I bought some cheap chinesium rebuild kits off of ebay a few months back due to carb related problems (not a bad kits for the most part). The pickup/emulsion brass tubes were clogged so I replaced them. But the cheap Chinese tubes were poorly machined (all openings on the tubes were ruff/jagged and different sizes) and put them in cause the old ones were too clogged to clean. They fixed the problems I was having, but created a new issue that is starting to annoy me.

Any ways, I have some new OEM rebuild kits coming in next week for My 1984 Mercury Blackmax 150 / WH-29 carbs. The kits come with 2 different sizes pickup/emulsion tubes 0.023 and 0.028? I believe 0.023 is stock.

Should I stick with stock size or put in the bigger sized tubes in?
If the larger tubes are put in, what would happen? IE... running rich/lean/flooding/more power/nothing

I had the same motor on a 1984 350v Ranger and I put a set of XR6 carbs on it. Worked great with the idle air adjustment. There is a chart showing stock sizes for everything on your carbs. Should be able to find in a search.

Don't know if boat motors are same as Motorcycle engines but the bigger hole(s)on emulsion tube gives a richer mixture at idle and just off idle thru midrange.

stock.....