Engine won't start - fuel delivery problem

[gary gerber]

HELP!

I have spark, compression check of 95 lb. each cylinder, plugs are dry.

Cranking the engine ( water inlet closed ) does not fill the fuel filter, does not fill the fuel pump sediment bowl or pass through the "U" tube feed to the carb.

So far I have: rebuilt the mechanical fuel pump, disassembled my 3 year old MM carb (bowl was empty), installed a new fuel filter, removed all fuel line connections and blown air through them ( With a hand pump I pumped air into the fuel tank line to check for blockage of the pick up tube then set the pump in suction mode and attempted to draw fuel from the tank... I did get fuel but it didn't run out of the disconnected line. ) With a gravity feed mounting should fuel simply run out of the disconnected fuel line (to the lower mounted filter)? Cranking the engine did not fill the SIERRA water separator filter with fuel ( This is a filter model I have been using for years ).

Any fuel collected so far ( I even drew a sample from the bottom of the fuel tank ) has been clear of any sediment or clouding.

I have a metal fuel tank, I was wondering if there is a mesh screen on the pick up tube that is obstructed with build up as a result of the ethanol factor. This 39 year old boat is stored with a full tank plus Sta-Bil for Winter layup, this is the first time in all these years I have encountered this problem.

I welcome any input, I have exhausted my limited knowledge.

[smosher]

Hi, I'm not sure what you have tested. In any case the gravity system will only work if the fuel pickup tube is filled and the output from the tank is filled, sort of like syphoning. This assumes your run is somewhat downhill
in order for the fuel to gravity feed. What do you mean you got fuel but not from the dissconnected hose, where did you get fuel from ?

I would suction the fuel until it came out of the filter, then reconnect all of your fuel lines and use the priming lever on the pump to fill the carb. If the fuel doesn't come out
of the filter then I would try the same thing making sure fuel got to the filter.

Did you try it with the fill cap loose to see if maybe you have a vent problem ?

Steve

[MikeB.330]

The only thing I can think of to add to Smoshers post is that I would hook up the suction pump to the fuel line just before the engines fuel pump. It sounds like you just have a completely dry fuel line and the pump needs a little help priming.

[gary gerber]

Thanks for the responses. When I made reference to getting some fuel from the disconnected line from the fuel tank I used a hand pump to suck from the tank line into a small container. I did get fuel but as I stated There was no fuel simply running out of the downhill line.

I disconnected the fuel delivery line from the pump to the carb and then pumped the primer arm, but no fuel was expeled from the carb end of the "U".
Also, after a number of strokes of the pump primer the pump sediment bowl did not fill. this is why I began looking at connections before the fuel pump, the feeder line, filter and the fuel line from the tank.

Reading about tanks having to be removed and flushed is like a nightmare.

In forty years of sailing I never encountered this type of problem before.

[gary gerber]

I forgot to mention that I did suspect the fuel tank vent. I removed the fuel tank filler cap before all of the pump tests. I had someone at the tank filler to listen for air bubbles when I pumped air back through the fuel line. I did this to hopefully dislodge any sediment that may have accumulated at the pick up tube. My helper said they did hear a few "burbles" when I used the single stroke hand pump, but honestly they may have been mistaken.

[Marian Claire]

I had to clear my pick up tube once. We used a small compressor. I think it hit 50-60 PSI before it cleared. After clearing you could hear bubbles just using lung power to blow thru the line. Still had problems with gas flow in rough seas after that. So pulled my 40 year old stainless steel tank and found lots of crud. Dan S/V Marian Claire

[gary gerber]

I have a small compressor, I plan on trying your suggestion this weekend.

[gary gerber]

Using the portable compressor worked perfectly, I then used a siphon blub to draw fuel into the filter and fuel pump.

The blockage was cleared and the engine runs smooth as normal. Thanks