One way valve on the fuel line

[scooter4n]

I have 1990 mercruiser 3.0 with mechanical fuel pump.
After engine seats around for few hours it takes about 5-10 seconds of cranking to get fuel to the engine for start. If you started and shut it down right away, you can restart in just one click, like a dream.
I took pump a part, and it looks good, I took it to the local shop and they told me that pump looks good and all, no need to rebuild or new one. Boat runs good.
I was thinking, what if I install one way valve on the fuel line between fuel tank and pump right at the pump?!?!?!?!?!

Another question is electric choke. When I start cold engine and chock closed chock fully opens in like 7-10 seconds ,is that normal, or it should be longer?

Thanks alllllot

 

[Bondo]

Re: One way valve on the fuel line

I was thinking, what if I install one way valve on the fuel line between fuel tank and pump right at the pump?!?!?!?!?!

There already Is 1 at the top of the fuel tank,...
It's called the Anti-Siphon Valve......

Almost sounds more like a Carb Problem to Me....

 

[scooter4n]

Re: One way valve on the fuel line

Carb was rebuild at the shop last year.
What is that valve at the tank went bad?

 

[chiefalen]

Re: One way valve on the fuel line

It's easy to check. Take it off and blow thru it. Check the fuel pickup tube also there is a screen there.Could be bad gas, screen clogged.

After you run it hard do you let it idle for a minute or 2? And when you start up warm do you let it idle for a few minutes?

You should.

What psi is that fuel pump giving you anyway? Easy to check you need 4-6 psi.

When was the last tune up done? Full tune up? The guy who rebuilt the carb set that choke right? Ask him.

Good luck!

 

[scooter4n]

Re: One way valve on the fuel line

Ill try to blow trough the line tomorrow.
I always warm up for few min at idle, and let it idle right before shut down.
Full tuneup and engine rebuild was done last year around same time carb was rebuild. I had blown head gasket and so I put it in the shop. They took all a part and did good job rebuilding.
If I ask mechanic now about how he set the choke he won't remember he works on boats day and night, and Im sure he won't remember my boat.
is there writeup on how to check or adjust choke?
Ill try to get the pressure meeter and check the fuel pressure.
what I did is I got fuel shut off valve, and ill install it right at the carb, and run a test this weekend, ill shut that valve right after I kill the engine, and see if that helps.
thanks.
Please bring it on if you have more input.

 

[JustJason]

Re: One way valve on the fuel line

How exactly are you trying to start the boat?
Walk us through what you do.
You jump in the boat, you put the key in the ignition...... then what are you doing?

 

[cgrooves]

Re: One way valve on the fuel line

My boat acts similar.

Let's just say for arguments sake that all of the fuel that is in the fuel line is running back into the tank after you shut off the engine. Shouldn't there be enough fuel in the carb bowl to crank the engine and keep it running until the fuel pump gets primed and is pumping fuel to the carb again? I would think so.

 

[scooter4n]

Re: One way valve on the fuel line

hmmm, didn't think about that.
Any one has input on that??
How long can you run on the carb bowl???

So if you have same thing going on, did you try anything to fix it??

 

[Fishermark]

Re: One way valve on the fuel line

As Capt Jason asks - What are you doing to to start it? Many people are used to cars with fuel injection. With a carb you need to put the control in the "throttle only" position and pump the handle a couple of times. Each boat is different and to be honest, some just take a little longer. Back in the day, when cars had carbs, you got to know how each car "wanted" to be started. That's just the nature of the beast.

Now it is possible that fuel is leaking out of your carb bowl down into your manifold or evaporating out. It may require a repair... or maybe just a different technique to start.

 

[scooter4n]

Re: One way valve on the fuel line

no fuel leakage at all. Boat in the garage, and I can open engine cover at anytime, and I get no fuel smell, non...
To start I put handle in about 50% forward and crank for 5-7 seconds then it starts. IF I have handle in nutural, straight up, it takes for ever before it starts.
But after it started, you can kill engine right away, and it restarts just fine, right away, and about up to 30min, then it takes longer and longer to start after that

 

[Fishermark]

Re: One way valve on the fuel line

no fuel leakage at all. Boat in the garage, and I can open engine cover at anytime, and I get no fuel smell, non...

When I mentioned the possibility of fuel leaking - I meant internally - down the intake manifold. That's not something you would see nor smell.

To start I put handle in about 50% forward and crank for 5-7 seconds then it starts. IF I have handle in nutural, straight up, it takes for ever before it starts.

That could very well be your problem. A carb needs a couple of pumps (at least) when cold to get started. This allows the accelerator pump to spray some raw gas down the throat to help it start. As mentioned, carbs are different than fuel injection.

 

[mkast]

Re: One way valve on the fuel line

Next time try pushing the throttle all the way forward twice before you try to start the engine, it's called priming.

 

[JustJason]

Re: One way valve on the fuel line

Tada.... and there's your problem.
Glad I asked

carbed engines do require some input to start.... they are not turnkey like modern automobile engines.

What I do is put the shifter in throttle only mode. Depending on your controll you'll have to either push a button in, or pull the handle out. Do not push it into and out of gear with the engine not running, that can cause damage. Give it 2 pumps (move the shifter all the way foward, then back to almost neutral) then set the handle just foward of neutral. Keep the throttle open say just 10%. Turn the key and it should fire right up. Give it a second then pull your handle back in to neutral and let the engine warm up.

 

[cgrooves]

Re: One way valve on the fuel line

So if you have same thing going on, did you try anything to fix it??

I'm trying to figure it out now, and am looking at the operation / adjustment of the choke. If I align the index mark to the center, I noticed that the choke valve wouldn't open all the way when warmed up. I'm working on getting my choke adjusted properly (setting it more toward the lean marks instead of center index mark). I'm also figuring out what the engine likes (i.e. pump the throttle __ times, etc.)

IF I have handle in nutural, straight up, it takes for ever before it starts.
But after it started, you can kill engine right away, and it restarts just fine, right away, and about up to 30min, then it takes longer and longer to start after that

That is probably becuase your choke valve isn't in the 'choke on' position if you leave the handle in neutral. Take the flame arrestor off of the carb before you attempt to start the boat for the first time and the choke valve is probably vertical. Push the handle forward a little to get the idle screw off of the cam and then go look at the carb. The choke valve should be almost closed.

Like the last several posts say.....
You need to pump some raw gas before you try to start. First, it gets some fuel in the throat and Second, it will allow your choke valve to close and operate as designed.

 

[scooter4n]

Re: One way valve on the fuel line

Good stuff. I'll test it Saturday.
thanks all for your inputs.