Greetings. I just bought a 1989 Searay powered by a 454 and after my
second outing I noticed it was running poorly. After some advice from
my friendly neighbor we discovered water in the no. 1 cylinder. He
promply told me that it was most likely a blown head gasket and
prepare for the worst. However, when removing the plug from the no. 1
cylinder I noticed a loose washer on one of riser mounting bolts.
They are SS and were installed for the previous owner shortly before
he sold the boat. Now I'm wondering, could the water be entering the
cylinder from an improperly seated/sealed riser? I haven't done
compression checks yet, but oil does appear to have a small amoung of
water in it. The engine has 523 hours on it and ran fine when we took
it out before I bought it. Thanks in advance for any great ideas or
advice.

Mercruiser exhaust are famous for leaking water between the riser and
manifold gasket. Pull them apart, check for flat and cracks, and get the
new gaskets from Merc. Use high temp RTV on them, and put it back
together.


"Frank" wrote in message
om...
Greetings. I just bought a 1989 Searay powered by a 454 and after my
second outing I noticed it was running poorly. After some advice from
my friendly neighbor we discovered water in the no. 1 cylinder. He
promply told me that it was most likely a blown head gasket and
prepare for the worst. However, when removing the plug from the no. 1
cylinder I noticed a loose washer on one of riser mounting bolts.
They are SS and were installed for the previous owner shortly before
he sold the boat. Now I'm wondering, could the water be entering the
cylinder from an improperly seated/sealed riser? I haven't done
compression checks yet, but oil does appear to have a small amoung of
water in it. The engine has 523 hours on it and ran fine when we took
it out before I bought it. Thanks in advance for any great ideas or
advice.

I agree with the other poster. Remove the riser, clean it up, chase the
threads in the manifold with a tap, reinstall with a new gasket. If this
fixes it don't forget to change the oil. Water gets past the rings into the
oil so that can still be explained by the riser leaking.

"Frank" wrote in message
om...
Greetings. I just bought a 1989 Searay powered by a 454 and after my
second outing I noticed it was running poorly. After some advice from
my friendly neighbor we discovered water in the no. 1 cylinder. He
promply told me that it was most likely a blown head gasket and
prepare for the worst. However, when removing the plug from the no. 1
cylinder I noticed a loose washer on one of riser mounting bolts.
They are SS and were installed for the previous owner shortly before
he sold the boat. Now I'm wondering, could the water be entering the
cylinder from an improperly seated/sealed riser? I haven't done
compression checks yet, but oil does appear to have a small amoung of
water in it. The engine has 523 hours on it and ran fine when we took
it out before I bought it. Thanks in advance for any great ideas or
advice.