Fuel lines to carbs 50esl74m Johnson

[Keyboardman]

Hi guys, I finally found the factory service manual for my 74 50hp Johnson. According to the manual, the fuel line from the pump should go to the top carb and then the bottom one. On my engine, the fuel line goes to the bottom carb first then up to the top carb. Looks like I'd need to change the float bowls around to make it like the original configuration. I'm still working on a slight miss/sneeze with this engine. Could the fuel line situation be part of the cause??

 

[gm280]

Could be if you look at it from a physical stand point. While there is fuel pressure, obviously, I would certainly make the fuel line corrections before trying other things to verify you actually have a problem. Servicing the top carb first with fuel from the fuel pump and then the lower one could fix all that miss/sneezing. I don't know your engine set up, but some times the top carb is jetted differently then the lower one(s). So try if first and post back with your lastest results. :thumb:

 

[emdsapmgr]

You may want to view the original parts catalog from 1974. Check out this website: epc.brp.com You will find various fuel hoses on the fuel pump diagram as well as the intake manifold diagram. The intake diagram shows a connector hose between the upper and lower carb. Since I don't see a "tee" anywhere, the upper carb may have two hose barbs, one for incoming fuel from the pump, and a secondary connector to the bottom carb. You will know more when you compare your setup with the diagram. We don't have the ability to visually see the port side of the carb bodies.