J-Tubes? How do I know I have a marine carb?

[cheburashka]

I'm looking at two Rochester two-barrels that fit my Merc 140. One has the Mercruiser tag on it. Internally they seem identical. The only difference I see is that one has a small tube coming up out of the side wall of the main opening at an angle, ending flush with the flange that the flame arrestor attaches to, and the other has a hole in the side of the intake with no tube sticking out.

Was there originally a tube in the carb that just has a hole? Shoud these be "j-tubes" that direct the flow down the cab throat?

 

[rodbolt]

Re: J-Tubes? How do I know I have a marine carb?

the 2bbl rochester does not need J tubes as the bowl vents inside the venturi area and if they flood it goes mostly in the carb. the holly carbs vent external of the venturi and requires J tubes to direct fuel into the venturi and not all over the engine in case of flooding or fuel bowl venting.

 

[cheburashka]

Re: J-Tubes? How do I know I have a marine carb?

That's good news. Now I'm a bit concerned about the carb with no tube coming out of the side wall. It's a 17059052. Was there originally a tube that went up into the intake area?

Thanks

 

[rodbolt]

Re: J-Tubes? How do I know I have a marine carb?

beats me.
most did.

 

[whywhyzed]

Re: J-Tubes? How do I know I have a marine carb?

some had the glass bowl to collect fuel pump leakage instead of the clear hose
edit- never mind me - I thought you were talking about something else obviously...

 

[Reel Poor]

Re: J-Tubes? How do I know I have a marine carb?

[qb] Was there originally a tube in the carb that just has a hole? [/qb]

Should have had a tube.

That is a MCM carburetor #.

Engine Model - MCM 140 / 3.0L / 3.0LX (4 cyl)
Serial # 5157669-6229717
Mercruiser Carb. # 1351-7355A1
Mfg. Carb. # 17059052