1960 JW-16, pumping water but not cooling

[siriussr]

So kind of like the title says, when the outboard is running in a bucket of water, I am getting good water flow out of what I assume is the water exit (6 holes covered by a small plate on the shaft). At the same time, the cylinders are heating up and the water being expelled is still cool. Any ideas what is going on? I have searched the internet to try and find an answer and cant figure it out. Thanks in advance!

 

[nwcove]

Re: 1960 JW-16, pumping water but not cooling

welcome to iboats siri. when you say the cyls are heating up, do you mean they are roasting hot, or just quite warm to the touch, or if you spritz water on the head it sizzles??

 

[F_R]

Re: 1960 JW-16, pumping water but not cooling

Very common problem with those is the water tube gets bent (bowed) when shoving the lower unit on withouot lubricating the rubber grommet in the water pump. Then it rubs on the spinning drive shaft, wearing a hole in the soft copper tube. Water spills out the hole and blows out the indicator holes, without ever going all the way up to the powerhead.

ALSO: A couple of parts on that motor are not water cooled and get hot as blazes. They are the flat exhaust cover plate on the side and the area right around the spark plugs. This is normal.

 

[Humperdink]

Re: 1960 JW-16, pumping water but not cooling

If you find your water tube is not clogged, and you are getting water to the thermostat,it sounds similar to a problem I recently had with a 6 hp and posted about yesterday.

I ended up pulling the head and cleaning all the cooling passages and cavities. Dont forget the ones under the head gasket. The water can be flowing and just bypassing all the passages and coming out. make sure the water can take every possible path.

I forgot to mention in that post that i will be soaking it to clean it further and replacing the head gasket soon.

 

[siriussr]

Re: 1960 JW-16, pumping water but not cooling

Thanks everyone! I popped the head off and it was full of crud. I scraped it all out and turned the motor over with a drill to check flow and it is now flowing freely. installed everything and she runs much cooler now.