Ignition coil on 8HP Model 19 type 1126 Briggs and Stratton

You cannot test a coil with a multimeter, you need a coil tester.

From what you have posted, I take it that you now have no spark, but the interesting thing is that you say there is a wire going to the governor. It is interesting because there is no connection between the governor and the ignition, do you mean that there is a wire going to throttle lever area, or is there a wire disappearing inside the engine. If it is the later, it sounds like you have oil-alert fitted, this shorts out the ignition if there isn't enough oil in the engine.

How old is the engine, is it old enough to have points or does it have electronic ignition ? The coils on both were fairly bulletproof and usually didn't just fail, they usually gave some sign of failure first, misfiring etc.

Check all the wiring again, if it is electronic ignition, you should get a spark if all thin wires going to the coil are disconnected, if this is the case, it must be the stop wiring that is at fault.

All seems a bit odd. Certainly no cunning over speed device just a plain old bit of wire! As for the coil kill terminal having continuity with the coil body - the metal armature that the coil is wound around? - definitely should not be so.

You mention first pull starting - has it also an electric starter? If it has I would be suspicious of a faulty key switch letting a dose of volts through the coil via the kill wire - quickest way to kill a coil known to man. If it has electric start before fitting your new coil connect a meter set to volts  between  the kill terminal on the key switch and ground and do repeated on and offs and see if on just one occasion you get a reading. I seem to remember a manual suggesting 50 applications of the key as a safe test!

Wouldn't worry about the length of the HT lead, it's for various different applications, but if it offends you there's no harm in shortening it other than the hassle of prising off the plug connector and doing a decent job of refitting it.

The  full model type and code would be useful.

Hello all,

To be honest, I haven't checked for a spark (I don't have the right plug socket to get the plug out). The details of the engine are:

model number 195432
type 1126 01
code 9211910

It doesn't have a pull-start, I'd guess that the engine was mid 90s, but can't be more accurate I'm afraid. The low-voltage wire runs in series from the kill-switch, to the terminal on the coil / solid-state ignition unit and then on to a terminal on the mechanical speed governor. There is clear continuity between the terminal on the coil and the metal laminates that are then bolted directly to some bosses on the cylinder head.

So, I think from what's been said, the coil has failed - which does seem surprising as they appear bullet-proof - so I'll order a spare. But it would be nice to understand what the connection between the coil and the governor does.

Thanks again for the help.

Cheers

.

Think that I'm loosing the plot here! In your first post you say "started first pull" but now you say "doesn't have a pull start"

Your Code shows that the engine was made in 1992, 11th month and day 91 ! could you have reversed those last two digits?  - 19th day of November 1992.

The coil does not connect to the governor . the kill wire may just fix onto an insulated terminal on the throttle plate and uses that termination to connect to the machine's on/off switch.

Before you blow £40 on a new coil, make sure that the oil level is up to the mark, disconnect the kill wire from the coil**,  take the plug out, switch to on, hold the plug lead with the metal plug connector about quarter of an inch from some un-painted metal on the cylinder head and rotate the engine briskly by what ever means is provided!  Hopefully you may see a spark.  If not, new coil it is.

** The model and type numbers suggest that your engine may be fitted with  an oil guard system so it is important to eliminate it by checking for a spark with NO auxiliary wiring connected to the coil.

Also the numbers suggest that that engine can be fitted with either an electric or recoil (pull)  starter  - or even both.

Without knowing it, you have posted the age of your engine, the third number tells you that, it was made on the 9th november 1992 and as such it will have electronic ignition.

The stop wire (what you are calling the low-voltage wire) should earth out through kill switch when the switch is turned off, the wire going to the terminal on what you are calling the mechanical speed governor is probably going to the stop switch on the external throttle mechanism, the governor is internal to the engine.

What Wristpin is saying about the stop switch destroying the coil is very much to be believed, if the switch is faulty and you fit a new coil without replacing the switch, then you will undoubtably destroy your new coil!!

This will only be a problem if the engine is electric start and 12V is going to what you are calling the kill-switch, if there is a fault in the switch, 12v goes down the stop wire and destroys the coil.

What you should be checking is all the safety switches ( I am certain that there will be safety switches) , if one of these has failed, then this could be your problem, to test this, disconnect any wires going to the ignition coil and then see if you have a spark, if there is a spark then the coil is ok and the problem is external to the coil, if there is no spark, then it does sound like the coil has failed, but you need to be sure that nothing external has destroyed the coil before fitting a new one.

Safety switches - good point!

does your machine have a removable inlet or ejector chute and have you had to remove either to clear a blockage? When correctly positioned they will almost certainly be holding a safety switch in the "safe" position but you may not have repositioned the chute precisely . 

However, with the kill wire disconnected from the coil all safety systems will be disabled so a spark test in that condition will be a true test of coil condition unaffected by external factors.

Hello,

Thanks for ll your comments so far - now I know it was built in November 1992 which is great -I thought it'd me about mid 90s, but its nice to tie it down. I was a bit tired when I wrote my last post and meant to say that it doesn't have an electric start, sorry for the confusion.

I don't think there are any safety switches, but I'll check tomorrow. Certainly there are no other wires going to the terminal on the throttle plate or the one on the coil itself. I already ordered a new coil, which arrived today - the annoying thing is that a quick check with the multimeter shows the terminal for the kill-switch is connected to the coil laminates - which I find odd as surely that means its grounded all the time? Anyway, I'll look for safety switches and try and test for a spark tomorrow, or over the weekend.

Thanks again for the hep - much appreciated.

Well, at least that means that the existing coil will not have been " blown"  by an unwanted injection of battery voltage. Hope that you haven't wasted your cash on an unnecessary new coil but it won't surprise me if with nothing connected to the coil you have a healthy spark.

So, it turns out that the culprit was the spark-plug. I swapped that out and it fired on the first hint of a pull - bit of adjustment needed to the mixture as I'd been fiddling with that to try to get it to start - but other than that it was straight back to business.

Thanks everyone for the help and advice.

Cheers