L78V vs L76V

[krs60]

Is it ok to run the hotter L78V plug over the L76V plug on my 1977 mercury 850 85hp?

 

[CharlieB]

Re: L78V vs L76V

Not usually.

An aged worn motor with minimal compression may require a hotter plug to burn the plug cleaner at WOT, but normally, any motor in decent shape, NO.

The ONLY time I run a step hotter plug is when I am running extended time at low trolling speed with absolute minimal WOT, such as just long enough to get it up on plane then yanking the throttle back to minimum cruise speed.

Hotter plugs at WOT risk detonation which will cause serious piston/cyl damage.

 

[krs60]

Re: L78V vs L76V

Thanks for the reply. A few people (not from these forums) told me the L78V is better in my motor and the L76V is getting harder to find and is most likely going to be discontinued? I better think about getting the L76V plugs, i just hate having to order plugs and wait for them. Maybe i'll order 2X what i need.

 

[Gomer50]

Re: L78V vs L76V

I use the NGK BUHW plugs with good results and they are available at any auto parts store.

 

[krs60]

Re: L78V vs L76V

I found some L76V plugs before i found the NGK plugs. I do want to try the NGK plugs in the future.

 

[Chris1956]

Re: L78V vs L76V

The BUHW Plugs are direct replacements for the Champs L-76V. Autolite also makes a version. I would not worry about the Champs being discontinued as there are lots of motors using them and lots of replacements from other manufacturers.

 

[basstracker1970]

Re: L78V vs L76V

Are the BUHW-2 plugs ok to run ? What is the difference in them?