2007 Merc 6.2L MPI barfing oil

[jumpjets]

My 2007 Merc 6.2L MPI / BRAVO III drivetrain functioned flawlessly for many years. After flogging it in a poker run last fall, it has a spectrum of issues. Any pointers are greatly appreciated.

1. The drive oil reservoir is overflowing after running the boat for ~1 hour or more on plane. I've checked the drive, and it doesn't water in it. The drive reservoir will barf oil from the cap. Once I stop and shutoff the engine, the drive reservoir looks low on oil. The oil is clearly dripping from the reservoir cap down into the bilge.

2. The engine has a ton of blow-by. I installed new PCV valves and an oil catch can this winter. The catch can has insufficient flow capability, and it's causing oil to flow up the dipstick tube, and steadily flow out of the dipstick hole. I did a compression check, and everything was around 160psi, which seemed OK.

3. There is a rapid but inconsistent beeping tone coming from the engine.I'm guessing the guardian system is trying to warn me of a malfunction. I don't have a code scanner to check it.

The boat had none of these problems until I ran it at 5000 rpm for 4 straight hours.

 

[achris]

...The boat had none of these problems until I ran it at 5000 rpm for 4 straight hours.

And likely you never pushed it up anywhere near that before, and given 2007, I'm guessing maybe 600 hours?

You're probably pushed the rings up passed the ridge at the top of the bore, and broken the lot of them. Pull engine and rebuild.

Oil in the reservoir. Those cracked rings are causing engine harmonics and the oil is literally being thrown out of the bottle. Pull engine and rebuild.

 

[Rick Stephens]

I think I remember your first post on this. Seems to me you have little choice but to pull the motor and go through it, as Chris suggested. I'd be worried about the drive as well. Having the top half up and out of the water for 5 hours is hard on the upper gear case.

 

[alldodge]

1. The drive oil reservoir is overflowing after running the boat for ~1 hour or more on plane. I've checked the drive, and it doesn't water in it. The drive reservoir will barf oil from the cap. Once I stop and shutoff the engine, the drive reservoir looks low on oil. The oil is clearly dripping from the reservoir cap down into the bilge.

The drive reservoir has a one way valve in the cap. The valve when working correctly allows air in but not out. When the lube oil starts blowing out by the cap, the valve has gone bad. Need a new cap or complete bottle

2 and 3

Agree rebuild motor will take care of 2, and this will probably fix 3

 

[jumpjets]

Hey guys, thanks for the quick responses. Yes, I did post about this last fall.
Just to get some amplifying data, I did a couple extra (silly) tests.

1. I put a rubber glove over my PCV hoses. At idle, the glove inflated from empty to the size of my hand in 5 seconds.
2. I ran the engine at 2500 RPM with the drive engaged and the prop spinning. The drive reservoir bottle slowly filled up over a period of 5 minutes, and then overflowed. As soon as I shut down the engine, the drive oil level slowly decreased to it's original level.

I'll guess I'll start looking into pulling the motor!!!

 

[GA_Boater]

At idle, the glove inflated from empty to the size of my hand in 5 seconds.

You have no rings left. Surprised it started and ran for 5 seconds.

Do a compression test, one or more cylinders will be zero.

 

[jumpjets]

You have no rings left. Surprised it started and ran for 5 seconds.

Do a compression test, one or more cylinders will be zero.

This whole situation is surprising to me! It starts and runs fine. I took it out on the river for a few hours today. It runs, planes, etc, just fine. I did a compression test on the port side cylinder bank. All cylinders were 160psi. I didn't test the other side yet though. The motor isn't smoking or anything when I run it on muffs on the trailer.

 

[GA_Boater]

It starts and runs just fine.

All the while it's puking it's life blood out of the dipstick. This isn't an old British motorcycle. You must like wiping up oil.

Check the other 4 cylinders for compression. Make that all 8!

 

[Lou C]

And if you want to use your boat that way a stock GM engine will never last. You’d need a race build if you want a chance of it lasting. A 4 stroke outboard or DI 2 stroke can be run like that but for sure not a stock inboard...

 

[Scott Danforth]

If you want a poker run boat, you will have to build the motor to suit. Factory 6.2 is a great all-around motor, but it is not a long distance high RPM motor

 

[jumpjets]

I told my girlfriend last fall: "if my motor blows during this race, it'll still be worth it"

Famous last words. I was hoping that I'd know the motor failed at the end of last season, not at the beginning of this season. whoops! $5000 mistake.

 

[Scott Danforth]

You can build a good motor withe your block and heads for under $2500

 

[jumpjets]

Since my outdrive is barfing oil as well, what should I check with it? What are common failures with a Bravo III drive? Is it possible that a bearing seized up, and it's overheating the top of the drive?

 

[jumpjets]

You can build a good motor withe your block and heads for under $2500

I'm thinking about buying a crate long block just to get the boat back on the water quickly. Then, I can slowly rebuild my busted engine. I've wanted to build another engine for quite a while, but I don't want to do it this summer. I'll save it until this winter.

I'm honestly more concerned about my bravo III drive at this point. Those things look to be more expensive than the engines they're bolted up to.

 

[Scott Danforth]

crate longblock is $4200 for a duplicate of what you have.

However if you work with your local machine shop, you can build what you want about as fast as you can buy the longblock.

 

[alldodge]

Since my outdrive is barfing oil as well, what should I check with it? What are common failures with a Bravo III drive? Is it possible that a bearing seized up, and it's overheating the top of the drive?

Post 4

 

[achris]

I gotta ask. What is a poker run? And how is a boat involved, at WOT for 4 hours straight. :facepalm:

I thought poker was a card game of very little skill, just the ability to BS your fellow players. :noidea:

Chris........

 

[JASinIL2006]

A poker run is a contest is where you zoom from one location to the next in your boat. At each location, you get a playing card, and after you have visited all the locations (and picked up all your cards), you make the best poker hand you can with those cards. At least that's how I've seen it done.

 

[Scott Danforth]

to add to above...... Normally its go-fast Sausage Boats with multiple engines built to go WOT for hours. its an opportunity to burn a few thousand $ worth of fuel in a very short time. Many times the entry fee is about $750 to $1000 alone, then you have fuel and maintenance.

Typical poker runs down here in Florida are from Miami to Key West, or Key West to Tampa.

https://flpowerboat.com/project/key-west-offshore-poker-run/

 

[Rick Stephens]

We used to do $25 entry poker rides with horses. All over the mountain with limited clues where the next card was to be gotten. In the Army you'd do them with a map and compass directions. Fastest unit getting a pass on duties or to town.