It was a Rebuild, with an "update" to an Electric Choke.There are lots of rebuilds out there. I believe the one jimmbo posted is a rebuild. The only “new” replacement I have found for the Rochester carbs for the 140s is the Sierra 18-7370n.
If the Throttle Shafts are loose, and letting Air in, causing problem getting Consistent Idle, then the Carb is pretty much a Paper Weight. Corrosion on the Power Valve should be removable, with a bit of Polishing.I tore it apart there was corrosion on needle valves and power valve. kits dont have needle valves carb is 1351-5203A1 linkages and casting sleeves are worn and I can't get repeatability on idle. just wondering if there a sub for a $365+ rebuilt that will be a little less money and give me better performance.
It looks like this is the problem. I have purchased the i5Carb refurb I m hoping they are quality we"ll know soon. if not I'm going to go the route of adapter plate but I'm sure there are a lot of adjustments once you walk. away from OEM specs.If the Throttle Shafts are loose, and letting Air in, causing problem getting Consistent Idle, then the Carb is pretty much a Paper Weight. Corrosion on the Power Valve should be removable, with a bit of Polishing.
Every Carb Kit I have ever seen, included a Needle and Seat, for the Float Inlet. If you are referring to the Idle Mixture Screws, they only need replacing when someone insisted on overtighten them, instead of Lightly Seating them. Rebuilding a Carb includes careful Examination and Adjustment of Linkages to compensate for Wear
the ones on amazon are 3 3/4X2 mine is like your 3 1/4 x 2 and I out checked the one I purchased from Marine carburetor and realized it is the wrong one its the same as amazon *!#& oh well back to the search!You have identified two different base bolt pattern sizes. I was not aware of that. The Rochester on my 1974 140 has a 1 7/8” x 3 1/4“ bolt pattern, which I understand to be the “small” base. I don’t see the Sierra 18-7370n bolt pattern described anywhere. Do you know what it is? What is your bolt pattern?
tone of these will adapt your small base manifold to large base carbs..... I went down this route earlier this year with my carb.... the small base units are unobtanium in marine trim new, everyone uses the large base carbs....
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I will be interested to hear how that carb works for you.I got ahold of Marine Carburetor today they shipped me a rebuilt with the small base apparently they have both. very courteous and great to deal with we'll se hoew it runs in a couple of days.