Spark Plugs

[Andrew_Fanner]

Tinkering with a friend's outboard on Sunday I had to clean a lot of fouling off the plugs. Given that a 35HP 2 stroke engine is overpowering a 20' Norman on the Thames the plugs were a "bit" oiled up! Changing the engine isn't really an option so might hotter plugs be a solution? I wondered about knocking the mix from 50:1 to about 65:1 but that sounds a bit chancy, especially if the river gets a bit of run in it and more power is suddenly needed. Changing plugs between "cruise" and "grunt" seems practicable.

What do the team think? Apart from live with it that is

<hr width=100% size=1>Two beers please, my friend is paying.

 

[Tekkie]

From our experience with large O/B's running slowly during Training Courses, I'd recommend moving up to "hotter" running plugs. Also found this works with some older 2 Stroke Bikes. Hope this helps.

sail safe

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[Aunt_Erika]

This may also help my 45hp 4stroke fitted to my viking 26,the engine runs at 2000 revs most of the time ,but how do i recognize `hotter plugs`?.The manual spec for plugs is NGK DPR6EA-9.

Please help ,Dave

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[toad]

From memory 6 is the heat range 9 is the gap,so 7 will be hotter 5 colder.

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[chippie]

Hotter plugs should reduce oiling at low speeds, but be careful if you later decide to run flat out.

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[andyball]

always found the ngk thin centre electrode plugs (used to be called v-type) very good for enduro bikes often pottered between flat-out blasts, not too pricey for a twin(?)- & almost oiling proof.

If by fouling you mean the hard deposits- try another (better) 2-stroke oil.

had many problems with failure due to oiling with champion/ND/Bosch plugs - ngk seemed much better, even in the normal ranges.

rich'ish fuel mixture will aggravate plug-failure on a 2-stroke much more than a bit too much oil/too cool a plug in my exp.


"v" ones (platinum) now replaced by "iridium" in ngk & ND <A target="_blank" HREF=http://www.sparkplugs.co.uk/pages/technical/iridium_spark_plugs.htm>here</A>
<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by andyball on 02/07/2004 10:52 (server time).</FONT></P>