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2000 MC 305ci Stalls after 20 to 30 seconds

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bayray

Contributing Member
"I have 2000 21-ft Bayliner Ca

"I have 2000 21-ft Bayliner Capri, with Mercruiser 220-hp/305-ci, 2-barrel. Had dealer serviced in July, for linkage cable problem and all has been well. Boat was last used during the Labor Day week-end with no problem, and then again the following weekend. Today I got prepared to go out (temps in low 80's), and the engine would start fine, idle fine, but after about 20 to 30 seconds just quit. After not being able to get it to stay running at the river, we pulled it home and I started my trouble-shooting. It seemed to me to be either carb or fuel related. I replaced the water/fuel filter, checked/cleaned filter in carb. Disconnect fuel line from onboard tank, and used 1-gal can to 'draw' fresh gas from, but having the same problem. Once it dies, I have to 'pump the handle' 1-time to get it to immediately start back up. I've never had a problem with bad fuel, and have had the boat sit 2 or 3 months in the past with no problem. I live in Central Florida, so we use the boat regularily, and don't do any winterizing. Any suggestions would be greatly appreciated!"
 
Keep pumping the handle to see

Keep pumping the handle to see if it continues to run. What type of Fuel Pump do you have Elec. or Mech.? I'll assume mechanical as you mention a Carb.. I'd be suspicious of the pump. Al W.
 
"Al & Guy, thanks for the

"Al & Guy, thanks for the reply! As for pumping the handle/throttle, this would not help. On the water today, as soon as it started, I would put it in gear/full-throttle, and it would take off and then die. I tried pumping & pumping, it wouldn't continue running. I'm thinking it is a mechanical pump, as I never hear a motor run when the key is turned on, and in putting a clear fuel line into a new gallon of fuel, as soon as the motor started to crank, I would see the gas shoot up the tube to the water/fuel seperator.

Any other suggestions?"
 
"Yeah, a 2000 should have a el

"Yeah, a 2000 should have a electric pump, and as such would be also be equipped with a (no) oil pressure fuel pump shut off switch.

The switch is bypassed during cranking so that is why the engine starts for a few seconds, but then if there is a bad connection at the switch or the switch is bad the fuel pump will not continue to run and the engine will die once the fuel provided during cranking is gone. It's a pretty common problem and an easy fix."
 
"OK! You guy's are GOOD!

"OK! You guy's are GOOD! Looks like I found the electic fuel pump (hidden by the large coolant hose). I'll need to borrow some line wrenches, I don't want to strip the brass nuts in getting to the filter on the fuel pump. Guy, do you know if the filter would be at the top of the pump? It has a double-connection similar to where the stainless line connects to the filter at the carb intake."
 
"Dave, I got the fuel pump out

"Dave, I got the fuel pump out, and found the screen. Although it didn't appear to have any debris in it, I sprayed it out throughly with carb cleaner, and reassembled it...same symptom.

The oil pressure switch, is this the same pressure switch that indicates the pressure on my gauge? It looks like it is in the block, on the starboard side, about 2/3 toward the rear of the engine. I know when the motor does run, my gauge is showing 45 psi.

I can say this, I had this replaced by service facility about 2-years ago due to corrosion, and leaking oil. Although there is no oil leak, you think this may be causing the problem with the motor stopping?"
 
"There are actually two oil pr

"There are actually two oil pressure switchs and one sending unit. The sending unit is connected to the gauge, and does not have anything to do with fuel pump operation.

There are two oil pressure switchs (located just above the oil filter on the engine block), one is a single wire switch that is connected to the low oil pressure alarm, and the other is a two wire switch that provides power to the fuel pump when there is oil pressure, and cuts off the power when there is no oil pressure. To bypass the the two wire switch for testing purposes, just remove the two wires and temporarily connect them together."
 
"Dave, I appreciate all your i

"Dave, I appreciate all your input, as well as everyone else! I will try your suggestion in the upcoming week, as I've just put the engine covers back on, and moved the boat back to its storage. I'll let you know the outcome after temporarily jumping the 2-wires together...(ONLY temporary)!"
 
"Help! I got to the 2-wire O/

"Help! I got to the 2-wire O/P switch (I think), removed the connector and used a paper-clip to 'jumper' the 2 wires (purple & purple/yellow). Had same result. 1 'Pump' of the handle, fired right up, idled perfectly down from 1000-rpm to about 575-rpm, and after running for 45-seconds, it just quits.

It would fire back up, but only after slightly giving it some throttle, and continue running smoothly for about 20 to 30-seconds.

Dave, on your description of the location of the O/P switches, you mentioned 1-sending unit, and 2-O/P switches. I only saw the single-wire pressure switch or sending unit (which when I disconnected this wire, the O/P on dash gauge went to zero). On the other end of the tee, was the 2-wire unit that I jumpered. Am I missing something, possibly another 2-wire oil pressure switch? When I disconnected the single-wire, my alarm didn't sound off, which is why I think I'm missing something. Even when the 2-wire switch was disconnected and NOT jumpered, the alarm would not sound.

