2.5 260 compression question

[barnhauler]

hello, i have a problem with my 2.5 260, i checked the compression the other day and they all read about 115 on all 6 cyl,, i pulled the heads off and seen that my head gaskets were deterorated, and that water was gettin in the engine,, i replaced them with a 1 mm and checked the compression, they all read 130-135, i took the boat out and it ran like a dream, on way back i got on it bout 7,000, then suddenly noticed that it didnt run as crisp, got home and copmpression is back down to 115, not sure what to do , did a leakdown and everything is good, where is my compression going out?

[Jay Smith]

FIRST WELCOME TO SCREAM and FLY !!!!

Sounds like the sealing surfaces ( block OR head ) isn't flat. If you remove the head and see that the gaskets have failed again I would use a square and check for an uneven sealing surface on both the head and block.. The only places you could be loosing compression is the rings/bore, the head gasket, or the spark plug seal... After the piston rises above the exhaust port there is now no other place that compression can be lost. The water getting in is another matter. Make sure your not having water entering the bores through your fuel system. I'd let the boat set over night and if you have a rear pick up tube elevate the trailer jack so if there water in the tank it would migrate to the bottom and near the pick -up tube. remove the supply line from the motor and pump some in a clear glass jar and see if there is water in your fuel tank...


"Be who you are and say what you feel....
Because those that matter...
don't mind...
And those that mind... don't , Won't or will EVER
matter."

Jay

[barnhauler]

thanks bud, i will pull them off tomorrow and check the block-heads, its gotta be a sealin problem somewhere like u said, i dont have but bout 50 hrs or so since rebuild in 2006, dont really think its the rings