Fuel Jets or Air Jets in my carbs....

[BKS72]

My Boyesen reeds just came in and the instructions tell me which jets to replace and with what sizes, but I'm confused on which type of jets I have in my carbs.

They list 2 options in the instructions, one for carbs with "idle air jets" controlling idle and one for carbs with "low speed fuel jets" controlling idle. I'm assuming that what they call "low speed fuel jets" are the off-idle jets in my carbs and the ones I need to replace, but I'm not sure. Dumb question, but not as dumb as not asking and screwing up $70 worth of parts

It's a 1980 75hp E75ERLCSA and I have idle, off-idle, and high speed jets currently in the carbs, P/Ns:

325837 (idle, top and bottom carbs), 325836 (idle, middle carb)

323703 (off-idle, all carbs)

320921 (high speed, all carbs)

Thanks!

Branden

 

[Dhadley]

Re: Fuel Jets or Air Jets in my carbs....

If your idle jets are exposed to air, they meter air and are idle air jets. If they are behind a screw and are not exposed to air, they meter fuel and are fuel jets.

If you have the original carbs I believe the idle jets are fuel jets. To go richer on fuel jets you go to a bigger number.

 

[BKS72]

Re: Fuel Jets or Air Jets in my carbs....

Gotcha - mine are under screws, so they must be fuel jets. Low speed jets they're saying to change are my off-idle jets as the OEM manual calls them or should I change the idle jets? Thanks!

 

[Dhadley]

Re: Fuel Jets or Air Jets in my carbs....

All the jet changing is to cover themselves for warranty. If your motor doesn't spit back thru the carbs at idle then you'll be fine. But if there's any doubt in your mind then by all means go richer. I'd go a couple numbers richer on the idle circuit. Not really sure why they want you to go richer on the mid range. If you do go richer it can't really hurt anything by going a couple numbers richer.