CD12 strange cooling issue

[Fastwin18]

Remarkably that same hole is also not there in the gasket listed on vintage outboard

[crosbyman]

not sure what you have there…an open passage may cause water pressure loss or a blocked passage way could do the same !

install the correct gasket

 

if the PH is off.. .why not backflush it  or front flush it to see how much water does get restricted ..or not .

 

give it a shot of 100psi blast … or flip the ph upside down and fill the water inlet with  warm  10-20% vinegar overnight.  It may dissolve some crudded passages

Joining AOMCI has priviledges 🙂

[Fastwin18]

Yes I’ve ordered a new gasket, but it will take a few weeks to arrive. In the mean time I would like to eliminate other possibilities.

crosbyman wrote:

give it a shot of 100psi blast

Assuming you mean a blast of air, I’ve done that already. I’ve found nothing that was obviously wrong.

Regarding back/front flush, that would be using water, right? That would give a clear idea if anything is blocked or not since water behaves differently than a blast of air. A blast of air would get past an obstruction easier than water.

What is the difference between a back or a front flush, just the direction of the flow of the water? I’ve never flushed the powerhead before.

[Tubs]

Try the drill on the drive shaft again but this time block the flow with you finger looking for water squirting out anywhere. Then slip your finger off and watch how well the flow recovers.

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

1 user thanked author for this post.

Fastwin18

[crosbyman]

the ph has an incoming  water passage at the upper end of the   water tube.     The water  flow may or may not be distributed by the fancy gasket when installed and doing it’s thing  but see if you can establish the cooling routes  into  sections of the PH    and  pump water in and look at the output water ports. One certainly dumps water in the exhaust cavity.

Once you have established the flow routes  and pumped in water  you will see if the ” inflow” looks restricted from exiting the PH… indicating  internal blockage blockage.

 

 

 

water should flow out where it normally dumps the

Joining AOMCI has priviledges 🙂

[Fastwin18]

Tubs wrote:

Try the drill on the drive shaft again but this time block the flow with you finger looking for water squirting out anywhere. Then slip your finger off and watch how well the flow recovers.

Thanks Tubs.
When I put my finger on the hole, pressure builds up immediately and the water forces itself past my finger. It hit the ceiling in my workshop. So I’d say that has both plenty of volume and pressure. It seems to confirm the problem is higher up.

[Fastwin18]

crosbyman wrote:

Once you have established the flow routes  and pumped in water  you will see if the ” inflow” looks restricted from exiting the PH… indicating  internal blockage blockage.

I will give this a try, hopefully today.

[Tubs]

My guess would be you have the remains of a failed impeller that are moving around to block the flow of water as it begins to pass through the power head.

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

[RICHARD A. WHITE]

Could the grommet at the top be collapsed and be restricting the flow? Or tube not entering properly, that will also give some water but not proper amount…

Richard

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[crosbyman]

top grommet looks fine (see water sprouting & drill test )  likely an obstruction has suggested.   I would try to fish a  very small diameter  SS  strand wire  inside all access points ( IN water port,  Water exit port,  Jacket  incoming source and exit holes  etc..etc..

seizing wires | McMaster-Carr

 

Joining AOMCI has priviledges 🙂

[Author]

Posts