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Hi guys, a quick question.

2003 Johnson 90hp 2 stroke

By mistake I got an 8 pack of Champion QL87YC plugs versus QL78YC.
The higher 87 number is a hotter plug.

Everything else about the plug is identical.

Is it a problem to run these hotter plugs? I'd obviously like to use them if possible, but don't want to do any damage.

I was wondering if these hotter plugs could affect the lubrication in the cylinders or not enough to matter.

Best regards,
Doug

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2003 Four Winns 170 Freedom Cincinnati, Ohio / Cape Coral, Florida

Trying to research this answer, I found mixed results.
When I called a local Johnson mechanic, his answer was simply to use what the manual called for.
I finally got a hold of Evenrude Tech support and they said these 87's may be a little to hot for my engine and could cause premature firing.

Now I have an 8 pack of the 78's on order. Better to waste $25 worth of plugs than to do some damage.

I wish they would have been ok for a limited period of time

FYI,
Doug

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2003 Four Winns 170 Freedom Cincinnati, Ohio / Cape Coral, Florida

I would not use them. Hotter plug can easily lead to pre detonation which will burn a hole in the top of the piston. I have seen this before.

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The Dance II
2007 278 Vista
6.2L Mercruiser

Thanks Goldfish,

I already ordered the correct ones and I'll try to give these away.

Not worth $25 to damage the engine.

Best regards,
Doug

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2003 Four Winns 170 Freedom Cincinnati, Ohio / Cape Coral, Florida

You made the right decision, hotter plugs in a 2 stroke could be a bad thing, especially if the fuel mix was a bit on the lean side. They usually have too hot combustion chamber issues, not too cold.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II