Gas not getting to engine

[L. Reed]

Hey guys, I have twin Yamaha 200 HPDIs that have always run great. Today, after winter lay-up, I fired her up for a shakedown cruise, only to have the port engine cut off once the fuel in the line was burned. Stbd. engine runs fine, & they share the same tank. Primer bulb on stbd. engine pumps tight, & I can feel the fuel in the bulb. Port primer bulb does not get tight. Pulled fuel line from bulb, & spin-on filter, no gas all the way back to the fuel management flow sensor. I have not gone in front of the flow sensor yet, but there is nothing else between the tank & the sensor, so...................

I just had the sensors replaced 2 years ago, is the impeller frozen, can they be cleaned / serviced, or do I have to replace it again. Can I bypass it / take it our for now and run the boat rather than spend $200.00 on a new sensor right now?

Thanks

[rodbolt17]

I would more suspect a collapsed fuel line or a bad anti-siphon valve.
even with a stuck paddle fuel will flow through the flow sensor.

[L. Reed]

I checked the fuel line as far back / forward as I could. Is the anti-siphon valve inside the tank?

[muskrat1]

Have you tried swapping the hoses going to your engines?

See if the problem follows the hose. (Engine that was NOT running should run, engine that WAS running should NOT run now)

If it does follow - problem is in that hose some where.
If it doesn't follow - problem is on the engine side.

Anti-siphon valve, is in the primer bulb.

[L. Reed]

Thanks Muskrat, I was planning on trying the swap when I get off work today, just to make sure. So far, everything on the fuel flow sensor outlet side is bone dry. Going on the inlet side this afternoon, to see if fuel is making to the sensor.

[FabricGATOR]

Hey guys, I have twin Yamaha 200 HPDIs that have always run great. Today, after winter lay-up, I fired her up for a shakedown cruise, only to have the port engine cut off once the fuel in the line was burned. Stbd. engine runs fine, & they share the same tank. Primer bulb on stbd. engine pumps tight, & I can feel the fuel in the bulb. Port primer bulb does not get tight. Pulled fuel line from bulb, & spin-on filter, no gas all the way back to the fuel management flow sensor. I have not gone in front of the flow sensor yet, but there is nothing else between the tank & the sensor, so...................

I believe that you may not be rigged correctly from this description. Its probably not the cause of you discrepancy but what you describe seems backwards.

It is my understanding that from your tank your fuel should go to the filter/water separator, then to the flow transducer, and then the primer bulb to the engine.

Is this how you are setup and I just didn't read it correctly?

I think I would try to blow back into the hose an see if its blocked. Depending on the depth of your tank and the amount of fuel in it you may be able to do it manually. The primer bulb works by two check valves both allowing fuel to travel only towards the engine, so don't try to blow back to the tank through it. If I were going to use compressed air, Open the fuel fill to allow the air to escape. Sometimes the tank vent can be restricted or not allow enough air to escape quickly enough. The last thing anyone needs is to rupture the tank, that would be a mess to clean up and the bilge pump would not be the solution for a number of reasons.

Do you trailer and fill up at the pumps? Do you burn the E-10 gas with ethanol?

[L. Reed]

OK, How's this sound. I swapped the fuel lines and the "good" engine ran out of fuel, & the "bad" engine cranked & ran fine. After hanging upside down in the bilge for a while, I descovered a small hole in the bottom of the port fuel / water separator, so everytime I sqeeze the primer bulb it catches air, can't form a vacuum to pull the fuel. So, once I change the filters, I should be fine. We'll see.

[L. Reed]

Fabrigator, I may not have been clear, It goes, fuel tank, fuel management sensor, fuel / water filter, primer bulb, engine. She has run perfect for 12 years like that. Thanks though.

[muskrat1]

OK, How's this sound. I swapped the fuel lines and the "good" engine ran out of fuel, & the "bad" engine cranked & ran fine. After hanging upside down in the bilge for a while, I descovered a small hole in the bottom of the port fuel / water separator, so everytime I sqeeze the primer bulb it catches air, can't form a vacuum to pull the fuel. So, once I change the filters, I should be fine. We'll see.

Perfect. That takes your engines out of the equation. Sounds like you are close to fixed.

Make sure your water/fuel separator housing is still good.

If your filters have been on there long enough, where they started to break down I assume due to corrosion? You want to make sure the housing is still good. Also, you might want to change filters more often.

Last = change the other filter at the same time.

[L. Reed]

Yea, that's on me. I never got around to changing them last year, & now it's rusted out.

[99yam40]

You are lucky you did not dump a load of fuel into the boat and go boom.
That rusted through in 1 year?

[L. Reed]

No, 2 years, I never got around to changing them last year.

The air / fuel leak was the problem, it can't pull a vacuum to feed the HPDIs when it's sucking air. New filters installed & primed, running fine again. Thanks for the suggestions. Safe boating to all.