plug gap

[dreamchaser]

1979 ob merc 7.5, My manual says to use surface gap plugs. Went to the dealer to buy new ones, they gave L77jc4 normal type plugs with the gap. Theres no spec in my manual for the gap . Anyone know the correct gap ? thks........

 

[rdgordon1@cox.net]

Re: plug gap

This may be way off base but the first thing that comes to mind here is clearance.If your engine uses surface gap plugs is there enough clearance for the piston at TDC to clear the electrodes on an conventional plug without interference?I would want to know that for sure before I worried about a plug gap.You can get the wrong parts guy at the counter and an innocent mistake can get expensive very quickly.Not to alarm you but the flag went up when I read that.Ron G

 

[diaric]

Re: plug gap

looked on a champion site. upto 78 used surface gap. 79 and up is a modified gap(normal style). site may be wrong, or year may be incorrect. some double checking is in order