After the boat went into the water and all overboard valves were checked as well as hose connections, the mud boxes were filled up and before the engines were started ,to prevent that the sea water pump would run to long dry, although prepared with acid free Vaseline, I filled up the pump with water through one of the plugs above the pump.
With one engine there was not issue but the other engine the water ran straight out of the pump through the mechanical seal.
Although I'm familiar with these type of pumps they are not all the same and especially the older pumps from around 1970 are not the same as build as these days.
To know which pump type was installed on the engine, engine manual does not informs you which pump actually is installed, I had to remove some paint from the cover and was able to check for the correct type. The one installed on my engines is a 1" type of pump.
I was a kind of lucky to find this information since from the other pump the original cover was removed and replaced by a stainless steel cover.
Going through the internet to find the correct drawing, which took me some time I found a Johnson manual with drawings and spare part numbers.
Going through this manual I also noticed that quite some parts are not available anymore which created some concerns from mys side, since I expected that the mechanical seal was broken.
The found drawing in the manual gave me an better idea how the pump was build together.
See below drawing.
As can be seen from the next picture of the other engines sea water pump the cir-clip is clearly visible.
To be able to run the engine and not filling up the bilges a rubber O-ring was placed between the housing and the stationary part of the mechanical seal and by installing the impeller the mechanical seal was compressed and in such way there was no leakage, although I know this is not the correct way of repairs it fits it purpose and in the man time I was able to search the internet for the correct parts.,
The idea was to completely overhaul the pump and replace all wear and tear parts, items 2, 4, 6, 8 on the drawing. Reason was that I have no idea how many running hours the pumps do have and if they are still able to give enough cooling water to the engines on long runs.
There the challenge started as I could not find any company in Holland who as able to supply all parts I required.and I ended up in the USA with a company who was able to supply all required parts.
After the new parts were received the first step was to remove the pump again from the engine and check the condition of the pump shaft to see if there was an issue to install the circlip. As can be seen from the below picture the groove for the circlip to keep the mechanical seal in place was completely filled with rust, most likely an incorrect type of material was used for the circlip when the last overhaul was performed.
After cleaning the rust and debris out of the shaft the groove became visible again.
The next step was to check if the circlip would fit in the groove and would remain in position after being installed, this was the case and the circlip was removed again.
The following step was to take the pump further apart and to check the dimensions of the old parts and the new parts, the wear might be less than I would expect and there might be no need to exchange the parts and safe the new parts for the future.
The cover as can be seen from the picture showed quite some wear actually the thickness of the old cover was 2.2 mm while the new cover is 2.5 mm.
The covers was replaced on both pumps.
The next part which was removed was part No. 2 the guidance piece for the impeller, it's simple to remove just unscrewing from outside.
On both pumps this part was not stuck. Checking the measurements at the thickest part I noticed quite some wear, old one 4.5 mm new one 6.3 mm and this was a good reason to replace this part on both pumps. On the picture this wear is also quite visible.
I do not think that this wear will reduce the capacity of the pump since the impeller will still be able to close the suction from discharge side.
The next part which was changed was item 8 the bottom wear plate where the impeller runs over.
The plate removed was 1.7 mm and the new plate 1.8 mm not much wear but one could see the area where the impeller had ran over.
The mechanical seals were inspected and I could not see any damage to the running surface nor excessive wear and therefore they were reinstalled and not replaced.
What I noticed that when i put all new parts in the pump housing that item 2 was slightly sticking out above the surface of the pump housing. This was solved by cleaning the bottom surface of the pump housing since over the years time some debris and corrosion had been building up preventing that the bottom wear plate item 8 could be completely going in its place.
Below picture shows all new parts installed including the ring between circlip and mechanical seal which was not found when taking the pump apart, might be that at earlier overhauls this ring was not installed but according to the drawing it is a part of the pump and therefore I did install the ring.
Pump installed on the engine and the circlip installed on the shaft, this went relatively easy and therefore I think that the ring between circlip and mechanical seal is a part of the original installation of this pump. The circlip is not from steel or stainless steel but from brass , therefore it does not stick out on the below picture, but can be seen.
The pump was further build together impeller installed and new cover with new screws completed the overhaul . A test run was done with the engine and although difficult to see it looks like that some more cooling water is running through the engine and I also have the impression that the pressure is a bit higher.