no fuel to carb

[esg]

Tried starting my boat today it would not start. did some troubleshooting and there's no fuel going to the carb, has external fuel pump, checked for leaks everything is within specs. Wondering how the external pump works in this setup. Its a dual engine setup so I switched the fuel pump to the other engine and fuel is going to the carb and fires right up. any help with this would be appreciated.

 

[Dr Honda]

Is it just one of the engines that won't start?

****EDIT*****


You have external pulse pumps. Basically, there is a diaphragm and 2 check valves. There is a hose that is connected to the engine, that drives the diaphragm, and as it pumps in and out... the fuel flows via the check valves. If the valves aren't sealing... the diaphragm has a hole in it... or there is a leak in the pulse hose... then you won't build enough pressure to run the engine.

 

[esg]

just one engine, when I switched the pump from the non-firing engine to the second engine it fired right up. there's no leaks.

 

[Dr Honda]

OK... you just need to rebuild the pump. And... to be honest... you can probably just take it apart, and clean it. There may be some junk stuck in the check valves.


****EDIT****


Before you try to rebuild the pump... try to draw fuel up the hose on the pump that won't start. The fuel select valve may be plugged up.

 

[esg]

I switched the fuel pump from the non-starting engine to the second engine and it fired right up.

 

[Dr Honda]

So.......... both are running now? If they are... you may have just had a leak in the pulse hose, or intake hose.

 

[esg]

There's no fuel going to the carb on the first engine, but when I switch the fuel pump from the non-starting engine to the second engine it fires right up. I checked for leaks everything is within specs.

checked for leaks on the first engine the non-firing.

 

[Dr Honda]

I thought you put the good pump on the bad engine, and it ran.

I guess I need to go back and re-read everything... Will do that, and gt back.

 

[Dr Honda]

OK... I just misread it before. So... it sounds like you verified that both pumps are working, but you can't get fuel into the one engine. Right?

1) Make sure you can draw fuel up the hose on the side that won't run. The fuel valve may be plugged.

2) Make sure you can blow thought the carbs in the bad engine. Since you have a returning fuel system... you should have a small amount of flow that bypasses the carbs.

3) First... I hope it's not this... but check the compression on the engine that's not running. If you melted the piston on the side that has the pulse hose hooked to it... you won't make a pulse to drive the pump.

 

[esg]

Ok, so thats what the line is for, I was wondering what it was. when I switched fuel pumps to verify there was fuel being drawn up on the non-firing engine I connected all the fuel lines that go to the carb not getting fuel minus the line coming from the nipple in the engine, I used the line from the nipple coming from the second engine there was fuel coming out of the line. I noticed there was oil coming from the line connected to the nipple on the non-firing engine. everything is within specs did not melt piston they ran fine before being stored for the winter.

When I cranked the engine there was oil coming out of the line connected to the nipple on the engine. it was disconnected because i was using the line from the other engine. I taught it was a vent or return line for the oil. But as you stated it runs the fuel pump. how does it work?