4.3L cutting out while cruising.

[Maxum305]

I have a 1999 18 foot Crownline. with a merc 4.3l with 2bbl carb. My problem is sometime when I am cruising 3000-3500rmp it will cut right out like you would turn the key off. But if you a quick and throttle back as soon as it happens it may still keep running. If it stalls completely it will start back up again. I have changed the fuel filter, also checked the inline filter, cap and rotor. What should I do or check next? Any help would be greatly appreciated.

 

[swtch7]

Re: 4.3L cutting out while cruising.

I had the same problem with my maxum sr2. The oil sending unit went bad, it would cut the voltage going to my inline fuel pump. I have heard this is a common problem with these motors.

oil sending unit is pretty cheap, and is located on right side towards the back of the motor (facing front of the motor). Has 2 wires going to it.

hope that helps.

 

[Maxum305]

Re: 4.3L cutting out while cruising.

swtch7 thanks for you reply. I will take a look at is when I get some time to see if I can find it.

Is the oil sending unit for the oil pressure? Is there a way to bypass it so I can try it out before buying a new one?

 

[6meter]

Re: 4.3L cutting out while cruising.

Be careful here. The fuel pump power goes through the oil pressure switch. If the oil pressure drops to low, it will and should cut the fuel pump off. A safety feature to save your motor. Make sure you do have oil pressure.

 

[Maxum305]

Re: 4.3L cutting out while cruising.

Is there a way to test the oil switch?

 

[Maxum305]

Re: 4.3L cutting out while cruising.

I had some time so I went out an took a look to see if I could locate the switch. Is it above the oil filter with two purple wires attached to it?

 

[swtch7]

Re: 4.3L cutting out while cruising.

correct, it is the two purple wires. You can jump those two wires for testing purposes. Like 6meter said, this is a safety feature so make sure your oil levels are good before unhooking it.

Once you jump those 2 purple wires that will send the 12v to your fuel pump (when the key is turned)

good luck and keep us posted!

 

[oldrick]

Re: 4.3L cutting out while cruising.

be sure your one way fuel valve, at gas tank, is not clogging shut. if the little ball in the the valve sticks shut engine will run but then shut off.

 

[Maxum305]

Re: 4.3L cutting out while cruising.

Ordered the oil switch today. Should be in monday afternoon, 40 bucks. Hopefully that takes care of the problem.

 

[Maxum305]

Re: 4.3L cutting out while cruising.

I need some more help. I changed the oil sending unite and thought I had the problem fixed. It worked good the first time out. Then the next time it was acting up again. So I started looking for other possible problems and I found a loose wire on the alternator so I thought that might be the problem, but that did nothing.

When the boat starts cutting out while cursing the gauges go crazy up and down.

Just wondering could a bad alternator cause this to happen. The volt meter is reading around 13-13.5 when idling. and around 12 when cursing.

What do you guys think?

 

[Maxum305]

Re: 4.3L cutting out while cruising.

Any ideas anyone?

 

[sebas54]

Re: 4.3L cutting out while cruising.

To me it sounds like a loose connection. I would check all battery terminals, selector switch, and junctions where the battery cables meet. Also check the fuel pump it self. just connect positive to negative for a couple of seconds to determine if it is running properly.

 

[Todd157k]

Re: 4.3L cutting out while cruising.

When the boat starts cutting out while cursing the gauges go crazy up and down.

That narrows it down to an electrical problem. Do they bounce "full swing" or just pulse?

Full swing:
Look for loose connection at the ignition or bad ignition switch. Disconnect the battery and put an ohm meter on the ignition switch. Turn it on and wiggle the key, see if the reading jumps around. Then check the grounds. Look for loose connections and/or corrosion. If it looks bad on the outside, it's worse on the inside.

Pulsing gauges: (the needle only moving a little)
This is a current problem. Something is shorting or turning on/off by a bad connection. Check for loose wires/connections at the coil and fuel pump (if electric pump) and throttle lock out switch.

 

[Maxum305]

Re: 4.3L cutting out while cruising.

The gauges bounce full swing. I will test the ignition switch. I also forgot that sometimes when you go to start the boat and turn the key nothing happens. Then I just turn the key on and off a couple of times then it starts.

Thanks for the help I will test the switch and let you know how that goes.

If you have any other ideas keep them coming

Thanks again!

 

[6meter]

Re: 4.3L cutting out while cruising.

Make sure your wires are tight on your ignition switch. BTDT. Get a seperate volt meter and read your voltage. 12v at cruise is no good! You shoud have 14.2 volts ALL the time. A loose belt can cause lower readings at idle. Fluctuation gauges indicate loose feed or grounded wires. It all may be one problem. Also look at the big bullet connector, The major boat to motor wire harness.