Boyer Ignition testing and what to expect

Have you measured the voltage at the Boyer box? It needs to be at least 12volts.

I'm always unsure about what constitutes a good spark. The modern BTH magnetos give what looks like a feeble spark but are said to be fine in use.

Having said that, a white sparkle doesn't sound that good. Will it burn through a piece of paper?

Ian you have not answered the statement by Dan, have you got 12V? Certainly a whitish spark is not much use, needs a decent blue thing. You can send the BB Amplifier back to BB for testing (or to me but BB will give a better test) the cost of a BB amplifier (MKIV) could be £60 while the cost of a decent magneto would be several hundreds, then there is the work fitting it, removal of ignition switch etc.-don't do it. But you do not state the year of the ES2. Is it a dynamo model fitted with electronic ignition (Bad move) or is it an alternator model-plenty of battery charging?

I wasn't suggesting Dan should fit a BT-H, just using it as a comparison as I had one of these recently and thought the spark looked a bit feeble. I was advised that although it didn't look wonderful it was very effective - although I didn't have the opportunity to try it in practice.

Previously jonathan_newton wrote:

Ihave aBB mk 3 on a ES2 recently purchased whichwill notstart. Valve timinggood, compressiongood, carb andfuel good, batterygood on optimate, ignitiontimingasgood asyou cansetstatically,butno sign ofstarting.Itstarted (afteralot offiddling) when Ibought it andtickedoverdecently butsince then it hasbeen absolutly dormant.

Ireadin theboyerdocumentsthatifyouswitchpower on/off it shouldspark at theplug which it does,butnot afatblue disharge, more of awhitesparkle ofshortduration. IsthatwhatI shouldexpect?

If Ikick it overwith the plug out thethesamefeeblesparke appears but I am in doubt as to thestrength ofittoactually ignitethemixture.

Ihaveadvanced it further toget atleast a missfire orkick backbutnojoy.

Are there anyothertricks or tipsIshouldbe looking for before I buy amagneto andbe donewith it!!!

Anyhelp appreciated....

Hi,

As mentioned, first check is a good 12V at the Boyer, although you say battery is good on Optimate so that should be OK.

Next, are you happy that you have a good plug / HT lead / suppressor cap / coil ? Can you swap in any known good bits?

Do you have or can you borrow a Gunson colourtune, this will enable you to see inside the combustion chamber as it fires. It is not unknown for a plug to fire out in free air but does not fire when under compression.

Tony