1961 Merc 400 - Spark Plug Gap

[lindy46]

Well, I finally got the cowl off and checking the plugs. It has Autolite 295 plugs in it - is that correct? What is the proper gap?

 

[emckelvy]

Re: 1961 Merc 400 - Spark Plug Gap

Autolite 295 is equivalent to a J8 which is too hot a plug unless you're idling all the time.

Autolite 354, NGK B6S, or Champion J6C would be the correct plug.

They are 3/8"-reach with the correct heat range and cut-back ground electrode for use in a 2-cycle engine.

Gap 'em around .030".

HTH.........ed

 

[lindy46]

Re: 1961 Merc 400 - Spark Plug Gap

Thanks Ed - I'll switch to the J6C's - got lots of them around. This engine runs very strong and really has a lot of power and speed on the little 14' Starcraft. At WOT it's running 5000-5500 rpm. Is that about normal?