Merc 496's that have not had serious issues during their lifetime, like serious overheat, loss of oil pressure or fuel pressure and supply issues with good maintenance and preventive maintenance should easily run over 1000 hrs. We have seen 496's with hard commercial service and good service and maintenance go to 2400hours plus.

My opinion is that most of the new closed cooling, efi engines that are properly cared for and properly stored and winterized will
re-write the current book on engine life expectations. The industry is building much more reliable marine power and todays boaters are the benefactors.

Take care of that "Puppy" and it will take care of you!

Best Regards,
Ray @ Raylar

502 EFIs-Arnesons
Cruise between 3400-3600=35mph depending on fuel load
WOT 4400=50mph if loaded light.
I only open it up occasionally to check WOT rpms. I enjoy boating alot more than wrenching so I take it easy. Port engine just turned past 1,000 hours on the clock. Still running good.

1994 27fever,509/425hp,bravo1 26lh.cruse speed between 45-50mph@3400rpm.

1993 35 LIGHTNING Usually 3000 rpms 48 or 50 mph according to which way the tide is running in the Del. River (HP 500"s)

until it breaks

I agree with Rays comment on modern engine tech.

My Ilmor 710 has been incredible.

I can run it wide open till I run out of room or fuel on a lake
- or until the length of my boat is the limitation on the ocean-
- then idle for an hour in a harbor, and or anything in between, any altitude lake, or outside temp and Ive never seen a single speck of soot on the transom.

Its as easy to maintain as a modern car engine which is to say you basically do very very little more than fluid changes.

Its not really "big" by blown big block standards, but its an all aluminum fuel injected 8.3 Litre V10 that makes 700 ponies.

light
simple
effective
reliable as an anvil

Pretty cool, by anyones standards

The engine tech is soo good I no longer worry about it at all and focus on keeping the drive alive.

Not sure how long it will run, but I hear one guy has like 600+ hours on a set now with regular maintenance. Im at 100 hours in 2 seasons.....well see.



Uncle Dave

1992 35 fountain 3200 - 3400 rpms 52 mph cruising
wot 5100 rpms 80 mph

The guy that now runs my old Parasail business just replaced his 496 with a new one because he was having some overheat issues with it.He had a little over 3ooo hours on it.Granted its not being ran much over 4000rpm very often but it runs a PTO for the winch off the motor that is drawing 40 to 50 hp when it it on 80 percent of the time when it is running.

Back in the day when i had the Parasail business and before we went to diesels it wasn't uncommon to get 3500 to 4000 hours out of the old 454 =330hp motors and they were ran in the 3500 to 4000 range quite a bit.

Don't over heat them and keep fresh oil in them and not run them above 4000 all the time and they will outlast you.

Cheapest insurance we had on the motors that we ran in salt water was new risers every year and new manifolds every 2 years.

Seeing how many issues the latest owner has had with the 496 if i was to go back into the business today i would put a carbed 330 in the boat.Cheap and easy to fix and cheap to replace.

Did the diesel route and the initial cost and than any parts and maintanance is 4 times that of the 330 gas and the little bit of fuel savings will never be recovered in 10 thousand hours and they really only go about 4000 hours anyways.

2400-2700 just under power valves=35to48 mph. Wot 5500-5600-103gps

454 mag, cruise at 4600rpm 150-160'f 50mph
wot which i run for 20min plus most of the time 5100rpm 165'f
66mph