# 18 HP B&S V Twin no spark HELP!!!!



## earnies2 (Feb 8, 2009)

18 HP B&S V Twin no spark....isolated engine from truck still no spark...removed ground wire from coil no spark removed cover unpluged coil no spark..... bought new coil ran for 10 minuets than stalled started up ran but stalled under load tried several times kept stalling...than no start... brought back to shop tested like before removed cover unpluged coil no spark thought i might have bought a defective coil so i bought another one still no spark...fly wheel has great magnetic pull I'M lost.....any help would be appreciated .......:4-dontkno


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## MrChooks (Apr 19, 2008)

:wave: Hi & welcome to TSF.

Aaaaahh!!!!  - transient electrical faults in ignitions are a real PiA :upset:

Assuming you have replaced the electronic ignition / coil assembly and the problem is still there - it must be a connection problem somewhere - either a short, or a failure of the circuit to complete.

Temporarily take all the kill wires / low oil protect circuit wires out of the system - see if that solves the problem. If not, then remove the ignition / coil assembly and thorough clean the mating surfaces of both (use some fine emery paper to sand off any surface corrosion / muck) so you have a clean metal to metal mate, between the engine block and the ignition parts.

Whilst you are in there (messing with the ignition) - take the opportunity to carefully check every electrical lead and connection

Lastly - it won't be the magnets in the flywheel - even when they are very weak - they still work OK - so it has to be something in your electrical / ignition circuit/s:sigh:

Hope this helps


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## earnies2 (Feb 8, 2009)

I belive i have isolated all electrical functions by unpluging the black wire on the coil.....i even chainged out the coil with another new one ....i will take it apart again and clean the mounting surface for the coil and try it again....and will report back.....I beleive the gap is 10-14 is that correct....How does the gap affect the spark? does it affect the streingth or the timing?.....I will go to the shop tonight and do that I'll be back.....THANKS:wave:


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## MrChooks (Apr 19, 2008)

Hi Earnies2 - Not sure of the gap (presume you mean between the flywheel and the coil) - should be in your owners manual if it is adjustable, or check the B&S site below:

http://www.briggsandstratton.com/maint_repair/manual_and_more/

Just one other thing - and don't throw rocks at me for asking this :4-surrend - but just check you have the ignition / coil assembly mounted on the correct way out - I have a feeling that on some of the B&S twins you can "inadvertently" mount the coil assembly the wrong way round and that messes up the ignition big time.:sigh:


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## earnies2 (Feb 8, 2009)

(Just one other thing - and don't throw rocks at me for asking this) I would never throw rocks........that was a valid question and you can mount the magnitron backwards....it acually looks correct with the ground plug on the front and the spark plug wires out the back...but if you read the note on the unit it states cyl side and this side out........its mounted correct...I checked the manual and the gap is .008-.012 I have it at .010 It should work but it dosent want to cooperate.....I am baffled tomorrow i will replace the mag with another new one and see what happens....any other susjestions short of throwing rocks at it let me know i'm all ears.........:4-dontkno


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## MrChooks (Apr 19, 2008)

:wave: Tks Earnies2 (I hate having to duck from flying rocks!!!:sigh

If you have a good connection / circuit and the unit is OK - the damned thing simply MUST work!!:upset:

So if you are happy that you have a good ground to the frame, all the kill wires are disconnected and it still doesn't work - I agree with you - the unit is a "dud" :sigh:

In my experience, that is rare - but doesn't mean it can't happen - for all we know, maybe B&S has a batch of dud units out in the market - and they would be the last people to tell anyone, if that were the case!!!!


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