2004 Merc 5.0L MPI serial # OWO18920 in a Trophy 2359
So, I've been battling leaky oil pans, malfunctioning gauges, and low oil pressure due to overfilling. The engine was on a pallet for the past 4-5 weeks... Still only have about 10 minutes total running time this season. Got all that fixed and now I have an overheat problem.
Took the boat out tonight and it ran up on step for about 30 entire seconds before she decided to idle herself down. Looked at the gauges and the temp was at about 225. Manifold risers were completely cool, so the seawater pump (closed cooling system) was working, but the temp gauge said hot. It started to cool down while idling and I figured maybe the cooling system had "burped" (it was completely drained last weekend) and was back to normal. Slowly throttled up, got on step for about 20 more seconds before the temp shot back up and she idled down again. Manifold risers still cool.
My limited knowledge makes me think thermostat, but I'm sure there are about a hundred of you out there that know better than I do. Anything else a likely culprit? I'm assuming there's a safety function that restricts the engine when it's too hot. Is that correct?
Is this just a standard automotive thermostat I can get from NAPA or is it something I need to get a marine ($$$) part for?
Also had Joe-Expert at the dock tell me I should just take the thermostat out altogether and run it without one. Is this stupid???
Thanks.
So, I've been battling leaky oil pans, malfunctioning gauges, and low oil pressure due to overfilling. The engine was on a pallet for the past 4-5 weeks... Still only have about 10 minutes total running time this season. Got all that fixed and now I have an overheat problem.
Took the boat out tonight and it ran up on step for about 30 entire seconds before she decided to idle herself down. Looked at the gauges and the temp was at about 225. Manifold risers were completely cool, so the seawater pump (closed cooling system) was working, but the temp gauge said hot. It started to cool down while idling and I figured maybe the cooling system had "burped" (it was completely drained last weekend) and was back to normal. Slowly throttled up, got on step for about 20 more seconds before the temp shot back up and she idled down again. Manifold risers still cool.
My limited knowledge makes me think thermostat, but I'm sure there are about a hundred of you out there that know better than I do. Anything else a likely culprit? I'm assuming there's a safety function that restricts the engine when it's too hot. Is that correct?
Is this just a standard automotive thermostat I can get from NAPA or is it something I need to get a marine ($$$) part for?
Also had Joe-Expert at the dock tell me I should just take the thermostat out altogether and run it without one. Is this stupid???
Thanks.
