1983 Johnson 175hp

[Whitman026]

Ok, the other day I went out and fired my boat up ran great, Yesterday I go out and fire it up and it don't want to start. I pulled the spark plugs and saw that they are the flat face UL77V plug, I knew absolutely nothing about them so I did some research on them. After reading about them they are ment for high RPMs for long periods of time but are not good for idle RPMs. My question is, is there a cross reference J hook spark plug? I believe the reason for my boat not firing is due to my old plugs being fouled.

 

[jimmbo]

QL77 JC4 is the latest recommended gap type plug, gap at 0.030". Myself I like the surface gap plugs for all uses. When they were introduced in the late 60s, they were touted as being foul-proof. My inline 6 still had the factory surface gaps in it when I traded it after 14 yrs of lots of use

My 98 150 Ficht must have used 15 sets of plugs(they weren't surface gap) the 5 seasons I ran it