Spark Plug Cap

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Trantm
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Spark Plug Cap

Hello all,

I was reading this discussion (below) as my MK5 has no spark suddenly:

https://www.oldlawnmowerclub.co.uk/forum/history-and-technical/technical...

I tested the coil with a volt meter and I was getting a reading of 3 set at 20k.  I think this is okay.  I have a feeling my spark plug cap is the issue.  Is this common or not?  It is the type of cap that screws into the HT lead.  Could I buy them from the normal Villiersparts or meetens or should I buy a new Magnetron coil with, what looks like, a different spark plug connector?  

Lastly the starter clutch on the MK5 are the bearings meant to be loose?

Thanks,

Mark

 

wristpin
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Most Briggs HT leads just

Most Briggs HT leads just have a metal clip to push over the plug terminal.  Some have a rubber cover over the clip. Take the plug out and hold the HT clip a quarter of an inch away from an unpainted metal surface and pull the starter rope. The spark should jump that gap. If it does that ok and the spark plug is correctly gapped at 30th” , you should be ok.

General rule of thumb is a plain unsuppressed plug cap is used with a resistor plug with an R in the number eg BR2LM. If someone has put a suppressed / resistor cap on the HT lead you can run with a plain , non resistor plug , B2LM.

Trantm
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I have seen the metal clip on

I have seen the metal clip on the HT leads that you refer to (when looking for a new coil) but mine doesn't have one on the end of the HT lead.  See a picture below, it is just a screw on the plug cap that screws into the HT lead.  My plug is not a resistor plug so do I have the wrong cap?

when I tested the coil I took a reading from the coil fixing to the hole in the HT lead.

Thanks,

 

 

wristpin
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Turn that bare lead round and

Turn that bare lead round and do the spark jump rest to that convenient bolt head. If it jumps a 1/4  -  5/16” gap your problem ie either the cap or the plug. 

Trantm
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No - no spark jumped.  So

No - no spark jumped.  So even though the volt meter gave an okay reading is the coil the issue?  Is there a correct gap setting between the coil and fly wheel/brass wheel?

If I need a new coil I assume auctions sites/meetens are best?  My MTC is below if you happen to know the part number.

80432

0586-01

77051603

 

Thanks again

wristpin
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Your model and Code numbers

Your model and Code numbers suggest that your ignition  would have been the original points and condenser system . So if it has not been updated to Magnetron your problem may be solved by just cleaning and adjusting the points. That will involve removing the flywheel but if you wish to avoid that operation , just leave it in place and fit an electronic coil - either a genuine Briggs Magnetron unit or a pattern one.

Trantm
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Thanks - I will try to remove

Thanks - I will try to remove the flywheel.  There are some American youtube demos but they use a bit of force!  You guys on this website should record youtube clips of servicing and re-builds.  

Meetens wanted £249 + VAT for a new electric coil?!!  can you advise of the part number as on auction sites for £30

 

Trantm
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Oh lastly - if I bought a new

I got lucky and flywheel was okay to remove:  points look clean.  Do you suggest cleaning points with paper once they are closed etc?

 

 

Thanks

 

wristpin
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Remove any corrosion with

Remove any corrosion with fine wet or dry , set the 20 thou gap and the close them on a bit of clean copy paper. Pull it through the closed points but don’t let them snap shut on the edge of the paper and trap fibres.

Actually looks nice and clean in there but always worth checking that the plunger is moving freely . The braided strap on the moving point is incorrectly routed but doesn’t look in harms way.

wristpin
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Meetens wanted £249 + VAT for a new electric coil?!!  can you advise of the part number as on auction sites for £30

How odd, the original part number for a points system was 397316 which changed to 592420 for the Magnetron electronic one.

Full retail price with vat  £42.30. You can probably pick up a Chinese one for less than £20 but the quality is variable.