Resistor plug cap with resistor spark plugs????
Thread Starter
Joined: Dec 2001
Posts: 781
Likes: 2
From: UK.
Resistor plug cap with resistor spark plugs????
Hi hope you guys dont mind me using your forum but here goes, I am the owner of a microlight with a rotax 503 twin spark plug engine, of late its been loosing about 500rpm on full power after about 2mins of running at max power, checking the engine over today I noticed it has resistor spark plugs and also its fitted with resistor spark plug caps 5K ohm, could any of you guys advise if this is correct, I would have thought one or the other should have resistors in the them, me thinking it may weaken the spark them both being the resistor type, I should add I have only owned this aircraft a few months.
Regards Nick.
Regards Nick.
Joined: Mar 2005
Posts: 731
Likes: 0
From: England
If you're using NGK's for example
NGK BR 8ES are resistor plugs - no cap needed.
NGK BP 8ES are longer electrodes for inverted positions to prevent fouling.
NGK B 8ES - standard plug no resistor
If you have resistor plugs you shouldn't have a cap - double resistance/weaker spark.
Could just be a mix up last time the plugs were changed (part numbers similar) or there could be a genuine reason for this set up. I'd suggest getting in touch with whoever serviced it last and find out.
Fargoo.
NGK BR 8ES are resistor plugs - no cap needed.
NGK BP 8ES are longer electrodes for inverted positions to prevent fouling.
NGK B 8ES - standard plug no resistor
If you have resistor plugs you shouldn't have a cap - double resistance/weaker spark.
Could just be a mix up last time the plugs were changed (part numbers similar) or there could be a genuine reason for this set up. I'd suggest getting in touch with whoever serviced it last and find out.
Fargoo.