Seems hard to believe this would be ignition or spark related, as it will fire up just fine, idle fine, throttle up fine. I don't believe I have an IAC, as this is a 2-bbl carb. Do you think it could be the fuel pump? If so, do you know if this could be tested at a shop? I'd hate to spend $200 on this, and it not be the cause.

Any other suggestions greatly appreciated.

Thanks,
Joe"
 
"Ok, if the engine will not co

"Ok, if the engine will not continue to run with the oil pressure switch bypassed, then reconnect it. Ay this point I don't think it's the fuel pump.

One other common thing that will cause this symptom is a bad ignition sensor. There is a easy Thunderbolt ignition troubleshooting procedure in the Mercruiser service manual."
 
"To All,
I tried the jumper w

"To All,
I tried the jumper wire from B+ to Coil+, with same results. My 'audible alarm' came on immediately, even with the ignition in OFF position, but I would believe this to be normal, as the coil+ now has power and back-feeding to the alarm.

Engine starts, dies within 30-40 seconds, I can immediately crank back up, it will run for 20-30 seconds, and continue dying/recranking, etc.

I also re-tried the O/P bypass again, just to make sure, as it was starting to get dark the other evening, and also had the same results.

Any other suggestions?"
 
"First you need to isolate som

"First you need to isolate some stuff.

First to do is when the engine shuts down, shut key off immediatly and go to the carb and pump the throttle and see if gas sprays down the throat of the carb, If it does then the carb has fuel.

To test the fuel pump and oil pressure switch I would do this.
Disconnect the fuel line at the carb. Attach a long piece of fuel line to it and put the other end into a 5 gallon bucket outside the boat. Jump out the oil pressure switch. Turn key on and the pump should pump fuel nonstop until you shut the key off.

I am attaching a wire diagram to make a remote starter/jumper set up that I have myself. It can be used to isolate the controll side of the wire harness.

Disconnect the large connector that goes from the engine to the dash, the one with all the pins and sockets in it. and hook yp the 2 switch assembly as I have drwn it. You will need to buy 2 switches, one is a 12 volt on/off and the other is a 12 volt momentary switch.
You will need about 6 feet of 14 guage wire.
Use red for the battery wire, use purple for the +12 volts to the coil and yellow for the starter solenoid connection.

Doing this will isolate the wiring harness between the motor and the dash.

When it is hooked up then turn on the on/off switch and this will apply 12vdc to the igniition system. then push the momentary switch and this will cause the engine to crank. ONCE IT STARTS let go of the momentary switch to disengage the starter. *****NOTE!!! TO SHUT THE ENGINE OFF YOU MUST TURN THE ON/OFF SWITCH TO OFF!!!*****

The way the electric fuel pump works is,
When you crank the engine over it will start to produce oil pressure, when it reaches ~15 psi the oil pressure switch closes and the fuel pump is allowe to turn on. There is no relay it is 12 vdc direct after the o/p switch. Thus even if the guage reads oil pressure that does not mean the switch sees that pressure. It may see it momentaraly and then it opens and shuts the pump off. This is of course if it is a fuel issue.

If you remote start the engine with the harness disconnected and it still shuts down and you absolutley confirm the fuel pump is working and the carb is getting fuel and it still shuts down then it has to be an ignition related issue.

221358.jpg
remote starter kit
 
"Thanks alot KGhost. I'll

"Thanks alot KGhost. I'll try to do this tomorrow, although I need to look at 2 auto problems also.

I'll update this post with results once I get this tested."
 
"Kghost, I did the first 2 ste

"Kghost, I did the first 2 steps you recommended.

1. Start engine, as soon as it quits, immediately turn the key off, and had my son pump the throttle, and 'YES' fuel does spray into the throat of the carb.

2. Jumpered the 2-wire connector going to the O/P switch. Disconnect fuel supply line at carb, put a 7/16th I.D. fuel-line with clamp on the factory line, and ran to outside of boat into a 5-gal gas can. Now, with the key in the 'ON' position, NO fuel is pumping. If I attempt to 'crank' the engine, fuel does flow into the can.

I didn't proceed to installing the remote start/jumper setup I made, as I wanted to run the above items thru the you and this forum to see what suggestion I may receive, especially without having fuel being pumped with the ignition switch only in the 'ON' position. Maybe I do need to just continue with the remote start/jumper setup, but I will wait on recommendation.

Thanks again everyone!"
 
"UPDATE...It DOES appear to be

"UPDATE...It DOES appear to be 'power' to fuel pump related! I ran jumper wires from Fuel Pump connector direct to B+ & B- and the pump immediately started to run. I 'fired' up motor, and let it run 5-minutes up to temp of 170, without it dying.

Does anyone know definitely, that with the key in the ON position, the fuel pump should be running? I am most certain that I've not heard the 'humming' from the fuel pump before, even before the engine cranked up.

With fuel pump power coming from the O/P switch (purple/yellow wire), should I have 12-v at the fuel pump connector?

