Blown Head Gaskets On A 500hp

[2forcefull]

Anyone know what caused this, #7 blew threw to #5 , #5 tryed to blow thru to # 3, it also blew thru # 7 thru the water hole in to the valley turning the oil to cake frosting!!!!
I know what I think happened, but want to hear from the pros/guru's on motor failer causes

[OutCole'd]

I heard that was kinda common of those motors.

[2forcefull]

gasket picture

[2forcefull]

I heard that was kinda common of those motors.
it's a carbed motor, where did you hear it from???

[2forcefull]

what caused it???

[Daytona100]

Usually blown headgaskets are caused by overheating or detonation.:idea:

[Fiat48]

Is it just me or does that head gasket look like it has been hotter than hell?

[Moneypitt]

Is it just me or does that head gasket look like it has been hotter than hell?
Not only the gaskets, I'll bet there are going to be some cracks from that one........Throw the head fasteners away as well..........MP

[GofastRacer]

Looks to me like the head was lifting, junk fastners or not torqued right???, hope it didn't torch anything!..

[wsuwrhr]

Bummer deal.
Yea what they said....
After you get the motor buttoned back up, you should check out your fuel and cooling systems before you go back out on the water. You may have other problems as well.
Brian
Not only the gaskets, I'll bet there are going to be some cracks from that one........Throw the head fasteners away as well..........MP
Looks to me like the head was lifting, junk fastners or not torqued right???, hope it didn't torch anything!..

[wsuwrhr]

Is it just me or does that head gasket look like it has been hotter than hell?
Hot enough that I felt it.
Bubbles on the blue portion of the head gasket. Serious
Ouch

[wsuwrhr]

http://www.***boat.com/forums/attachment.php?attachmentid=25038&d=1172548596

[SmokinLowriderSS]

Is it just me or does that head gasket look like it has been hotter than hell?
Not just you, that thing has been cooked, and is now WELL DONE. :eek: :(
I think the above advice is good, new head fasteners, and start praying nothing cracked, or warped.

[jbone]

My 502 did the exact same on the even bank last year. We attributed it to a combination of things.
1. Lean condition
2. Timing too high (detonatation)
3. Too hot plug
Unfortunately, I had to nurse it back to the ramp, about 3 miles, and I torched the head and block pretty bad.
I be watching to see what you think caused yours.
J

[gn7]

DETONATION, plugs, timing, or lean, but definitly a ton of heat

[2forcefull]

Ok now that we have heard from some that obvious know what they are talk'n about,here's my thoughts;
I think that sometime previous to me driv'n the boat it got hot' real hot,
but not hot enough to perm. disable it, probley lost a impeller and got limped in.
the old owner stated when I bought it that it idled ruff when cold, but cleared up when it warmed,
I say water was getting to #7 and till it warmed up killed that hole, but as rpms got higher it would pump air into the water jacket, this causing an air pocket to form around the therostat and causing a lower than actual temp reading.
when I first got the boat ( i just got it) i took it to mead and put it in the water, it idled ruff as i was told, so I left it run, it cleared up, but the temp after awhile started to climb to over 200. so I shut it off, the impeller was bad
so I took the boat home
I flushed out all the pieces and installed a whole new pump kit,
now I take the boat to havasu, It idles ruffer but clears up as it warms,
I think that with the new pump pressure going across the lake @ 60 mph blew a whole section of the gasket out, now air is getting to the thermostat say'n its at 160-180 but it's actually way hotter , as it gets hotter the all ready weekn'd headgasket blows between the holes and kills number 5, with the water pump'n in to the valley turns the oil to cake frosting.
what do you think???

