Lost oil pressure during 1st cruise-gctid374602

[Guest]

Was out for 1st cruise on our 1st boat on Sunday. Boat is 1999 Bayliner Rendezvous with 5.7L Carbed Mercruiser V8 and Bravo 3 outdrive. I changed all of the fluids, filters, seals in the outdrive, water impeller, plugs, wires, cap, and rotor on the engine. Left port and was cruising for about 30-45 minutes at 3400RPM, oil pressure at 50psi, and speed was varying between 29 and 32 MPH depending on water smoothness and wind direction. RPM and oil pressure remaining consistent with no variance. I felt a "pop" go though the hull while the engine seemed to hesitate briefly. I was watching the gauges and all was unchanged when the oil pressure dropped to 0psi and the alarm went off. The engine was still running normally, so I throttled back to neutral and shut down the engine. Once the boat slowed to a rest, I opened the dog house to take a look at the engine. No leaks, bilge was dry, no smoke or anything looking amiss. Tried to restart the engine, the starter turned normally but engine would not catch. Check the carb, and was getting fuel when the throttle was operated. Pulled main coil wire into distributor and checked distributor end of wire with no spark.

Got tow back to port. Have not had the chance to check yet, but my gut feeling is that I lost the roll pin that locks the cam gear onto the distributor shaft.

When I get the chance, will go pop distributor cap and check to see if I can turn the rotor by hand. If I can, then that is the culprit.

Anyone else have a similar experience? If this is what the cause is, then I will add some spare roll pins to my onboard toolkit/spare parts bag.

[Guest]

Good guess- though I think a roll pin shearing wouldn't cause a 'pop' as you described.

[Guest]

Put it this way, that's what I'm HOPING it is. Not sure how to exactly describe it, but I felt something when the engine seemed to slightly hesitate or tighten up right before I lost oil pressure.

I will probably pull distributor out to check that gear, if it's just a pin - I want to make sure the gear isn't chewed up with metal filings in the oil. Anything else that would cause the same issues will probably require pulling the whole engine out. Not really what I wanted to happen on 1st cruise after putting that much work into it beforehand.

Is cruising at 3400RPM on a 5.7L too much or 50PSI oil pressure too high? I won't say that I'm a boat mechanic, but I do know my around engines and such. Don't have a lot of boating experience, but not new either - been riding in them for a while without piloting.

[iceclimber]

When you changed the oil, did you see any sludge? I don't know that 50psi is too high, if it is actually reading correctly. Nah, 3400 is not too high. Did you say you are not getting a spark? Don't be afraid to take it to a marine mechanic. He might spot it in seconds.

[Guest]

Last season I have started having erratic oil pressure readings. Sometimes it would drop to 0 then pickup again, turned out it was corroded pressure sender wire. It did freak me out, however I did not hear an alarm. If I understand correctly there are two senders, one is oil pressure sensor for the gauge and the other is ON/OFF type that sets off buzzer if the oil pressure is below minimal.

Before taking apart the engine, I would take old oil filter and punch the hole in it to see if oil is actually flowing when someone bumps the engine ignition. Have plenty of absorbent pads in the bilge and small bucket to collect the oil.

[2850Bounty]

TheBaalmans wrote:
I felt a "pop" go though the hull while the engine seemed to hesitate briefly. I was watching the gauges and all was unchanged when the oil pressure dropped to 0psi and the alarm went off. ** The engine was still running normally,

Got tow back to port. Have not had the chance to check yet, but my gut feeling is that I lost the roll pin that locks the cam gear onto the distributor shaft.

When I get the chance, will go pop distributor cap and check to see if I can turn the rotor by hand. If I can, then that is the culprit.

Anyone else have a similar experience? If this is what the cause is, then I will add some spare roll pins to my onboard toolkit/spare parts bag.

The camshaft gear is the "drive" gear, and the distributor gear is the "driven" gear.

If the spring pin sheared, you'd not only loose the oil pump drive, but you'd also loose distributor shaft rotation... which means that ** above would not have occured. The engine would have shut down immediately.

Look at your engine harness connections, and in particular, the wiring for the oil pressure sender AND the low oil pressure switch. This may be nothing more than an electrical issue.

If you end up testing for oil pressure, rather than punching a hole in the oil filter, install a mechanical oil pressure gauge into the oil galley port where the current oil pressure sender is installed. Disable the ignition, and crank the engine over, and observe the gauge.

With the ignition still disabled, pull the distributor cap like you mentioned, and watch for rotation at the rotor.

If the roll pin/spring pin had sheared off, you're going to see zero oil pressure and zero distributor shaft rotation.

It would be very rare to see that one of these pins has sheared, IMO.

.

[Guest]

2850Bounty wrote:
If the spring pin sheared, you'd not only loose the oil pump drive, but you'd also loose distributor shaft rotation... which means that ** above would not have occured. The engine would have shut down immediately.

.

I agree, but after speaking with my wife last night and the family that was on board with us, they claim that the engine shut off the split second the alarm went off. It's possible that my sense of time is altered by being in "crisis" mode and that me pulling back on the throttle coincided with the engine shutting down on it's own. The only way to be sure is to get on board and start diagnosing, will start with checking distributor rotation. If it is just an electrical issue with oil pressure sender or switch - that would not cause the loss of spark. Unless there might be a grounding issue? Did not think to check for voltage at the coil while on the water.

Will check all the connections as well, when I was servicing the boat I found the charging wire on the alternator was loose and corroded. I did clean it up and solder on a new connector. Voltmeter on dash was reading 14 volts before incident. I also checked after made the repair that was getting the same voltage with a multimeter as the dash voltmeter was reading. After the incident while on the water I did check the battery connections, was reading 12.4 volts across all battery connections and made sure all connections on the back of the alternator were tight.

