Merc 700 sci question...
 

I was at the boat show the other day and was looking at 38 footers (Formula, Fountain and Donzi) with twin 700 sci motors and NXT drives. The sales people were telling me about the performance advantages but also explained that the motors would need a complete rebuild after 150 hours. Now I am new to this level of performance (I have a 27' ft., 2000 Checkmate with a single 454) but read a whole bunch of specs and info on this motor. Nowhere else did it say anything about such a short life span.

Can someone enlighten me... If I bust a nut to get into one of these monsters will I be rebuilding in 2 to 3 seasons?

Probably wont matter cause I gotta have one!!! But just curious.

Thanks.

Brian

Posting this on the General Boating section will get you 10 times the response...

The 700 is nothing more than a 502 with an intercooled Whipple. Not a radical setup by any definition. It should be good for at least twice or maybe three times that. If you ran it at maximum rpm in race conditions, then maybe. Merc is the most expensive out there and very high quality. They're also pretty conservative on things. It's hard to have that many customers and continue to sell at those prices if their stuff wasn't holding together and delivering a good lifespan.

The rebuild interval number sounds like the 1075/1200 engine's. I think I saw a press release about Merc's rebuild program for that motor that quoted that 150 hr. number

MAINTENANCE
52
Mercury Marine recommends that you have the dealer do periodic
maintenance checks on your power package. Have them winterize
it in the fall and service it before the boating season. This will
reduce the possibility of any problems occurring during your
boating season when you want trouble-free boating pleasure.
IMPORTANT: Refer to the Maintenance Charts (on following
pages) for a complete listing of all scheduled maintenance to be
performed. Some listings can be done by the owner/operator,
while others should be performed by an authorized Mercury
Marine dealer. Before attempting maintenance or repair
procedures not covered in this manual, Mercury Marine
recommends purchasing a Mercury Marine Service Manual.
Maintenance Charts
NOTE: The following maintenance charts should be used as a
guideline. Depending on the type of boat, optional equipment, the
application and/or conditions of use, it may be required that the
maintenance intervals be modified. Work closely with your
authorized Mercury Marine dealer to develop a specific
maintenance schedule designed for your application.
ENGINE MAINTENANCE SCHEDULE
Interval Task
After first 25 hours of operation Change transmission fluid
Check prior to every use and every 3
hours of operation
Engine Crankcase Oil - Check level
Seawater Filter - Check for debris or
leakage
Power Steering Fluid - Check level
Transmission Fluid - Check level
Supercharger - Check oil level in
sight-glass
Fuel Pump Sight Tube - Ensure that
no fuel is present. Vapor or
condensation is acceptable
After every use in salty, brackish, or
mineral-laden water
Flush the seawater section of the
cooling system
MAINTENANCE
53
Interval Task
Every 25 hours of operation or once
every 30 days, whichever occurs first
Battery - Check water level and
inspect for corrosion or damage
Inspect external water pickups -
Check for marine growth or debris
Sea Pump/Fuel Pump - Check the oil
level and inspect for fuel
contamination
Engine Oil and Filter - Change
Saltwater use: Every 50 hours of
operation or 60 days, whichever occurs
first
Power Package Exterior Surfaces -
Spray with rust preventive
Every 50 hours or once a year,
whichever occurs first
Perform all 25 hour maintenance
items
Serpentine and Supercharger Belts -
Inspect condition and check tension
Cooling System Hoses and Clamps -
Inspect for damage and deterioration.
Check clamps for tightness
Electrical System - Check for loose or
damaged wiring
Continuity Circuit - Check components
for loose connections, broken or
frayed wires
Shift and Throttle Cable and Linkage -
Lubricate and inspect for loose,
damaged or missing parts
Engine Exhaust System - Inspect for
damage, deterioration and
restrictions. Check clamps for
tightness
Water Separator Filter - Inspect (If
Installed on boat)
Engine Driveshaft and Slip Yoke -
Lubricate (drive-line models)
Freshwater use: Twice a year Power Package Exterior Surfaces -
Spray with rust preventative
MAINTENANCE
54
Interval Task
Every 100 hours of operation or once a
year, whichever occurs first
Perform all 25 hour and 50 hour
maintenance items
Supercharger - Change oil
Power Package Exterior Surfaces -
Clean and paint
Engine Cylinder Compression - Check
Engine and Power Steering Oil
Coolers - Clean the seawater sections
Positive Crankcase Ventilation (PCV)
Valve - Replace
Flame Arrestor and Crankcase
Ventilation Hose - Inspect, clean or
replace
Engine Alignment - Check
Exhaust - Check for signs of water
leakage
Exhaust System Internal and External
Shutters - Inspect
Change transmission fluid
Every 100 hours of operation or
recommissioning after storage
Peform 25, 50, and 100 hour
maintenance items
Fuel filters - Replace
Every 100 hours of operation or once a
season or whenever insufficient
seawater flow is suspected causing the
operating temperature to exceed normal
Seawater Pick-up Pump -
Disassemble and inspect
Every 200 hours of operation
Peform 25, 50, and 100 hour
maintenance items
Ignition System - Clean and inspect
condition. Check electrode gap or
replace spark plugs as needed
Change power steering system filter
(s)
Every 5 years Flush the closed cooling system and
refresh coolant
MAINTENANCE
55
NXT¹ DRIVE MAINTENANCE SCHEDULE
Interval Task
Check prior to use and every 3 hours
of operation.
Drive, Transom, and Propeller - Inspect.
Lower Gear Housing Oil - Check level.
Power Trim Pump Oil - Check level and
for any water contamination. Replace if
necessary.
Anodes - Inspect for erosion.
Gear Housing Water Pickups - Check for
marine growth or debris.
Initial break-in at 25 hours. Lower Gear Housing Oil - Change
Every 25 hours of operation or every
90 days, whichever occurs first.
Tie-bar Mounting Bracket Nuts - Inspect
and tighten to specifications as needed.
Propeller Shaft - Lubricate.
Propeller Nut - Retighten.
Anodes - Inspect for erosion.
Sterndrive - Inspect, clean, and spray with
rust preventative.
Every 50 hours of operation.
Perform 25 Hour Maintenance Items.
Sterndrive Unit Input Splines (Internal
and External) - Lubricate with Optimol
Paste White T Grease.
Drive Mounting Nuts - Tighten to
136 Nm (100 lb. ft.)
Drive Input Shaft - Lubricate.
Steering System - Inspect for loose,
damaged or missing parts. Lubricate the
steering cylinder pivot points.
Transom Gimbal Housing Assembly
Swivel Shaft and Gimbal Bearing -
Lubricate.
Every 100 hours of operation or
every 120 days, whichever occurs
first.
Peform 25 and 50 Hour Maintenance
Items.
Drive Unit Bellows and Clamps - Inspect.
Inspect all rotating and reciprocating
components for wear. Replace the
components as needed.
MAINTENANCE
56
Interval Task
Every 100 hours of operation
Lower Gear Housing Oil - Change
Transom Input Shaft Bearing Housing -
Change the oil.
Every 200 hours of operation or once
a year, whichever occurs first.
Peform 25, 50, and 100 Hour
Maintenance Items.
Engine Alignment - Check.
Propeller Shaft Bearing - Inspect by
measuring shaft deflection.
Every rebuild Lower Gear Housing - Oil and filter
change
Checking Fluid Levels
CHECKING CRANKCASE OIL
IMPORTANT: Check the engine crankcase oil at the intervals
specified in the Maintenance Chart.
NOTE: Oil consumption is greatly dependant on engine speed.
Consumption is highest at wide-open-throttle and decreases
substantially as engine speed is reduced. It is common for big
block, high-performance engines to use up to one quart of oil in
one to five hours, if the engine is operated continuously at the
upper end of the RPM range.
1. Stop the engine.
2. Allow approximately five minutes for the oil to drain into the oil
pan. The boat must be at rest in the water or at the
approximate angle that it would be if setting in the water.
3. Remove the dipstick, wipe it clean, and re-install it all the way
into the dipstick tube.
4. Remove the dipstick and check the oil level. The oil level must
be between the "OK RANGE" and the "ADD" marks.
5. If the oil level is at or below the "ADD" mark, remove the oil
filler cap (port or starboard). Add enough oil to bring the level
into the "OK RANGE" on the dipstick. Do not overfill.

