I'd thought I'd write up a little public service announcement about draining cooling water during winterization based on my work this weekend on my boat.
I recently purchased a used 2008 Chaparral 236 SSi with a Mercruiser 350 MAG MPI and Bravo III outdrive. It's always been in fresh water and appears to have been well maintained and babied. It's been quite a few years since I've worked on I/O engines, but I decided to do the full winterization myself, since I'm pretty experienced with this type of work.
My engine has the 3 point drain system - you're supposed to be able to pull out 3 blue drain plugs and, in theory, all of the water in the block, manifolds, risers and Cool Fuel III module will be drained. I did this and let it all drain out.
As a last precaution, I pulled the hoses off the underside of the manifolds to make sure the water had indeed drained - it had.
I then pull off the quick disconnect fittings from the underside of the engine block to make sure all of the water was drained. I didn't get any water to come out, so I assumed it was drained fully. I had remembered many people discussing how these ports can get clogged and trap water in the block. They can get clogged with sand and scale, etc.. So I decided to grab a small screwdriver and poke up into them to make sure they weren't clogged. Sure enough, they were clogged. I poked through the sediment and began working it loose and breaking it up. The water started pouring out of the block. Absolutely nothing had drained from the block when I followed the service manual instructions of pulling the 3 blue drain plugs!
So...lesson to anyone reading...if you have "automatic" drain hoses that exit the bottom of your engine block on both side (see drawing below) - then you absolutely need to pull them off during winterization and poke up into them to make sure all of the water has drained from the block!
If I hadn't have done this...the results would have been disastrous!
Cheers!
I recently purchased a used 2008 Chaparral 236 SSi with a Mercruiser 350 MAG MPI and Bravo III outdrive. It's always been in fresh water and appears to have been well maintained and babied. It's been quite a few years since I've worked on I/O engines, but I decided to do the full winterization myself, since I'm pretty experienced with this type of work.
My engine has the 3 point drain system - you're supposed to be able to pull out 3 blue drain plugs and, in theory, all of the water in the block, manifolds, risers and Cool Fuel III module will be drained. I did this and let it all drain out.
As a last precaution, I pulled the hoses off the underside of the manifolds to make sure the water had indeed drained - it had.
I then pull off the quick disconnect fittings from the underside of the engine block to make sure all of the water was drained. I didn't get any water to come out, so I assumed it was drained fully. I had remembered many people discussing how these ports can get clogged and trap water in the block. They can get clogged with sand and scale, etc.. So I decided to grab a small screwdriver and poke up into them to make sure they weren't clogged. Sure enough, they were clogged. I poked through the sediment and began working it loose and breaking it up. The water started pouring out of the block. Absolutely nothing had drained from the block when I followed the service manual instructions of pulling the 3 blue drain plugs!
So...lesson to anyone reading...if you have "automatic" drain hoses that exit the bottom of your engine block on both side (see drawing below) - then you absolutely need to pull them off during winterization and poke up into them to make sure all of the water has drained from the block!
If I hadn't have done this...the results would have been disastrous!
Cheers!