I also put everything back to 'normal' and motor exhibited same symptom as originally posted. I then tried to ONLY jumper O/P-switch connector again, but same issue."
 
"Joe Flanagan
If it works wel

"Joe Flanagan
If it works well with B+ and Ground connected to the fuel pump and not when O/P switch is jumpered, take a close look and the grounding of the fuel pump.
Bert"
 
"Bert, other than the wiring g

"Bert, other than the wiring going to the fuel pump, there is no physical ground, as the fuel pump is mounted on rubber grommets at the top and bottom.

Kghost, I went ahead and tried your wiring suggestion. Motor started fine, but ran into the exact same symptom.

I ohm'd the black wire from the fuel pump connector to ground and it was definitely grounded correctly. I ohm'd the purple/yellow wire from the fuel pump connector to ground, and it was open (as expected). I ohm'd from the same point (purple/yellow wire at the fuel pump connector) to the the purple/yellow wire at the connector for the O/P switch and had a solid connection.

With everything connected normally again, I started the motor, and checked voltage at the fuel pump connector, and I don't have ANY voltage. At this point, I have to believe it is the O/P switch, although not sure why when I jumper the connector going to it, it still fails.

Any other thoughts on this, before I purchase the O/P switch?"
 
Joe Flanagan
It appears all i

Joe Flanagan
It appears all is well around the fuel pump connections. Check the voltage source and input to the O/P switch. Maybe there is no voltage getting to the O/P switch.
Bert
 
"Joe

Do you have a test lig

"Joe

Do you have a test light? Using a volt meter is ok but may not tell the whole story.

Get a test light and test it across the battery and take note on the brightness of the light!!!

Now with the KEY on, probe the test light at the fuel pump + 12, the oil pressure switch + 12 that goes to the pump, and the +12 that goes to the oil pressure switch.

The light should be very close to intenseness as the battery test done earlier.

It would appear as said before by Bert you need to trace the 12 volts there may be a bad/loose connection that drops out after the engine starts.

Also when you jumped 12 volts direct to the pump where was the pump connector when you did this. The connector could also be the source of your problem. They ( mercruiser ) have had issues with the connector in the past. Make sure you have 12 volts to the connector and also whe pluged into the pump.

Also to absolutley be sure you have a good ground reverse the test light leads, connect the negative side of the test light to +12 volts and the other end of the light to the negative going to the pump. The light should be nice and bright. Also wiggle wires as you do all of these tests.

Let us know.........."
 
"Joe one more thing,

The po

"Joe one more thing,

The power to the fuel pump does not come from the o/p switch it goes thru it. The sitch is a normally open switch.

It troubles me that when you hook up my switch and jumpered the o/p switch you should have had 12 volts directly to the pump.

ARE YOU SURE THE CORRECT WIRES ARE GOING TO THE CORERECT TERMINALS AT THE OIL PRESSURE SWITCH????????????

It almost sounds as if someone put the wires on the wrong terminals and that cause it to be closed when started and then opens soon after.

Just a thought."
 
"Thanks Guy, Bert & Kghost

"Thanks Guy, Bert & Kghost. I will try each of these suggestions. I don't have, but will get a test light and try your instructions.

The connector for the fuel pump is located at the top of the intake manifold, in front of and to the left of the carb.

The wires for the O/P switch are in a molded 2-wire keyed connector that attaches to the physical O/P switch. I haven't been able to find this particular switch online, but in doing further testing, I'll take a pic of this area (with the tee & sending unit) and post it.

I'll never complain again about the amount the professionals charge, although you guys make this troubleshooting a little bit of fun, and give me a good understanding of how all this stuff comes together. I'll keep you updated, and thanks again to everyone!"
 
"[b]<font size=""+1"">You guys

"<font size=""+1"">You guys </font><font size=""+2"">ROCK! </font>Picked up a 12-v probe light ($2.99 at AutoZone), and started at the O/P switch, no voltage into it. Started to follow supply lead, and it went about 6" to a spade connector. I pulled this apart, and had intermittant light from the wiring harness. Turned out to be full of gunk, oil, dust, dirt! Used a little 'degreaser', sprayed clean, reconnect and the fuel pump made a BEAUTIFUL sound. Boat now cranks, and STAYS running.

I wanted to thank EVERYONE for their input. For what seems like such a simple problem, my hats off to you, for you persistance on making suggestions for me. I have this web-site as a Favorite, and at the TOP of the list!

I will throw a party for everyone that helped me out! Dec. 31, 2008. If you get to East/Central Florida, hit me up!"
 
"Joe,

Great job!!! All you

"Joe,

Great job!!! All you need sometimes is the simplest tools to troubleshoot a problem effectivly.

On a 12VDC system a test light is one of the best troubleshooting tools there is. Of course when you get into efi that is different but for standard 12 vdc its the best!!

If possible I would eliminate that spade connector if you can. Cut and SOLDER, shrinkwrap the wires to eliminate the potential.





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