Doesn't sound like a bad ignition switch. If that was the case you'd lose your gauges at the same time the boat dies. Do you? Sounds more carb/fuel related. Can double check with a timing light, see if you're losing spark when it dies. If not, check fuel filter contents, move on to carb.
I want to emphasize that this sounds intimidating, but it's *so easy*. and your answer is obvious. this literally takes minutes to do and there's no guessing about the result.
despite popular opinion the 3.7 I think it's a great engine. power diff between a 3l is huge. 4.3 is a bit of a bump in power but not as much as you'd think. I might change my tune if I can get a few more hp when i rejet my carb. for the work involved I'd consider rebuilding the 3.7. @Scott...
I don't think there's a difference between marine and auto intake gasket. both composite IIRC.
https://www.rockauto.com/en/catalog/chevrolet,1998,c2500+suburban,7.4l+v8,1303467,engine,intake+manifold+gasket,5424
In that case, you're either dealing with the weep hole in the circulating pump, or just a run of the mill leak. Post a pic. Neither this nor the magnets = dead engine. What the cylinders look like who knows. Did you check compression yet?
yeah, there are magnets glued to the inside of the rotor there, likely what you're feeling. as mentioned, closed cooling and can't think of what would be leaking back there. you're sure it's fresh water and not coolant? show a pic...
other thought would be if you have a leak in the HX that would...
No. it could be stopped by a diode if installed backwards (= no lights), but it couldn't magically apply power to the circuit if the switch was open. Lights wouldn't work at all.
Nope. Not unless it was not a simple on/off SPST switch. The LED can have polarity that an incandescent doesn't, but it won't magically cause power to reach the light that otherwise wouldn't because of an open switch. If anything the light wouldn't work at all. Post a wiring diagram of how to...
