2013 Yamaha 242 limited S overheat one engine, pics included, please help with next steps

[DenisRecchia]

Hello all,

Had an overheat issue on my 242 limited S last season near the end of it up here in New England, decided that was a problem for Spring me. Well here it is Spring. My Starboard engine has developed an overheat and I fear I have a blocked up engine block from reading these forums and trying to troubleshoot the best I can. I was hoping for a clogged line or blocked strainer but I am having the same results on the hose or on the water. Posted are pics of cylinder temps before I shut the boat down on the hose in my yard.

I have already replaced both thermostats, blown out the pisser lines, and cleaned the strainers on the jet drives. What is my next step here? Is it pulling off the exhaust manifold or just cutting to the chase and breaking the block down? I am relatively handy and fear this might be above my pay grade, but if I bring it to a local dealer I know I will lose my entire season waiting.

 

[FSH 210 Sport]

Have you verified there is no blockage in the main cooling from the engine back to the pump?

 

[DenisRecchia]

Ok I believe I have, I took apart the screen at the jet pump and there is pressure in the hoses that lead to the block / exhaust. When on the water some exhaust water gets out the pisser but not at the same intensity, and when on the hose water is escaping from the jet pump and the boat exhaust.

Attaching a diagram of the cooling system, where can I disconnect to see what the flow is like? Im a little hesitant to start it up and start popping hoses off to see if cooling water shoots out. For example, could I take it apart at #12 or #15 at the diagram? Or #30?

Is anyone able to show me how the water flows through this?

Thanks as always in advance, trying to avoid a lost season and thousands probably

 

[anmut]

Not sure on this method, but you could try some SaltAway to see if you can unclog it.

 

[Acard7]

T piece #12 is what I would pull off and check. That’s where it would get blocked if anything did happen to get into your cooling system.