Mercruiser 350 carb

[wryork25]

Good morning all,
I need some help, I have a mercruiser 350 2 barrel carb engine. I attempted to rebuild the carb because it was dumping fuel at idle. The boat ran really rough, before I when I initially found the fuel dumping. Fast forward, now the boat has a tough time starting and is backfiring like crazy. I am scared I am going to damage something due to the amount of backfiring. I am not really sure what to do from here, I have not given up as I am trying to avoid the mechanics bill. Any suggestions on what to do next would be greatly appreciated.

 

[Bondo]

Good morning all,
I need some help, I have a mercruiser 350 2 barrel carb engine. I attempted to rebuild the carb because it was dumping fuel at idle. The boat ran really rough, before I when I initially found the fuel dumping. Fast forward, now the boat has a tough time starting and is backfiring like crazy. I am scared I am going to damage something due to the amount of backfiring. I am not really sure what to do from here, I have not given up as I am trying to avoid the mechanics bill. Any suggestions on what to do next would be greatly appreciated.

Ayuh,..... Backfires are usually from a lean condition, so go back, 'n attempt the rebuild again, fixing whatever ya screwed up the 1st time,.....

 

[cyclops222]

Did you adjust the idle mixture screw ? Did you also adjust the fuel pump squirter screw ? Or the linkage holes ? Did you also adjust the idle speed screw ? Did you adjust the Distributor timing position ?
Did you change the piston that moves up and down ? Did you keep the piston flexible part NEATLY INSIDE of where it slides up and down ? Did you replace the sparkplugs ? Check the gap and adjust if necessary ? Did you have to adjust the float level with the gauge supplied ?
What company did you buy the parts from ?

 

[Bt Doctur]

new 2 barrel on ebay, 135 work just fine

 

[bajaman123]

What did your "rebuild" consist of? Because some people do it right and disassemble the carb, ultrasonic clean or ChemTool clean everything, clean out all the jets and various orifices, etc. Some people will just put a new float, needle, and seat in and think they "rebuilt" it. Assuming you did it the correct way, one hopes that you counted the number of turns on all the screw-ins as you took them out, and then bottomed them out and opened them up that same number? If not, what carb is it? Holley? Weber? Tons of information out there to set those things at a good starting point. As noted above, you are almost assuredly running way too lean...and that's a simple fix...either you don't have the fuel jets set right and/or you have an air leak at a gasket.

 

[wryork25]

Did you adjust the idle mixture screw ? Did you also adjust the fuel pump squirter screw ? Or the linkage holes ? Did you also adjust the idle speed screw ? Did you adjust the Distributor timing position ?
Did you change the piston that moves up and down ? Did you keep the piston flexible part NEATLY INSIDE of where it slides up and down ? Did you replace the sparkplugs ? Check the gap and adjust if necessary ? Did you have to adjust the float level with the gauge supplied ?
What company did you buy the parts from ?

Yes to all your quesrions, I purchased my rebuild kit from Mikes Carbs on the net

 

[wryork25]

What did your "rebuild" consist of? Because some people do it right and disassemble the carb, ultrasonic clean or ChemTool clean everything, clean out all the jets and various orifices, etc. Some people will just put a new float, needle, and seat in and think they "rebuilt" it. Assuming you did it the correct way, one hopes that you counted the number of turns on all the screw-ins as you took them out, and then bottomed them out and opened them up that same number? If not, what carb is it? Holley? Weber? Tons of information out there to set those things at a good starting point. As noted above, you are almost assuredly running way too lean...and that's a simple fix...either you don't have the fuel jets set right and/or you have an air leak at a gasket.

It is a 2 barrel mercarb, yes I took it fully apart except for the choke housing. I could not get the housing screws out so I left that alone. I took the choke spring off and let the rest. Soaked, cleaned, blew it all out, and put back together. I am going to soak it again, maybe a passage was still clogged. I got it off and apart the only gasket that didn't make it was the center screw on the ventura, any idea if I can get a washer like that at the automotive store

 

[wryork25]

So I took it back off and I am going to soak it again. I do have a question, the sealing washer under the center screw of the Ventura does not seem to have made it. Does anyone know if I can get a washer like this from the auto parts store.