2001 4.3 L Merc Water in fuel or Fuel pump problem?

Hey I'm new to the boating.

2001 Regal with a 4.3 merc only 75 hrs.
1St time drained tank had carb rebuilt worked for the season (last year) $700.00

This year -

Starts and stalls put fuel additive top it up with gas in and replace separation filter starts up and runs for the day. ( boat was winterized with stabilizer )

Only the second time out this year

Today - starts, in the first 5 min under load dies put another separation filter on nothing. Check fuel filter no fuel. Took it home disconnect the fuel line at the carb and no fuel. Wired pump to constant 12V and had fuel put everything back together and started and run no problem (on land). The one thing I noticed is the pump wasn't coming on when the key was in the run position. Not sure if the carb can pull enough when running under no load? Metered switch seems okay. I could only see 2 little drops of water in the old water separation filter. Is the fuel pump suppose to run all the time or only when the pressure drops?

Can't see that much water getting into the tank or condensation.

Any idea? still water in fuel or fuel problem?

Thanks

I try and tell people to get an external fuel tank with fresh fuel and run it and see what happens, you will know, also get a manual and check fuel pressure or sombody will tell you what it should be, ( don't know off hand ).

Look at the tank see where the fuel gets pulled to the fuel pump ? Remove hose off fitting and screw out the fitting the fuel pickup tube will come up with the fitting.

That fitting is a one way valve blow thru it and make sure it is working good and that the fuel pickup tube is clear.

The carb has a filter in the fitting where the fuel enters clean it.

You could fill the water sep filter with fuel before you install it.

Thanks for all the input.

From what I found the fuel pump should come on when the key is turned forward to the start and run position until the oil pressure builds up. It does not. I jump the oil safety switch and the fuel pump came on right away when the key was turned.

Does it make sense that it could be a failing oil switch? Just not 100 percent of the time?
Is this common?

Thanks again

Mike

maybe failing relay.

See you crank the juice to the pump goes off the starter then the oil gets pumped up enough to open the relay from the oil sender.

chiefalen said:

See you crank the juice to the pump goes off the starter then the oil gets pumped up enough to open the relay from the oil sender.

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Am I the only one who can not understand what the F*ck that sentence says.....................WTF!!!




On a V6 or any typical carbed marine engine with a electric fuel pump, at the location where the oil pressure sending unit is, there is also a pressure switch also.
The fuel pump will not turn on ontil the pressure switch sees ~ 10-15 psi. This is incase you loose oil pressure the motor will shut down/run out of fuel.

So when you turn the key to the on position nothing will happen unless the oil pressure switch is closed (from oil pressure or jumped with a jumper wire)

It sounds like your pressure switch is bad. based on your last post so that would be the first place to start. replace the switch.

Also when you replace a water seperating filter it is best practice to pre fill (at least most of the way) with fuel. any fuel pump has a hard time pulling all that air out of the filter.............

Also make sure the fuel pump connector is on propperly, back in the early 2000's there was a updated fuel pump connector issued. You may want to check with a dealer or maybe someone here has that info. Due to the fact that your boat has such low hours this connector (fuel pump connector) may be suspect also.

Thanks for your input. Just replaced the oil pressure switch seems better however there is still a bit of a sputter when you hit the throttle hard I still think I have a water issue. I was told the carb bowl may have water in it so I will clear that. Also my fuel cap is a perko combo with the vent built in. Anyone here issues with these? The other thing I was going to do is add a second fuel/water filter (racor) however I found one that will match right up with the housing already there it is a racor B32020MAM. Anyone use these? Just don't understand how I can get that much water in the fuel. I guess it is the most common problem with a boat

Thanks

Mike

...there is still a bit of a sputter when you hit the throttle hard...

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By sputter do you mean misfiring or a delay in throttle response? A delay or hesitation could mean the accellerator pump is worn and not providing the burst of fuel needed.

No it's a delay in throttle response. The carb was just rebuilt last season. only seen 10 hours on the rebuild. I think its water. Whats the odds that there is water in the carb bowl? they (the shop) tells me you will have a hard time burning it through and you have to clean it out. Tomorrow remove filter and see if there is water in it.

The carb was just rebuilt last season.

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Doesn't mean it is working today. With a cold engine look into the carb w/the choke plate wide open and push the throttle. You should see two strong streams of gas. If you don't the accellerator pump is not pumping. You need to replace it.

Update.....

So the accellerator pump is working fine. Removed the new water / fuel filter empty in a jar. 50/50 water and fuel. Removed top part of carb bowl has a bit of water in it. After ruling out the tank and all hose clamps are good I went to the cap. Which is a combo fill and vent in one (Perko). Googled the part and found it is suppose to have an O ring which has never been on it. Spoke to perko they are sending it free in the mail. I think this should fix the problem. The next one will be draining the tank. Any ides that are safe?

Hard to believe the 2 years of hell with this boat and no time on the water could be caused by a free O ring. I guess the service guys don't look for this type of things not enough money in it for them.

Thanks

Will keep posted once I get the ring installed providing it does snow before then.

check with a dealer or somebody who knows, there is a small vent hole in the fuel fill cap ( perko ) if it is mounted a certain way ( facing up ) all the rain water etc. runs down into the tank and you still wind up getting water in the fuel anyway. if mounted on the bottom there are not any problems.