2003 21i died on the water today

[chuckhoenig]

Hey, I was out on the water this morning towing my wife and son in a tube at about 15mph. My engine bogged down, then died. Was able to turn it over, and start it, then it died immediately. Wouldn't start at all, and had to get towed in.

Started troubleshooting as usual. Gauges all looked fine, and I put a brand new battery in June. Popped engine cover, and did notice a water line on my starter from some heavy rains we got about a month ago, but I've run it with no issues since then for about 8 hours.

I did see some trans oil in the bilge water, so I popped the floor board, and noticed my trans oil dipstick was sitting loosely in its housing. and my trans oil looked like pepto-bismol.

Engine oil looked fine on the dipstick, so I can't understand why I lost power.


I'm thinking the rainwater penetrated the transmission oil, and maybe the starter/solenoid and caused as short as well as the trans oil to become compromised. Doesn't really explain why it has ran with no issues for so long since the rainwater penetrated.

I have a 350Mag MPI. Not sure of transmission model, but will check tonight.

Thanks!

[chpthril]

Rain water on the solenoid and starter motor can create to issues, but these would be seen during cranking and not be a cause for the engine to die once running. Milky transmission fluid is an indication of water in the fluid, but again, would not cause the engine to die.

In order to run, an engine needs air, fuel and spark, one is no longer present.

[boatwakes]

Chuck, your transmission oil cooler is most likely the cause of the pepto and should be replaced. If you have the mercruiser engine, it's located right next to the starter just behind the raw water pump. Flush and flush and flush and flush with new fluid and then flush again. Once the clutch pack sees water it starts to disintegrate and when it starts to slip, itll be time for a new gear.
Now for the engine I have a couple questions:
1) Does the motor turn over and just not start?
2) Now that the boat is out of the water, have someone watch the propeller while you crank the engine. Does the propeller spin? If so stop immediately, your transmission has locked up and will need to be replaced.
3) If everything with the prop and transmission is normal, do you hear the fuel pump cycle when the key is turned to the "on" position?
4) If so, test fuel pressure at the rail on top of the engine. You may have to purchase an EFI pressure gauge but your fuel pressure should come up to about 30psi and not fall off immediately but hold relatively close to that pressure once the pump cycle stops. If you have no fuel pressure, you may be out of fuel.
5) If fuel pressure is okay, do you have a spark checker? If not, $4 at the auto parts store. Hook it inline between the ignition coil and the distributor cap and crank the motor. Do you see spark? If not, replace the ignition coil AND the ignition sensor located inside the distributor. SENSOR ASSEMBLY (#87-892150Q02) $65, COIL KIT (#300-8M0079202) $66 both can be found at perfprotech.com. Any other symptoms or problems?

[chuckhoenig]

Thanks for the responses

Boatwakes:

1. Boat won't turn over, starter won't engage.
2. Boat is in a lift, with prop in water, but I can see the drive shaft and it's not turning. Floor board pulled out.
3. Fuel pump cycles.
4. Don't have those testers, I will buy if the starter is functioning properly. I should have plenty of fuel, just filled it up last week. Only ran for two hours.

Here's what I've done so far.

1. I changed the trans oil, after pumping out all the bad fluid.
2. I changed the engine oil. It looked fine.
3. pulled the starter after testing it on the motor. It was getting power but not spinning. I'm going to bench test it here in in few moments. Will let you know what happens.
4. Tested battery, good charge on that as well. Over 12volts loaded

Thanks for all of the help!!

[chuckhoenig]

I bench tested the starter, and it's fried. I'll get a new one tomorrow and replace.

Would a bad starter/solenoid effect the the electrical system enough to cause the boat to stop running?

If the boat starts, is there a way to cycle the trans oil without running the boat? I know it will need to be changed again, I just want to try and cycle it without having to really run the boat.

Thanks for all the help!

[boatwakes]

There's a 90amp fuse thats connected to the battery post on the starter it looks like a little white square, check that too because that could cause the electrical issue.

[boatwakes]

When the engine is running, the pump in the transmission is running too so you don't have to take the boat out and drive it but you do have to start and run the engine to cycle it. I would still recommend replace the transmission fluid cooler.

[chuckhoenig]

Thank you!! I will check that as well.

[chuckhoenig]

OK, I replaced the starter tonight, and it fired right up. Then died after I tried to rev the engine in neutral. Bogged down then died. Now it turns over, but won't fire. When it was running it sounded normal. Not missing or anything that I could tell.

I'm thinking fuel, but not sure. Anybody know how to troubleshoot the fuel system?

Mercruiser 350Mag MPI

I was planning on changing the tranny oil again tonight, but didn't have the motor going long enough.

Thanks for all the help!!

[TeamAllen]

Locate a feul pressure gauge.

[boatwakes]

As Mr. Allen said, get an efi fuel pressure tester from the auto parts store as well as a spark checker. Fuel pressure should be 30psi+-2psi when the engine is cranking and or running. Be sure there is fuel in the tank or hook up an external tank with known good fuel. There are several possibilities when diagnosing fuel so first check pressure with the key turned to the on position only, record the reading and then record the reading when cranking the motor. There should also be liquid fuel at the schrader valve where the tester connects and if there's air, the rails are not getting fuel. Keep us posted.

[chuckhoenig]

OK, here is an update.

When I turn the key, I can hear the fuel pump kicking in.

Here is what I did today.
1. Drove to three different auto part stores including sears to buy and or rent a fuel pressure tester.
2. Bought parts and made my own.
3. Located Schrader valve, and my homemade rig wouldn't fit.
4. Depressed release on valve, and very little gas came out.
5. Turned Key several times to fire fuel pump with valve depressed to expel air.
6. After air was expelled, very little fuel came out.
7. Didn't take a genius to figure out that there isn't 30psi in the fuel system.
8. Engine turned over and would start
9. Check for spark with spark tester and had spark.
10. Made the command decision that the fuel pump although sounding like it works, is not getting enough fuel to the fuel rails.
11. bench tested the fuel pump, without a guage, with water instead of gas and it did pump.
12. Now I am wondering if my fuel pump is good, and I have an obstruction somewhere else.

Could a fuel pump look and sound like it is working, but not pushing enough fuel?

Could I have an issue with the pressure regulator? Does a new fuel pump assembly (with fuel cooler) come with a regulator? Do I need to buy that separately?

Thanks!

[chpthril]

step # 11: Not valid at all. You need to measure fuel pressure with the pump in the boat as its intended to function.

Could a fuel pump look and sound like it is working, but not pushing enough fuel?

Yes

Could I have an issue with the pressure regulator

Yes, but it would not prevent the engine from running.

Does a new fuel pump assembly (with fuel cooler) come with a regulator

Regulator is in the fuel rail. A faulty regulator can be diagnosed with a fuel pressure gauge.

[chuckhoenig]

Do you think I should put it back on and retest?

[chuckhoenig]

Fuel Pump Diagram 1.jpg

Could someone tell me what number 13 is? I thought it was a pressure regulator.