502 mpi hours before refresh?
 

Boat is all stock with around 500 hours on it. Always maintained, runs great. Just wondering when these black motors usually need to be freshened up? Thanks for the input.
1997 Fever 27

It's time

If you believe this here is your answer:

http://www.offshoreonly.com/forums/f...you-run-3.html



Post #22 from PARASAIL341 and #25 from flat rate

Crossing my fingers lol!

I have a good friend with 1000hrs on the 454 black motor in his 27 fountain, so I would say you have quite a while! Btw he has lost some performance at this point, but it still runs good. It all depends on how it is maintained.

How much performance is it a gutless wonder now? Lol

You're kidding right?

Change the oil regularly, don't let them overheat and you can easily see upwards of 1000 hours with NORMAL use,,,,,,,, start the motor and run WOT all day will obviously change things !!!!

Run it until it's broke, if that ever happens.

A rotted and/ or leaking exhaust will break that motor before it breaks itself.

Any idea on how much it changes things?! Just trying to get a feel for the abuse I can dish out myself as a new owner as I have no experience... lol


I will be replacing my exhaust with Stainless Marines before it touches the water again for this reason!

This was a 365HP 454 in a 92 straight bottom fever. The boat ran about 65mph with low hours and now runs about 60 even. I believe this is a flat tappet cam engine also. The newer engines are roller and should hold up even better.

That's good info thanks!

Don't be afraid to run your boat,,,,, but to pin it wide open with no regard for oil temp ( which you may not even have a gauge for ) and old / questionable quality oil is a recipe for failure.

The most common high hour failures engine I see come through the shop is blown head gaskets,,,, and normally after an overheat. I had a 38 Special with stock 502's and 1100 hours on it and it only dies because the owner refused to repair the old VST fuel system.

Run a good oil, Castrol HD 40, Valvoline VR1 40 ,,,, Rotella makes a great high Zinc content oil, ETC,,,,,,,,, keep it clean and enjoy !!!

His being a '97 it likely is a VST set up (as is mine). Would you care to expand on your comment concerning VST? Trying to learn something here. Thanks.

VST = Very Stupid Thing. Ha !

Like others said as long as it has been maintained well you should be good to go. My '95 has 700 right now and I'm not planning on a rebuild anytime soon (I hope lol). But the previous owner had all maint done at the Fountain dealer by the same tech it's entire life until I purchased it so I know it has had a good past.

All you high miler's chime back in when you spin some bearings due to low oil pressure cuz the oil pump is wore out or worse yet a window in the side of the block, my engines also ran great and when I pulled my 502 MPI's apart at 600 hours, they were wore slick, I could shoot carb cleaner into the intake runners and watch it come out the valve seat same with the exhaust. Over a period of years you don't really notice a big decline in power because its gradual. So good luck, run r till she blow's

I have oil gauges and watch them for sure! I plan on trying the VR1 when I change oil next also heard good things about it but not sure what weight is best.



Yes please! Mine is a 95 and if there is some upgrade to help it live longer I'm all in!! DO TELL!

id redue the heads .. upper rebuild ..in the off season .. im guessing theese 1000 hrs are fresh water motors .. thats alot of hrs .. i wonder why people always stay away from boats with 500 plus hrs on them . at least everyone says they arnt worth as much with such hrs on them ... sorry for disagreeing .. im guessing theres few with that many hrs . compared to the many failures well below that mark ... leakdown ...

Friend here (Oneanddone) has over 600 hours on blown 454s. 1991 boat and motors. Bottom ends have never been out of the boat. Top ends done in the past but stock bottom ends. Boat runs like a dream. Mixture of fresh and salt it's whole life.

Vst is a vapor locking device merc put on to the hours down. Jk
Do a search, many many threads.

here is my 2cents on your delima.I have a 27fever also....its even a signature series like yours.its a 94.502mpi.it has the vst injection system.when I bought the boat it had 383hrs and it ran great for 2yrs.i started having fuel related problems with the vst.I know very little about fuel injection.but I do know how to tune a carb.long story short.when the motor did take a chit @437hrs .I rebuilt it and had the injectors flowed and cleaned.i also had the entire fuel system serviced.after all that I still had problems with the vst vapor locking.i know this has been a sorce of problems for a lot of boaters.rather than pay someone to work on it I did what know.i removed the injection,and installed a carb.did I lose any performance,no.did I take a hit on gas consumption,yep.a 1/2 gal less.dont get me wrong.i would have rather kept the injection,but wasn't ready to pay a marine shop to do the work,or learn how to work on injection.after all,i had plenty of manafolds and carbs left over from my drag racing days.so,this was a easy choise for me.i agree with others on here.aleast pull the heads off or leak down the motor.think about.you have a performance boat.people buy a permormance for one reason,,,,,thats to run fast,run hard.i can say this.when I did tear down the motor @437hrs.it need it.also.if you have injection.you are liminted to what you can do as far as engine mods go.i know a lot of people on here will disagree with that statement.but it came from mercury.hope this helps.

^ Curious why your engine blew?

high pressure pump got weak and leaned the motor out.put two holes in the pistons.

Think I'm gonna do a compression and leakdown test after this season. My suspicion is it should be freshened atleast. Interested in any experience with some mild mods on these motors such as a cam swap. I want to keep it EFI for sure though.

725hrs. On my 454's /blowers did head/valve work at 600 , cams were worn replaced with roller. Just freshend the blowers going for 1000. Oil pressure is great and don't use any oil ....

Did you add the blowers to your stock engine after the fact or were they built that way?

Diamond Dave. Bills engines were stock 454/425s that had the 250s added on top.

Do you happen to know if they had a good amount of hours on them already when he added them?

Not sure. He is the third owner of the boat. He has talked to last owner and got a good bit of history. I'll tell him to check it again. A bbc bottom end is extremely strong and most failures are catostrophic not wear. Either from improper tuning or water ingestion or improper maintenance.

All comes down to maintenance. I've seen 2000hrs and the motor be fine! I've seen dead at 100hrs, or less. Stock merc 502's and 454's can last a very long time. Don't overheat, keep fresh oil, don't over rev, nothing to lean them out or cause timing issues. Along with no water ingestion issues from bad manifolds or risers. However the above factors seem to come into play far to often. Do a compression and a leak down, along with a bore a scope camera. If all's good run them. Stay on top of maintenance and they will serve you for many hrs to come.

Did my heads on both engines 2 seasons ago. cylinder walls looked awesome. Compression check 160+ across the board. For some reason the machine shop left the exhaust valve oil seals out. The intake valves have them I guess it keeps the guides lubricated better. Did this at 500 hours. I use Amsoil 20-50w Zrod oil only. Very High Zinc oil and I change the oil every 25 hours and soon as it starts to turn a darker color. Engines run great 509's 500 HP each. I do get a puff of smoke on start up when hot because of the valve seals not installed but only for 10 seconds.