cooling flow

[bbdave]

Finaly got to run my 40 plus in the water today to start with i get water flow then after a few minutes it stops i cut it and do some rowing then if i start the engine again the same story water flow for a few minutes then it stops. Any ideas?

Dave

[Horsley-Anarak]

I would say that the cylinder waterways are rusted up, has this engine been used in the sea alot?

After the engine has run for a bit and the cylinder gets hot, it does not take much steam to stop the flow of water.

I had a 40+ that this happen to.

Whip the head off and have a look (be aware of the risks involved, shearing off bolts) I expect that you may find the waterways are clogged up.

H-A

[Francis]

I will second the opinion that the waterways are all plugged up. The exact same thing happened to my silver century. After a great deal of mining for impacted rust and crud, she cools well and no longer steams up, inhibiting the water flow.
That rowing between cool downs gets old fast, or should I say Sloooow…

[bbdave]

Oh bum big job then (for me any way) i'll start spraying WD40 on the bolts for a week or so. The boat is primerily a rowing boat the engine is just auxilery power.
It's a motor i bought and spruced up so no idea of it's previous life.

Dave

[bbdave]

I have just had a little go at the bolts and they turned easily so i have sprayed some more WD40 on them before going any further. Do i just remove the bolts and the head just comes off?

Dave

[Horsley-Anarak]

Yes that is all you need to do, just take care not to damage the head gasket.

I anneal the gasket if in good condition and reuse.

H-A

[bbdave]

Well i went for it this afternoon the bolts came out easy would the clogging in the first picture have caused my problem? i cleared it with a small tool then flushed it with fresh water and a large capacity syringe hopefully the second pic shows how it should look. I have used the original gasket as it looked fine.

Before will this have caused my problem


after


Dave

[Horsley-Anarak]

Perfect.

Let us know if it has worked.

I think having a look in the waterways will ensure that there is no problem there for a good few years.

H-A

P.S. the only other thing that might be worth doing is to drop the leg and exhaust off an make sure that the water feed pipe and union that is screwed into the block are clear. But this is just belt and braces.
Looking at the general condition of the engine it should all come apart quite easily, so if nothing else you will have familiarised yourself with some of the other parts.

[bbdave]

Took it out for a run today and all fine loads of water coming through now it started second pull as per ran a tad lumpy for 5 mins then the revs picked up and it ran perfectly. thanks for the help

Dave

[outboard]

Sounds like a good job well done. I folowed your eample and stipped down one of my blocks, and found the same situation, lots of gunk. Can anyone tell me if the copper gasket is made up of three laminates of thin copper or has my head been fitted with three gaskets?
As I had the whole engine stripped I looked at the feed pipe and to be sure it had plenty of gunk in it too. Just reading this thread pushed me into doing this, and I've probably given the engine a few more years by doing so.

Thanks guys

[Charles uk]

Your water jacket before cleaning, is not what you'd call a bad one, unless the tell tale area or the inlet water tube fitting had a blockage, you wouldn't expect any major problems except a slightly reduced flow.

A bad one is when 80 to 95% of the water jacket is packed solid with a rust coloured concretion & compressed air will only just pass through. Yours looks like 10 minutes with a 6mm bar & it's almost ready for reassembly, I think Ha means by bad is one, is one that you have to start cleaning with a masonary drill bit in the cordless drill, just to find where the voids are supposed to be, then another 2 hours sculpturing work with a long electrical screwdriver & a toffee hammer.

When I can find the charger for my camera I will post pics of a a few really bad examples, one that has cracked through to the bore. I kept this one as as a good source of concretion for testing all the descaler chemicals that have been suggested.
The only one that had any worthwhile effect was "Novamax" from Henkel Metal Chemicals, which after pumping a warmed 5% solution through a medium to bad water jacket for 6 weeks removed all the concretion turned the solution from a weak urine colour to dark grey / black, & left a surface finish like sandblasted timber with a very pronounced grain effect with a black coloured finish.
Novamax is used for descaling salt water injection pipes used for pumping water into depleated North Sea oil fields.

I can't find any mention on Google perhaps I've got the name wrong.

[Horsley-Anarak]

Great, glad it is running well.

What no pictures?

H-A

[Charles uk]

Here's an example of a couple of cylinders that might need a little more than a soapy flushing!

On the left an SD110 inboard & on the right an AD 102.

[Hugz]

Reminds me of the time I put a wrench on the spark plug of a 102 and the top of the barrel flaked off with the plug attached.

[bbdave]

I have a picture in the boats for seagulls section

dave