sharp tap with a jammer on the flywheel nut should break it free from the tapered crankshaft.
John