1gm10 with coolant issue

[lexi]

My recently rebuilt engine has been running great for three seasons. This year I had drained coolant completely. Started it up nicely, but no water from exhaust. Closed it down and there was nothing in the Vetus plastic filter unit. I filled the reservoir with stop cock off. Started it up and water came out. Went out and within 15 mins, the alarm sounded and I found filter unit dry. Filled it again and made it back to port as alarm sounded again with filter unit dry. Stripped off impeller, looked good. Put a spare in that was good when I put a new one in, and same story.
I took Vetus unit and the hoses home and checked them with Vacuum Pump and an airline. They were good. Put it back together and took boat out again........same story. fitted new paper gasket to raw water pump flange and tightened speedi Screws in case there was air ingress, no luck. This set up has worked for 5 years with no changes. The seals on pump were renewed 2 years ago and all engine hoses are new. I will check the raw water pump by stripping it out and taking to the bench. My Vetus filter tank has always been 6in above waterline with no issues. I looked at new raw water pump cam in case it has wear. Price is a joke . Any ideas guys?

 

[garymalmgren]

I filled the reservoir with stop cock off. Started it up and water came out. Went out and within 15 mins, the alarm sounded and I found filter unit dry.

All of the water in the filter has been pulled out by the pump. So the pump seems to be working.
This would indicate that cooling water is not entering the filter from the cock.

Is your cooling water inlet cock opening properly? Is the water inlet through-hull fitting chocked?
Disconnect the hose at the cock and open to test.
Is your Vetus filter below or partially below the water line.
Usually the filter should fill when the cock is opened. (with the lid off ).

gary

 

[lexi]

T

I filled the reservoir with stop cock off. Started it up and water came out. Went out and within 15 mins, the alarm sounded and I found filter unit dry.

All of the water in the filter has been pulled out by the pump. So the pump seems to be working.
This would indicate that cooling water is not entering the filter from the cock.

Is your cooling water inlet cock opening properly? Is the water inlet through-hull fitting chocked?
Disconnect the hose at the cock and open to test.
Is your Vetus filter below or partially below the water line.
Usually the filter should fill when the cock is opened. (with the lid off ).

gary

Thanks Gary. Vetus filter is 6inch above waterline........always has been. I ran a wire down the stop cock. It goes through when open and when closed it stops against ball valve. I could try to lower the filter to see if it made any difference? As I say, it has ran at that height for years. If I leave seacock open and try to fill reservoir, it seems to stay empty? Don't know if that is here or there.?

 

[vas]

if the filter is 6in above w/l its unlikely to fill with the lid off. However if the pipe is clear you should see the water level where it should be.
This looks like an air leak issue.
Could be anything from misplaced o-ring on the vetus filter lid, to air leak on the pipework from filter to pump...
As Gary says, if with closed stop cock (the only way to fill it btw!) the pump manages to suck the air, it means i's fine.

 

[garymalmgren]

Hi Lexi
If you remove the hose from the cock and open it does water flow?

RE If I leave seacock open and try to fill reservoir, it seems to stay empty?

This would indicate a blockage (Kelp, plastic, shell) between the inlet cock and the filter inlet ,

RE Vetus filter is 6inch above waterline........always has been.
That seems to be correct by the Vetus guide
Gary


Gary

 

[DOILY]

A worn end plate on my Jabsco raw water pump (similar design?) was the cause when I had same issues. A new plate fixed it. I was surprised what difference a small amount of wear, caused by the rotating impellor, made.
Just a thought.

 

[garymalmgren]

RE VAS Could be anything from misplaced o-ring on the vetus filter lid, to air leak on the pipework from filter to pump...

This was my first though, but Lexi says that the pump pulled all of the water from the filter twice and then would not pull wateer up from the inlet through the filter.
Something strange in the filter area. ??

 

[lexi]

Thanks for all the tips. Before I take the raw water pump off to have a real look at plates and cam on the bench, I will try lowering the filter unit. My thinking is that why ask the pump to pull up to that height when gravity could fill the thing if at the water line? I have proven that with water in it, the pump seems to do a job ( could be weak of course) I realise that Vetus have safety in mind with the 6" above waterline. I close sea cock anyway when left on my very sheltered mooring. The boat is in freshwater and was put in just a month ago whisper clean and anti fouled underneath. Will see how it goes.

 

[lexi]

An update on this. Took the Vetus filter out. Plumbed straight from sea cock to raw water pump. Not a problem. Ran for 6 hrs.
Fixed for me as I have no need for a filter unit in the fresh water of Loch Lomond.

 

[Refueler]

An update on this. Took the Vetus filter out. Plumbed straight from sea cock to raw water pump. Not a problem. Ran for 6 hrs.
Fixed for me as I have no need for a filter unit in the fresh water of Loch Lomond.

Sounds like an air leak on the Filter unit ....

I had a fright when lifted my 38 in .... started 2GM in the slings and water showed at exhaust ... few secs and then no water ... stopped engine ...

Checked the filter unit - dry ! Loosened the top and water came in .. got pal to start engine ... water then was seen to be drawn into engine pipe .. closed top .. all fine. PHEW !!