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Ngk gap

R

RANMAN

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I have a 2019 Mercury 60HP 4 stroke ELPT. The manual calls for the Champion RA8HC plugs and a gap of .040. I'm not a big fan of Champion, but decided I'll go with them. When I gap plugs I like the ground electrode to be straight across the post electrode. I was able to do this with 2 of the plugs, but the other 2, the best I could do was have the ground electrode going up at a angle over the electrode post. Checking out why, I found the latter 2 plugs had an electrode post about .008 longer then the first two. I'm even more against Champion plugs now. SO, to my question. I'm going to go with NGK plugs and the cross reference number is DCPR7E, but I can't find a definitive gap spec. I found a link in this website that gave .028, but that sounds too tight. Does anyone have a gap that works for them with this plug and engine?
 
I have the same motor. The service manual and the label on the flywheel cover specify a gap of .040. My original plugs had that gap. New plugs have a .025 gap. I bought the parts from Mercury. The post is clearly longer in the new plugs, reducing the gap. I regapped the plugs to .040. The ground post is not quite parallel after regapping. Seems to run fine with new plugs. I’ve read of a similar issue with Harley Davidson motorcycles that people use the same plugs as substitutes for the Harley plugs. The Harley plugs come with .040 gap. I wonder if Harley plugs would be appropriate for this outbiard.
 
Your guess is as good as mine. The problem is that I have to be careful of what I do, because my engine is still under warranty.
 
I checked the plug numbering system, but the number I previously indicated didn't have the gap as part of the number. It stated separately the gap is .028", which like I previously stated seems too tight. Other places, on the internet, I found a site indicating .031"-.035". Probably what I'll do is set the gap at .040" and see how it runs. If its giving a problem I'll knock the gap back down too .035" and take it from there.
 
Mercury uses an unloaded 40kv ignition system to burn through possible contaminants on the insulators and corrosion on the electrodes. To get the benefit you need a wide gap. 0.040 is the gap my Mercs use as specified in the serv. man.
 
Texasmark said:
Mercury uses an unloaded 40kv ignition system to burn through possible contaminants on the insulators and corrosion on the electrodes. To get the benefit you need a wide gap. 0.040 is the gap my Mercs use as specified in the serv. man.
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0.040 is what I'm going to go with. Thanks
 
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