200hp efi overheating

[workboot]

2002 0t556519, in 2023 I replaced head gaskets on starboard side because of water in the 2 lower cylinders, ever since then the temp. gauge goes up above 2000 rpm. it's only on the starboard side that gets hot, I've changed water pump, poppit, rydelimed it but it still gets hot, looking at my factory manual it says there are rubber water dams between the pistons on the block. Quote "rubber water dams -if missing may result in uneven cooling of cylinders and scuffed pistons" but looking at online retailer's diagrams I cannot find them. I'm not sure that they were there when I did head gaskets. I found out about them looking through my service manual at a picture called water flow diagram. Does anybody know about these or any other reason it might be overheating. Also it does it with or without thermostats

 

[Dukedog]

those are usually called "diverters".. we would put 'em our hot rods years ago before merc ever thought 'bout 'em.. never seen 'em on any Parts charts except later model Hi Perf. 2 stroke stuff ie: 260, 280 etc... they should not be a problem.. earlier production mercs have ran for years without 'em.. when you replaced tha head gaskets did you have tha head checked for being totally flat?

i did find a dia. that shows their location but file is to big to put in a post.. can email it ya want?.. all they are is a piece of 5/16 fuel hose cut ta length.....

 

[Dukedog]

if you cut and install yourself tha length will be estimate.. it needs about 1/4" gap at both ends when installed.... these don't need ta be exact measurements......

are you getting any type of overheat alarm??? if not, i wouldn't think twice about it....