No fuel to carb 4.3LX Mercruiser

[rodgeml1]

Engine: 1996 4.3LX Mercruiser

Issue: After running like a champ on Monday, I tried to start the boat on Wednesday and couldn't get it to start. The problem is clearly that I'm not getting any fuel to the carb. I pulled the fuel pump and put 12V to with the intake end in a cup of water and it pumps like a champ. I tried jumping 12V directly to the pump with it installed and the tube disconnected from the carb and still didn't get any fuel coming out. I verified that I can blow air through the tube from the tank to the fuel/water seperator, the tube from the fuel/water seperator and pump, and tube from the pump to the carb....all clear. I also tried cranking it with the fill cap off to make sure there wasn't a vacuum being pulled....still no fuel. The engine fires like a champ when I pour fuel down into the carb.

Any ideas on how to continue to troubleshoot the fuel problem?

Thanks in advance.

 

[Bondo]

Re: No fuel to carb 4.3LX Mercruiser

Engine: 1996 4.3LX Mercruiser

Issue: After running like a champ on Monday, I tried to start the boat on Wednesday and couldn't get it to start. The problem is clearly that I'm not getting any fuel to the carb. I pulled the fuel pump and put 12V to with the intake end in a cup of water and it pumps like a champ. I tried jumping 12V directly to the pump with it installed and the tube disconnected from the carb and still didn't get any fuel coming out. I verified that I can blow air through the tube from the tank to the fuel/water seperator, the tube from the fuel/water seperator and pump, and tube from the pump to the carb....all clear. I also tried cranking it with the fill cap off to make sure there wasn't a vacuum being pulled....still no fuel. The engine fires like a champ when I pour fuel down into the carb.

Any ideas on how to continue to troubleshoot the fuel problem?

Thanks in advance.

Ayuh,.... You pumped Water through the fuel pump,..?? :facepalm:

From yer description,... You've got a vacuum leak, Somewhere...

 

[2kjs]

Re: No fuel to carb 4.3LX Mercruiser

Check the fuel pickup tube inside the tank or try running off of a temporary fuel supply. I just went through this same issue, couldnt get fuel to carb but could blow through line back into tank,good fuel pump, etc.. switched line over to other tank (easy since have twins) fired up instantly. The problem as Bond-o stated was a vacume leak inside the tank. The aluminum downpipe going into the tank was was cracked just below the brass fitting so bad infact that as i was removeing from tank it broke off completely luckily i caught it before it fell into tank, replaced with a new plastic version and have had zero problems since. Its like trying to drink through a straw with a hole in it, doesn't work very well. Hope this helps good luck !