Not getting fuel. Need help

[larrytbull]

My 7.4 l inboard stopped while at dock.
I figured it was fuel filter as it was not getting gas to carb. I just replaced fuel pump a month ago, so figuring no pump.
I cranked engine but no fuel going through to carb. Pulled fuel line from fuel pump to engine. Ran carb cleaner to it. It was clear. Tried again. No fuel still.

Pulled both filters. And both were dry. Filled both with fuel hoping it was not primed. Cranked again no fuel. Went to fuel line near flow sesnsors. And looked for clogs. Nothing there. One thing to note. There was no fuel dropping out as I pulled the flow sensors. I am out of ideas. Any help appreciated thanks

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[GrandMaster]

Mechanical fuel pump or electric?

And it need to be asked...fuel in the tank?

 

[larrytbull]

Mechanical fuel pump. And I know I left myself open to the second question. Full tank of gas

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[tdschafer]

Larry,

I just had a problem where my boat ran only up to about 2000 rpms then would decrease to less than 1000 rpms until I pulled the throttles back. The fuel pump was replaced & the carb rebuilt but still was not working. It turns out my fuel line was bad. They ended up replacing it from the fuel selector switch all the way to the carb I believe. I know it's different from your problem but I wonder if you have a bad fuel line too that is blocked?

 

[ardeprint]

I don't know if this applies to your year, or your mechanical pump, but when you are low in oil or oil pressure this will shut the fuel pump. You may have disconnected the cable from the sensor to the pump or you are low on oil.

Its a stretch, but in a bout everything is worth mentioning.

 

[Bt Doctur]

mechanical pump works off the cam,cam lobe worn away, bad fuel pump, anti-syphon clogged shut

 

[GrandMaster]

If you are 100% sure your fuel pump is working than stuck anti-syphon valve on top of the fuel tank would also be my next guess.

 

[PlayDate]

Larry,

What troubles me is that the filters were dry before and after you changed the fuel pump. That leads me to think you have air getting in the system. What I would do to trace it is buy a 3/8" fuel bulb ($8 for an outboard fuel bulb) and start testing from the first tank hose and move towards the carb. You might have to buy a fitting to make it compatible with the hose ends you have. Place you finger over the output end after you squeeze it, then release the bulb. This creates a quicker suction siphon than the check valve in the bulb.

This will tell you where in the fuel line the problem is. It is possible that the pickup in the tank has a problem.

-John

 

[larrytbull]

thanks for all the responses. I traced it down to a few things. 1. I was replacing wrong fuel filter, I was replacing generator fuel filter (rookie mistake) 2. there seemed to no fuel dripping down from tank selector. I finally solved it by blowing air up the fuel line then using a bulb to prime it back.I also ran compressed air through my fuel flow sensor to ensure it was not clogged, All seems to be working now

 

[tdschafer]

Larry,

A quick way to diagnose the anti siphon valve is to switch that motor fuel supply to the opposite tank. If its a vacuum created by the valve the motor should run on the other tank.

Edit: I guess this info was too late! Glad that you figured it out.


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Todd