how to check the water circuit at sea-water cooling system

[sarantis]

GM 305 (mcm228) pre-alpha outdrive (228)
My boat is now at the garden in muffs and i do my best to avoid having again temperature problems.I've checked and replace many things and i wonder how to check the water circuit.If there is somewhere a leak for example at the water pump or somewhere else ,you say at other threads that air bubles appear at the circuit.If at the final outlet from the thermostat housing towards the elbow i connect a tranparent hose won't i notice the air bubles through it?

 

[sarantis]

Re: how to check the water circuit at sea-water cooling system

(1978 year ).Any opinions please?

 

[erikgreen]

Re: how to check the water circuit at sea-water cooling system

You could just pressurize the whole water system, as is done when looking for cracks in the block. I think you just need to block of the water output at the risers and make some sort of adapter to supply pressure at the water pump.

Erik

 

[Bondo]

Re: how to check the water circuit at sea-water cooling system

Ayuh,......

I just changed out My exhaust manifolds,+ risers,...
The original 4 hoses from the T-Stat housing to the 2 lower ports on the manifolds,+ the 2 higher hoses to the risers were Too Short.... Actually it was Just the Top 2 But,....

Sooo,... I have installed some of that Reinforced Clear Vinyl Tubing in these 4 places,....
I did this for experimental,+ diagnostic reasons,.... I haven't fired it Up yet, 'cause it still needs more Work,... But I'm getting Closer....

I don't know if this Reinforced Vinyl Tubing is going to stand the Heat or Not,... I'm thinking it Will,...
We'll See...
Sooo,..... Even though I still haven't answered your Questions,......
I just wanta let ya know,......... You're Not Alone........................

 

[Don S]

Re: how to check the water circuit at sea-water cooling system

Using clear hose to find bubble will NOT work on muffs. You need to put it in the water for that to work. On muffs you WILL have lots of bubbles, but in the water it may be fine.
You won't be able to pressure check the manifolds and risers while they are on the boat, but you can block off the hoses going to the manifolds and risers, then blocking off the hose going to the transom shield. Then you can pressurize the cooling system and see if it holds pressure. But that still won't tell you if it will work properly.
Personally, if you have it all together and it works on muffs, put in the water and give it a test run.

 

[Bondo]

Re: how to check the water circuit at sea-water cooling system

Ayuh,......

Don,... Have alook at Sarantis' other thread,....

He's Missing the Sleeve in the T-stat Housing,........

 

[Don S]

Re: how to check the water circuit at sea-water cooling system

Well, I guess I missed that thread, really know nothing about the old engines, but I guess it's time to start digging thru my info again...............

 

[sarantis]

Re: how to check the water circuit at sea-water cooling system

Thanks so much for replying.I had to give you more details.Last season the engine had high temp problem.I changed manifolds and risers and some days ago i replaced the intake manifold gasket so with the above test i just want to test the outdrive.
Don S droping in and puling the boat out of the sea is a nigthmare for me.

 

[Don S]

Re: how to check the water circuit at sea-water cooling system

Did you see my reply to your other thread on the thermostat housing?

 

[sarantis]

Re: how to check the water circuit at sea-water cooling system

I saw it and excuse me for the delay and if you find the time take a look at it please.