1978 v20 Mercruiser 470 possible replacement needed please advise

[surchin]

Hi all Scott in Santa Barbara here. Well got the boat in shop and after new fuel new carb petronix ignition it appears my 1 and 2 cylinders are not firing. That's as far as we have gone don't know about compression or maybe bad wire or plug , the easy stuff,. But I am thinking it may be terminal I am expecting worse . I love my boat but what would be best way to replace a 470? I don't have time or place to do work I'll be paying for labor. Not sure what I'm going to do- is there a value to an otherwise good condition v20?

[spareparts]

do a compression test and report back, make sure you have the spark plug wires in the correct order. Its unusual for it to drop two cylinders like that unless it has a blown head gasket.

[surchin]

I'll do that Monday may be possible. we pulled the 4 leads off the distributor one at a time cyl 3 and 4 caused significant change in motor ruining bur no change when taking the other 2 off .

[surchin]

ive been fighting water in fuel, we think that may be cause of the cylindar difference. blew out the fuel lines and seems to be running ok ... i panicked, hah. see how it goes this weekend though ive thought everythings fine before...
thanks

[macojoe]

I and Reel had problems wit the vents being in the wrong place on them old V's, mine let some water in from time to time, we moved the vents higher up on the side to stop fuel from spilling out when tanks were full and to stop water from splashing in from the ocean waves.
How do you think you are getting water in?? Do you have a water seperator0?? If not you need one ASAP