Which water fuel separator for 1990 9 0 hp johnson....10 or 25 micron?

[Bassnwhaler]

Seems my motor didn't originally have a water fuel separator so I cant find the original part to replace. I have a filter on now that is a mercury/ universal 10 micron. The motor is new to me and I am doing some basic maintenance. Do I stick with a 10 micron or go with the Evinrude version that is 25 micron? Thanks

 

[dingbat]

Seems my motor didn't originally have a water fuel separator so I cant find the original part to replace. I have a filter on now that is a mercury/ universal 10 micron. The motor is new to me and I am doing some basic maintenance. Do I stick with a 10 micron or go with the Evinrude version that is 25 micron? Thanks

Merc and Evinrude filter mounts are not interchangeable. The Mercury filter have 11/16"-16 threads, Evinrude has 1"-12 threads.

All the major outboard manufacturer recommend the use of a 10 micron filter. Some (Yamaha) go even further and recommend the use of a 5 micron filter.

As for brand, I use nothing but Racor filters. Far better performance specification than the big box alternatives.

 

[Bassnwhaler]

Thanks! Currently this one is on my Johnson. Confusing.

 

[Bassnwhaler]

[No message]

 

[dingbat]

Thanks! Currently this one is on my Johnson. Confusing.

Not really. Most aftermarket filter heads adapted the Mercury 11/16-16 thread size. The filter heads using the Johnson/Evinrude 1”-12 threads are OEM.

Racor OEM filter heads use a different thread size yet but make filters to fit Merc and J/E OEM filter heads