Hi i have a chaparral with twin 454 motors the other day i started up prior to going out port motor ran fine stbd motor was running on like 6 cyl i pulled dip stick oil looked fine no water in oil so i rebuilt carb tried it same problem i pulled plugs #8 was wet ithe water so was #2 pulled riser and manifold everything looked good put new gaskets and plugs started back up same thing i removed intake when i pulled carb i noticed water inside manifold proceeded to take manifold off when i removed it water in oil and one pushrod is flopping around like maybe valve got stuck and that allowing pushrod to be loose