Big Block Oil Consumption
 

New to boating-bought a '94 Baja 24 Outlaw with a new Mercruiser 7.4 Magnum
EFI long block. It has straight exhaust and Bravo One out drive.

Boat runs perfect except for engine oil consumption. We have gone through
6+ quarts of Quicksilver 25W-40 in the first 20 hours. I have been very
careful to follow Merc's break-in quide: no long periods of idle, no
full-throttle starts. Every two-three hours, the dipstick reads a quart
low.

Now with 32 hours, a shop did a leak-down check. Four cylinders 10% which
is spec., three were about 25% and one was about 40%.

What do you recommend? What is normal oil consumption? Found about 1/2
quart in the bilge. The shop that installed the long block used an
aftermarket block with all Merc parts (crank, bearings, rings, pistons, cam
etc.)

Thanks in advance.

Jeff

The problem is with the straight exhaust. If you install some sort of
quieting system and throw away the ignition key, the oil consumption
will return to normal.

"Gene Kearns" wrote in message
...
On Wed, 13 Jul 2005 00:20:43 GMT, "Jeff M." wrote:

New to boating-bought a '94 Baja 24 Outlaw with a new Mercruiser 7.4
Magnum
EFI long block. It has straight exhaust and Bravo One out drive.

Boat runs perfect except for engine oil consumption. We have gone through
6+ quarts of Quicksilver 25W-40 in the first 20 hours. I have been very
careful to follow Merc's break-in quide: no long periods of idle, no
full-throttle starts. Every two-three hours, the dipstick reads a quart
low.

Now with 32 hours, a shop did a leak-down check. Four cylinders 10%
which
is spec., three were about 25% and one was about 40%.

What do you recommend? What is normal oil consumption? Found about 1/2
quart in the bilge. The shop that installed the long block used an
aftermarket block with all Merc parts (crank, bearings, rings, pistons,
cam
etc.)

Thanks in advance.

Jeff


I'd be looking at the shop that did the work to make good on this.
Without more to go on, it would appear that this engine has not
properly seated the rings and the 1/2 quart in the bilge was likely
blown out the breather or dipstick.

Whatever the cause.... the rebuild shop needs to be proactive in
getting things right before the warranty period evaporates... and you
end up holding another impressive overhaul bill....

--

_ ___c
\ _| \_
__\_| oooo \_____
~~~~|______________/ ~~~~~
~~~ ~~~~~~
~~~ ~~~~~ ~~~~~~~~~
~~~~ }((((o ~~~~~~ }{{{{o ~~~~~~~

Grady-White Gulfstream, out of Southport, NC.

http://myworkshop.idleplay.net/
Homepage*
http://www.thebayguide.com/rec.boats
Rec.boats at Lee Yeaton's Bayguide

Or it may want to run a quart low. Some engines seem to do this. I think
it is extra splashing that causes it.

25 & 40% is not good. All compression & leak down should be about the same.

"Jeff M." wrote in message
k.net...
New to boating-bought a '94 Baja 24 Outlaw with a new Mercruiser 7.4
Magnum EFI long block. It has straight exhaust and Bravo One out drive.

Boat runs perfect except for engine oil consumption. We have gone through
6+ quarts of Quicksilver 25W-40 in the first 20 hours. I have been very
careful to follow Merc's break-in quide: no long periods of idle, no
full-throttle starts. Every two-three hours, the dipstick reads a quart
low.

Now with 32 hours, a shop did a leak-down check. Four cylinders 10%
which is spec., three were about 25% and one was about 40%.

What do you recommend? What is normal oil consumption? Found about 1/2
quart in the bilge. The shop that installed the long block used an
aftermarket block with all Merc parts (crank, bearings, rings, pistons,
cam etc.)

Thanks in advance.

Jeff