Hey guys just wondering what everyone thinks about this: its my 920cc that went booooom yesterday, its fingerported, ill give more info on it but first i'd like to hear why people think why its gone boom
Hey guys just wondering what everyone thinks about this: its my 920cc that went booooom yesterday, its fingerported, ill give more info on it but first i'd like to hear why people think why its gone boom
LEAN!!!!!!!!!!!#1 is this motor a 50or60 hp block ? the idle releaf`s kinda give it away. Do you race this in some kinda class or play motor?
Hey DW thanks for the reply.. its on a sst60 boat we call them F3's over here. i dont know hp? i would imagine 60 standard or 70. it was the first time i took it out too!! everything seemed fine after the first go then this happened!!!
that looks like a really bad high speed lean out!
or a combination of a lean out and a detenation!
BRP = Better Racing Products!
Like some water was in gas or water in exhaust. Dave
Thanks for the reply guys, ill have it pulled down soon, and work out exactly whats happened. im getting a new sleeve for it aswell as piston, im not sure but this cylinder's sleeve is a tad lower then the rest so maybe this has happened before
thanks guys will post more pics once pulled down!
water got in cyl from blown head gasket
piston top away from ex is grey smoother melted,,,had water on it
from lack of water is a cleaner (more rough or jagged )melt
if look at top of cyl where the sealing gasket is
#1 can see side of allunimum corroded away on left side in pic,,,,,,,
#2 can see steel sleeve is dropped below allunimum
#3 and also seperated,,,,,,,,,,,,,steel to allunimum
there is no way the cylinder had good compression to start with
the corroded area,,,,
1 a guess deduction is that motor was never properly flushed through the yrs of use
2 the corrosion erroded away metal sealing area and allowed head gasket to blow
then ran till fried
3 the sleeve sunk during the excess heat
since corrosion already made loose and sepaerated
4 that sleeve looks as it has been replaced in the past,,
can see 2 steel rings on the bad cyl,,,,,
the other 2 look original
machinest may have
machined bottom of cyl too low or cut bottom of sleeve too much when installed,,,,,
causing sleeve not to be cradled on bottom,,in hense allowing to sink
suggest when replace sleeve (which is a must) go to
an oversize outside diameter,,,,to get rid of the remainder of the factory oem sleeve
and make sure sleeve is installed to hit bottom
had to reword reply
also that looks like a handfull of fun to drive
john
At top speed, unit raised to high out of water. No water no good.
Hey John, it had been rebuilt and only ran twice since he built it, when i got it first thing i did was replace headgasket as it had blown, so the headgasket that was on the motor was brand new. the sleeve was already a little lower before i took it out.. however alot of what you have said appears to be correct... could it be the headgasket couldnt/didnt seal correctly due to sleeve and has then allowed water into cylinder after it warmed up? as i took it out for about 15 minutes brought it back refueled then went out again for about 20mins which is when it blew up!
WestBros:
I think i need a low water pick up too.. just so happens Mr Hill wants something i have and he has low water pick up nose cones!!
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