OMC Orifice Plugs

**Xpress2830** · 12-14-2015

Hey guys I have a 93 Johnson 40 milled head to 150psi, ported 50 reed cages with Boyesen rees, 50 carbs ( plastic top 2 jet carbs). Hs jet is 55D ls is 45D. My plugs are stayin too wet and motor doent idle as good / crisp as it should. I did have 49D when I ran it last, also tried the 71D but it didn't idle good. My thoughts are I am getting too much air with the ported cages, bigger carbs and the ls 45D. Should I keep goin smaller on the ls air jets until I get the right mix? Any thoughts would be appreciated...

**oledawg** · 12-15-2015

Originally Posted by Xpress2830

Hey guys I have a 93 Johnson 40 milled head to 150psi, ported 50 reed cages with Boyesen rees, 50 carbs ( plastic top 2 jet carbs). Hs jet is 55D ls is 45D. My plugs are stayin too wet and motor doent idle as good / crisp as it should. I did have 49D when I ran it last, also tried the 71D but it didn't idle good. My thoughts are I am getting too much air with the ported cages, bigger carbs and the ls 45D. Should I keep goin smaller on the ls air jets until I get the right mix? Any thoughts would be appreciated...

Sounds like your too rich on the IS air jets. Try going to a larger IS to lean down mixture. The 71D's on HS are way too much. If I had to guess, I'd go 55-56 HS and 50-54's IS. How is throttle response off idle thru midrange?

**oledawg** · 12-15-2015

Also, the reeds can't give too much air. The air is controlled by the carb size. The improved reed flow merely allows what the carb has to offer to enter engine better. The fuel/air ratio is set by the carb bore and jet size before it enters reeds.

**Revengable** · 12-15-2015

Leaking float valves only messing with low demand ? It would take a lot of air to wet a plug.

**Xpress2830** · 12-16-2015

Yeah I tried the 71C and too much air. Dropped down to 49D a little better, now I have 45D idles better but still not as good and crisp as it should. Do you think I need to keep goin smaller until I get the correct mix? I am runnin 55D HS...Hey also I may need to run the C style orifice the fuel flow is reversed from the D...Your thoughts. Thanks, Bobby...