2007 Merc 6.2L MPI barfing oil

[jumpjets]

The poker run last fall was a $250 entry fee. There were lots of super hi-dollar go fast boats, my rock stock Rinker. I won 3rd place for my hand, which equaled winning back my entry fee.

My motor is getting yanked out today. I purchased an ATK crate 383 long block marine engine. I'm going to swap all the accessories over, then drop in the new 383.

Once that's done, I'm going to perform an autopsy on my old 6.2L block. I want to visually find what failed on the motor, and I want to see what 3 years of raw salt water cooling has done to the block and heads. If the block is salvageable, I want to slowly build another 383 in my garage just for fun. That way, if I blow this new crate 383, I've got a spare ready to go.

 

[jumpjets]

Post 4

Whoops. Sorry for blowing you off and not addressing your post.

I forgot to mention: I put a new drive oil reservoir cap and bottle on it last fall. It was $50 from iboats.
After I have the new engine installed, I'll put a drive shower on the drive to keep it cool. Hopefully the new engine will run smoother and keep the drive from shaking and overheating.

I found these quotes over at "the hull truth", and they made me concerned:

"A hot bearing or gear can form an oil vapor bubble in the unit. Oil will then puke out of reservoir."

"I have a ton of experience with drives and rebuilds and I think it's an internal seal. Probably on top where driveshaft seals. Seal in that area will cause the symptoms you describe. You will probably find that when you pull drive a bunch of drive lube is in bellows. Leak there will build a lot of pressure."

https://www.thehulltruth.com/boating-forum/626998-bravo-3-gear-oil-overexpansion.html

 

[alldodge]

"A hot bearing or gear can form an oil vapor bubble in the unit. Oil will then puke out of reservoir."

Enough heat will cause expansion but not seeing one bearing causing a bubble in a drive. The B3 drive does produce more heat then others. A drive shower will help keep heat down, I'm using the Simrek.

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.

Two things, if you where on a hose, I would think need a new impeller

Oil coming up in 5 minutes with next to no load I would still say its the bottle. Said it was new (from iboats) but I would still say there is the issue. Take the bottle off and with a hand pump and gauge, apply 5 psi. If it holds give it a slight bit more, but not thinking more then 10 psi. Maybe Fun Times would have some better insight.

The Bravo drive will have air in the top after regular filling which is normal. With in the first few hours the air will go to the bottle and lube will lower. To have little to no air exchange is after filling, lay drive on its side, then remove top plug and pour lube until full.

 

[Scott Danforth]

The poker run last fall was a $250 entry fee. There were lots of super hi-dollar go fast boats, my rock stock Rinker. I won 3rd place for my hand, which equaled winning back my entry fee.

My motor is getting yanked out today. I purchased an ATK crate 383 long block marine engine. I'm going to swap all the accessories over, then drop in the new 383.

Once that's done, I'm going to perform an autopsy on my old 6.2L block. I want to visually find what failed on the motor, and I want to see what 3 years of raw salt water cooling has done to the block and heads. If the block is salvageable, I want to slowly build another 383 in my garage just for fun. That way, if I blow this new crate 383, I've got a spare ready to go.

which cooling system? if you have the single point drain, look at each of the lines. most of them will be plugged.

 

[jumpjets]

which cooling system? if you have the single point drain, look at each of the lines. most of them will be plugged.

I'll need to post pics of the engine for you. I'm assuming I have a 3-point drain. There is one blue plug on a ball shaped gizmo on the front of the engine, and two blue plugs on the sea pump.

I will receive the engine in a day or two. I'm thinking of starting a new thread to show the build process.

One quick question: I intend to use the stock merc MPI fuel injection system and computer. The merc 6.2L was rated at 320hp. This new engine is rated at 345hp, and it's 6cubic inches larger. I'm curious if I need to get the computer re-tuned for the extra power, or if the stock mercury program can run the engine without causing it to go lean.

 

[Scott Danforth]

The 6 cubic inches wont mater

350hp at the flywheel is 320hp at the prop.

Unless you build your own motor, your new motor is same as the old motor

 

[Oldnbold]

After reading the results of hrs of high rpm running,!im glad I get antsy anytime my 7.4l turns over 3500 rpms for more than 5 mins. I start hearing phantom noises like rods coming through the block...lol.

 

[achris]

After reading the results of hrs of high rpm running,!im glad I get antsy anytime my 7.4l turns over 3500 rpms for more than 5 mins. I start hearing phantom noises like rods coming through the block...lol.

NEVER running at engine at WOT is just as bad as running at WOT for hours on end. As engine speed increases, the pistons reach a little higher in their bores, and if a ridge has developed due to the pistons never having gone up that far, the first time you do, the rings hit those ridges and break.

It's a good idea to run at WOT for 5 to 10 minutes, if the weather is suitable, every now and again. As long as you're not over-propped, nothing bad will happen.

Chris......

 

[jumpjets]

Haven't checked in for a while with respect to this project. Here are some casual observations:

-The new engine is running very well. It seems to have more power than the old engine. I now hit the rev limited of 5200 RPM at about 2/3 throttle. I think I'm going to switch from a 24P prop to a 26P and see what that does.

-I installed a wideband O2 gauge in the exhaust. I was worried that with a bigger cam and a few more cubes, the engine would run lean. Quite the opposite. The Merc computer is keeping the engine fat, with about 13:1 AFR regardless of RPM and throttle setting.

-My old drive continued to barf oil. Then I accidentally hit a bunch of rocks and destroyed it. I installed a lightly used B3 drive with new props, and I added a drive shower. As I was putting it back together the oil reservoir o-ring got distorted. Now I have a new drive, new engine, new drive shower, that still barfs drive oil. Time for another new oil cap.

-Getting a local shop to install the engine was a nightmare. Quotes varied from $600 to $10,000. Once I selected a shop, it took them 6 weeks to install the engine. Every single day they said "it'll be done tomorrow". Lesson learned: It would have been cheaper and faster to buy my own gantry crane from harbor freight and swap the engine myself.

-The oil dipstick from my stock merc 6.2L was wrong!! It indicated full with 3.75 quarts of oil. I re-etched the dipstick to show 5 quarts of oil. The new engine has a 5 quart pan, just like the stock merc.

-A little bit of oi in the bilge makes it look like a catastrophic oil leak.

 

[alldodge]

13 isn't fat from my findings, its on the edge of starting to go lean. Have been discussing my build prior and while I weight twice what you do, this is what Artic Friends OSO said about AFR and MAP (vacuum)

Vacuum and how it applies: each 10 map or kpa is 3.3" of vacuum. So cruising "easy" if your at 70 map, its about 10" of vacuum, you can tune the motor around 13.5 in the 1600 to 2800 range IF your at 70 map, ie, low load, when your in the 80 map range, 12.8 to 13.2 or so is ususlly fine up to about 3400/3600. When you start hitting 90 map, i like to see mid 12's, when you start getting into 95+map AND near the tq peak, usually 3800 to 4200 or slightly higher, mid 12's , even 12.2 to 12.5 once your hitting 4400/4600 on up.
i give the idle whatever it likes, ive seen quite a few motors that didnt like 13+to 14 at idle even though thats what you would think of as "normal". You still need to take a look at the plugs too if you choose to lean out around 2800 to 3400, especially 7/8