02' vx225tlra overheating???

[legion33]

ill start off by saying ive went through all of everyones issues concerning this problem on numerous sites. I am clueless. ive changed the pressure relief valve w/ updated kit, spring grommet, ive changed impellar, replaced exhaust gasket which was melted thought that would fix it but no, replaced thermostats, checked the exhaust tuner for clogging.
it is definitely overheating because last year I blew the spark plug out of middle right cylinder and the top was about to blow. I replaced the two top pistons and head, before doing stuff mentioned above at start of this season. got it all together and on the muffs the left thermostat stays at around 135* but the right side will keep going way past and without a buzzer, but in the lake I get a buzzer by the time I idle back to dock to pick up my partner.
I got frustrated and took it to marina they couldn't figure it out either and im gona get a bill for them changing the impellar because they said mine was broke. the only thing left they said to do was pull heads and backflush the system to check for any passages clogged. im not letting them do that so is it necessary to remove heads to do this backflush or what do I look at or look for?
sorry but I need to fish and this is frustrating

[Sequoiha]

have you checked the water pump housing for melting, and also the tube and passage from the water pump to the power head. maybe a restriction.. I have seen the rubber grommet put in backwards in the water pump housing, and the lower unit not going up easy so they pull it up with the bolts, thus bending or creasing the water tube. just a thought

[BIGELOW-]

Not familiar with your particular motor, but what I would do is drop lower unit, put hose/spray nozzle in pisser (backflush) then put hose/spray nozzle on water Pickup tube in midsection) and spray up.

I had a similar problem on a Honda fourstroke, where the pisser hose came out of the block , there was a brass fitting, I screwed it out and flushed it from the bottom- low and behold pieces of an old disengrated impellar were stuck in the head and couldn't get out till I unscrewed that fitting, making the hole big enough...