Motor won't start?

[[email protected]]

I have a 5.0GL Volvo motor that won't start. When I apply carburator spray in the intake of the carburator, it would fire right up. Once I turn it off, it will not start. I replaced the batteries. The boat has not been fired up since a couple of years after winterization. Any recommendation in what I should look at or replace? Fuel pump, fuel filter, spark plugs...etc.

 

[o2batsea]

If it fires on starting fluid, then you have a fuel delivery problem. But from here on out, don't use starting fluid on any engine that you value. Dribble a small amount of gasoline down the carb instead.
You are sure that you have the fuel tap open on the top of the tank? You are sure that you have gas in the tank? Stupid questions, but gotta ask.
Take the supply hose off the carburetor. Stuff some paper towels around to soak up gas in case. Have someone crank the engine and see if any gas comes out of the supply line.
If so then you probably have a stuck needle valve inside the carb. That's a zero dollar fix, but you have to take the top off the carb to loosen the needle valve, and then put it back together.
If no then you probably have a bad fuel pump which means a new one.
If neither of these fix the trouble, then you have a clog somewhere. Easiest way to clear a clog in the tank is to blow air back thru the supply hose until you hear bubbles inside the tank.

 

[[email protected]]

So, I removed the gas cap and disconnected the fuel line from the carburetor and started the engine and gas was flowing. Put everything back and engine still would not turn over. Applied small amount of gas in the carburetor and it fired up fine. I shutoff the engine and tapped the side of the carburetor with a wrench thinking it might loosen the needle valve. Fired up the engine and it fires right up again, again, and again... I'm not convinced the problem is fixed by tapping the side. I did noticed that the butterfly/throttle valve is wide open at all times even when the motor is not running. There is a loose/free nut hook under the cable that controls the throttle. Is this suppose to be loose and is it normal for the valve to remain open? Where is the needle valve located? Do I need to take the carburetor apart to get to it?

Greatly appreciate your help o2batsea. You saved me $$$ and taught me a lot about my boat...

Ralph

 

[1stboat]

If your butterfly is wide open then you might have a throttle cable issue. When the engine did start, did it surge or was it a smooth idle?

 

[[email protected]]

When I started the engine, it started right up and idle was smooth. I was informed that the butterfly valve is controlled electronically by heat sensitively read back. Am I on the right path?