1973 Johnson 25hp Spark Plug

[nytebyte]

What spark plug should I run in this 73 25hp? The UJ4J Is hard to find and was thinking a J4J or J6J would be fine, I would just as soon stay with Champion brand.

 

[racerone]

Try NGK---B7S

 

[nytebyte]

Will do as I always value your opinion

 

[vics]

The recommended plugs are Champion J4C

.

 

[faztbullet]

Autolite 353 works real good

 

[kevinj]

Marineengine Champion Plug Chart

 

[nytebyte]

I have seen charts that recommend both J4c and J8c so we do have a few out there. Saw one place that said this is one of the few motors that even Johnson recommended the NGK B7S as it supposedly did better than Champion