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  1. #6

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    Is this a PCM GT-40 engine? edit: I see from the valve cover that it looks like a Pro Boss / HO ... some variation of 351. Neither here nor there, just confirming that it's a "Ford."

    I had a similar problem a few years ago but it was only after idling for long periods of time. You can read all about the saga here: https://forum.supraboats.com/showthr...-hose-overheat

    But one thought I had was that after getting hot once or twice, the 3 1/2" hose itself was collapsing internally and sealing off the water port on the manifold, not allowing water to pass through efficiently. However, this turned out not to be right. Or at least, not the whole problem.

    What I would do in your case is remove the whole manifold and riser from the engine, then thoroughly flush out both and reassemble. Minimal cost - the gaskets are cheap. This will eliminate the possibility of rust buildup causing a blockage in that assembly. In that process you'll have to remove the hose from the thermostat to the riser, which is good to check out too. Maybe there are some old pieces of an old impeller in there?

    Be mindful of the location of the closed port on the manifold-to-riser gasket, it goes toward the stern which forces water to go up and over the riser rather than up and straight down through that 'easiest path' on the rear, lowest part of the riser. Where was that closure when you took it apart just now? It looks like it was correct in the pics. But once you clean off all the old gasket material, it can be hard to remember.
    Last edited by SquamInboards; 05-11-2016 at 01:37 PM.

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