When I changed the fluids, the engine oil was dark and very dirty, but not sludgy. Same with drive oil, dark but with a slight green tint. Neither had any sign of milkiness.

I do have a friend that is a boat mechanic, he helped me with doing all the service on the boat. Hoping he can come by this weekend and take a look, will try to go check distributor rotation before then if weather and work permit.

[Guest]

TheBaalmans wrote:
Was out for 1st cruise on our 1st boat on Sunday. Boat is 1999 Bayliner Rendezvous with 5.7L Carbed Mercruiser V8 and Bravo 3 outdrive. I changed all of the fluids, filters, seals in the outdrive, water impeller, plugs, wires, cap, and rotor on the engine. Left port and was cruising for about 30-45 minutes at 3400RPM, oil pressure at 50psi, and speed was varying between 29 and 32 MPH depending on water smoothness and wind direction. RPM and oil pressure remaining consistent with no variance. I felt a "pop" go though the hull while the engine seemed to hesitate briefly. I was watching the gauges and all was unchanged when the oil pressure dropped to 0psi and the alarm went off. The engine was still running normally, so I throttled back to neutral and shut down the engine. Once the boat slowed to a rest, I opened the dog house to take a look at the engine. No leaks, bilge was dry, no smoke or anything looking amiss. Tried to restart the engine, the starter turned normally but engine would not catch. Check the carb, and was getting fuel when the throttle was operated. Pulled main coil wire into distributor and checked distributor end of wire with no spark.

Got tow back to port. Have not had the chance to check yet, but my gut feeling is that I lost the roll pin that locks the cam gear onto the distributor shaft.

When I get the chance, will go pop distributor cap and check to see if I can turn the rotor by hand. If I can, then that is the culprit.

Anyone else have a similar experience? If this is what the cause is, then I will add some spare roll pins to my onboard toolkit/spare parts bag.

I would be incline to remove the distributor gently, rather than turn it.

If the gear is disconnected at the end of the shaft you want it to come out with the distributor. so in my opinion don't do anything that may cause it to fall off.

With the distributor off you can check the oil pump with a long screwdriver but remember where the slot is facing and put it back to that position.

You will find your engine at this link:

http://www.mercruiserparts.com/selectModels3.asp?type_id=8

Attached files http://baylinerownersclub.org/media/...uter.jpg[/img]

[Guest]

I'm thinking the coil or ign module died on you and the momentum carried the boat futher so maybe it felt like you were still running as you throttled back.

Is this the thunderbolt ign setup on this?

[Guest]

first off ...50 psi is about normal...engine oil pressure can be as high as 65 psi before you get bearing wash...so..I'd rule out oil pressure being too high....now to me it definitely sounds like it could be ignition or module related.....let us know what you find out..one way to check before you pull the distributor is to take the cap off and have someone turn the engine over a few times....if it turns...you don't have a gear problem....if it just sits there....you definitely have a gear problem....

:arr arr

[Guest]

seapuppy wrote:
first off ...50 psi is about normal...engine oil pressure can be as high as 65 psi before you get bearing wash...so..I'd rule out oil pressure being too high....now to me it definitely sounds like it could be ignition or module related.....let us know what you find out..one way to check before you pull the distributor is to take the cap off and have someone turn the engine over a few times....if it turns...you don't have a gear problem....if it just sits there....you definitely have a gear problem....

:arr arr

I wouldn't do that, if the gear on the bottom of the distributor comes loose it will fall into the bottom of the engine when you pull the distributor. That means removing the engine. Trying to turn the rotor will likely show a lot of resistance even if the pin is sheared.

The gear will turn if you turn the motor.

Removing the distributor for a check is a no brainer just mark where the rotor and distributor are aligned. and don't turn the motor with it removed.

[Guest]

I dont have the oil pressure alarm, but as I understand it, the oil pressure alarm will cut the ignition, and will need to be reset before spark is restored, no? this may be why there is no spark?

Could be as simple as a plugged oil passage and a false reading of no oil pressure, causing the alarm, causing the ignition to cut off.

But then, I dont have this alarm function, so I could be way off. Just a thought.

[Guest]

It wasn't the distributor or gear, they are all fine. When I start cranking the engine for a bit, I get oil pressure - so the pump is fine. Started following the manual for diagnostics and I believe I have a bad distributor pickup module. When I pulled the module out to inspect, there was a fair amount of corrosion on the solder and wires in it. I have 11V at the coil and 11V going into the pickup module, but 7V coming out of the module and it does not fluctuate as the engine turns over and the rotor spins though the pickup. I know I should have 12V at coil and going into distributor, so will follow those wires and make sure I have a good connection. Checked the batteries and have 12.5V at them.

For those wondering, it is the Thunderbolt V ignition system.

[Guest]

dpoelstra wrote:
I dont have the oil pressure alarm, but as I understand it, the oil pressure alarm will cut the ignition, and will need to be reset before spark is restored, no? this may be why there is no spark?

Could be as simple as a plugged oil passage and a false reading of no oil pressure, causing the alarm, causing the ignition to cut off.

But then, I dont have this alarm function, so I could be way off. Just a thought.

its the buzzing right before the engine turns over- loud as hell.. u cant miss it

[Chief_Alen]

If the pickup is shot consider yourself lucky it's not the ecm. If you do conclude the ecm went then post back do not buy one. There are other alternatives.

There is a reason i write this..i have seen many ecm's go and it is just not worth replacing them when there are so many better alternatives.