[Panic Button]

the first time i took it to the lake I backed in let it run at afast idle,
about 12-15 hundred rpms, warmmed up to about 140-160.
I left it runn'n at idle to make sure everything was all right. I walked to the restrooms at the top of the
hill at lake mead marina, when I got back it was at 220
Depending on how long it was pegged over 220, some serious damage is there I'm sure.... Good luck

[2forcefull]

Looks to me like the head was lifting, junk fastners or not torqued right???, hope it didn't torch anything!..
hey, thanks for getting in on this, I used to run a blown alcohol digger
spent more time read'n head gaskets, pistons, and bearings than the news paper.
kinda wierd, when a merc motor goes, they blame the driver (which is true)
but when an inhouse/custom motor goes they blame the boat!!!

[2forcefull]

the first time i took it to the lake I backed in let it run at afast idle,
about 12-15 hundred rpms, warmmed up to about 140-160.
I left it runn'n at idle to make sure everything was all right. I walked to the restrooms at the top of the
hill at lake mead marina, when I got back it was at 220
Depending on how long it was pegged over 220, some serious damage is there I'm sure.... Good luck
Iwould guess about 10seconds, but just to be on the safe side less than a minute, it was at 160. but i walked 20 yards,
I know it takes a long time to pull out that long, fat, big headed one eye monster, but not long enough to burn up a motor, seen women melt down and start seep'n just look'n at it though

[Panic Button]

I had an impeller that shelled out, the motor went from 150 to 240 in about 2 minutes...

[2forcefull]

I had an impeller that shelled out, the motor went from 150 to 240 in about 2 minutes...
what damage did it cause? was it at idle???

[Panic Button]

It was at idle. No damage at first, but later that day dropped a valve seat (Gen5 motor), ruined the piston.

[Moneypitt]

Ok now that we have heard from some that obvious know what they are talk'n about,here's my thoughts;
when I first got the boat ( i just got it) i took it to mead and put it in the water, it idled ruff as i was told, so I left it run, it cleared up, but the temp after awhile started to climb to over 200. so I shut it off, the impeller was bad
so I took the boat home
what do you think???
Just got it? Well,I think you never, never, never, never, NEVER, NEVER buy a running boat without seeing it on the water. If the old owner would've tried to demo that boat, HE would've had these problems, and you could've saved thousands or just walked away from a bad deal........Just my .02........MP

[2forcefull]

Just got it? Well,I think you never, never, never, never, NEVER, NEVER buy a running boat without seeing it on the water. If the old owner would've tried to demo that boat, HE would've had these problems, and you could've saved thousands or just walked away from a bad deal........Just my .02........MP
Yeah I hear ya, but some times you just trust someone, what happened was the guy is in cal a the boat was in havasu,I was told go run it , it was gaurenteed to run perfect, then it changed to, " I gaurentee you that I'm not tak'n that boat back" I was under the impression that I was to go run it and if it didn't run perfect, bring it back!!!

[Beer-30]

I hope you got a good enough deal on it to somewhat cancel out the fixing.
On the good side, you get to put it together how you want it and you know it will be sturdy.
Good opertunity to change heads to alum and shed some weight. Yours are gonna need alot of work, so the price diff will be worth it.

[2forcefull]

I gave full ask'n price cause of the 100 hr 500hp that runs so perfect!!!!!

[Beer-30]

I gave full ask'n price cause of the 100 hr 500hp that runs so perfect!!!!!
Hourmeters can be changed. Only an ECM would tell actual time. Being carbed, you really don't know how many hours are on it.
For instance:
Mine says 285 hours right now. If one checked the ECM, it says 220. The key was left on during parking one time. Battery charger hooked up and all. So, one day, I will replace it and run the new one up to current hours - prior to install. Then, I will change it to oil pressure circuit instead of ignition.

[2forcefull]

got the heads out getting checked out, then a full valve job

[2forcefull]

well the 500 hp lives, went complete threw it. put it back together with
the o-ring copper gaskets. sound good,gonna run it monday (today)
we'll see
the motor was allways cold blooded says the prevous owner,
it isn't now and I haven't done anything to the carb,
I think water has been gett'n to # 7 for a while