Plugs at 200 hours. My guess is the engine rebuilds are more hours than that. ;)

Thanks for the notes guys.... I did notice after I posted that this should have been in the General thread. Thanks for pasting all of that Nascat... I did see those charts when I was looking for info on the net. Doesn't seem much different from what I do now... only on a much bigger scale. I have almost 1000 hours on my 454 in salt water and usually stay pretty much on top of things myself. I just thought it would be a little outrageous to ask me to spend upwards of 1/2 a mil on a monster boat that would need to have the power plants pulled in less than 3 years time. I know my way around a big block and only some of the new tecnological advances may set me back a bit. This will also be my first step into the world of super-charged big blocks.

Anyway... thanks again for the help. You may see this posted in General again just to hear what some others have to say.

Be well and keep warm this winter.

Brian

That # doesn't sound right. The Merc Racing 600sci calls for a rebuild at 400 hours. Talking with Scott, the Merc Racing rep. He told me the test motors were run full out. And the average life span for the 600 was around 700 hours ( pretty respectable). So the warranty is for 400 hours or a year. Merc does stand behind their motors. The 150 hours seems a little low.

I would have to agree that number is very low. You may have to do the top ends at 200-300hrs. Full rebuild I would say 400 to as high as 800hrs. Depends how hard you run it.