1986 Mariner 3697- first spring launch/splash

[MrMojoRisin]

Thanks Viper, is there any good reference material/video's you could suggest on doing a raw backflush? Should i be doing that with the closed side too? Coming from outboards, these things are a bit foreign to me.

[bud37]

There are a number of marine grade products designed for fresh water flushing and being able to provide water so you can run your engines on the hard without damage. Many variations in quality and price so do your homework. Lots of videos nowadays.

You can even cobble some up if handy. Makes spring start up less stressful when you know the engines are tip top before getting to lift in....tune ups/impeller changes etc.

I installed fittings to achieve this on all my inboard boats.... when you get to lift in just hit the key, no surprises. ......

[Viper]

Source of the post Thanks Viper, is there any good reference material/video's you could suggest on doing a raw backflush? Should i be doing that with the closed side too? Coming from outboards, these things are a bit foreign to me.

I'm sure you can probably find something on YouTube. In any case, the end of the circuit will be at the exhaust manifolds. You can start there and it should flush through the raw water side of the heat exchanger and the U cooler and come out at the raw water pump. You'll have to remove the outlet hose at the pump. This might also flush out impeller pieces that might be trapped from a previous impeller failure if that's happened in the past but never followed through with a back flush. You shouldn't have to do the fresh water side (coolant/closed side), it wouldn't hurt to test the coolant and check it's condition/colour, rating though. They should have checked that at winterizing time but you might want to check it yourself with a refractometer and record your reading, then compare it to the reading you'll take at winterizing this year. If the reading worsens drastically, you may have an exchanger leak. This is also worth doing shortly after commissioning a couple of running hours later in case they didn't winterize her properly. Pressure testing the closed side will also tell you if there's a problem.