OMC Jets

[PaulO]

Been fooling around with multiple sets of carbs for so long that I lost track of which ones have which main jets. I'm talking 1999 225 with the big carbs that have the recessed hex head idle adjustment screws. Something in my memory says something about a different larger main jet for one cylinder (#2?). Is that the case? If anyone knows what jets are correct, I would really appreciate that info. Thanks.

[keefallan]

goto Marine Engine.com and look up your motor. They will tell you what jets you have

[perfmarine1]

5 and 6

[Instigator]

Depends on yr and model.

Most do not have staggered jets.

epcbrp.com will tell you too.

[PaulO]

I have 72s and the parts sources say different things including 76s. Anybody know which is correct?

[Instigator]

Probably 72’s in 225’s and 76’s in 250’s and 225 HO’s which are the same motor.

The one I posted is BRP/OMC and the only one I’d trust.

Be aware, they may list ten different 225’s and five different jetting specs.
A well tuned two Stroke is VERY sensitive to jetting.
Couple steps the wrong way and you’ll be rewarded w/a glowing ingot!

[PaulO]

Probably 72’s in 225’s and 76’s in 250’s and 225 HO’s which are the same motor.

The one I posted is BRP/OMC and the only one I’d trust.

Be aware, they may list ten different 225’s and five different jetting specs.
A well tuned two Stroke is VERY sensitive to jetting.
Couple steps the wrong way and you’ll be rewarded w/a glowing ingot!

I assume better to err on the side of too rich?

[Instigator]

Correct

I assume better to err on the side of too rich?

[MrG]

If you have the silencer in cowl 75 are great if you have that removed from cowl 78s are what I used (1999 225 ocean pro) if you have the one carb cover with two screw on front and drill 1 1/4 holes in cover at carb centers 85s are what I ended up with with baffles removed from cover ends some say why not remove cover comp well I don’t lie the oil and gas dripping out of carbs when sitting tilted and having to clean up so the recirc hose takes care of it no mess 22ft ollshore26 bravo one 70 mph fishing boat hope that helps took along time running and reading plugs also you have to open up carb seats for fuel flow cross flow seats are what I used https://youtu.be/Hlyxok6634k

[PaulO]

If you have the silencer in cowl 75 are great if you have that removed from cowl 78s are what I used (1999 225 ocean pro) if you have the one carb cover with two screw on front and drill 1 1/4 holes in cover at carb centers 85s are what I ended up with with baffles removed from cover ends some say why not remove cover comp well I don’t lie the oil and gas dripping out of carbs when sitting tilted and having to clean up so the recirc hose takes care of it no mess 22ft ollshore26 bravo one 70 mph fishing boat hope that helps took along time running and reading plugs also you have to open up carb seats for fuel flow cross flow seats are what I used https://youtu.be/Hlyxok6634k

thank you mr g. Got 76s on the way. Will try them and see.