Question re Johnson seawater pump

I have a Johnson F4B-9 cooling pump which is leaking water from the rear where the cam comes out. I do have a spares kit which includes five gaskets, (one of which I just found in my tea), a rubber O ring which looks as though it is the face plate seal, an impeller and what looks like a grub screw but it is quite long.

I'm a little bit trepidant about taking the bugger to pieces as I have just put my motor back in and don't want any hiccups to slow down the process.

Can anyone tell me if the leak is likely to be coming from the bearing?

Hi Japie

Not familiar at all with the internals of your pump but in mine on my 2gm Yanmar there is 2 bearings and a seal with the seal being closest to the impeller to prevent sea water coming out of the front of the pump behind the pulley

In the photo the bearings are numbers 16 and 17 and the seal is 18

If you have a water leak past the seal you would normally replace the bearings and the seal and have a good look at the surface on the shaft where the seal lip runs to make sure there is no grove worn in it

Regards Don

Its hard to see properly but Id say the seal number 18 would be worn and letting water leak.
Some pump housings have a hole behind the pump housing in your pump Id say just behind the bolt flanges on the other side from the pulley
if that make any sense
it would look like a normal oil seal probably
it stops water coming out from where the impeller runs

If you think of the old Holden water pump and just behind the pulley there's a hole in the pump housing so water can escape if the seal is leaking
www.oldmarineengine.com/discus/messages/3/139411.html
see the hole in this photo on the impelor side of the hole there will be a seal mostly likely a normal double lipped oil seal.
The Johnston run a stainless steel spring in the oil seal where as a genuine bukh oil seal runs a bronze spring ( bit a of useless info there
Japie)
That's why there a real sea motor you wont find that in a marinize small truck engine that Cisco runs

Japie,

sounds like the seals are leaking and if you have to go that far you may as well overhaul the entire pump.

3 x bearings, and double lipseal, .... easy enough if you take your time and lay out parts as they come apart ....in order.

Here is the link to the parts list for your pump and the exploded drawing for it.

www.pumpvendor.com/media/johnson/Johnson_10-35240_series.pdf

I have never dealt with these guys but ..... say they send their parts worldwide.

Hoping it helps

Thanks DKD, Ramona, HG and Don

I did a whole heap of reading and video perusing last night and have reached the same conclusion, rebuild is in order. What a mission this has been. I have had the motor out, repaired the alternator mounting and cleaned her up and painted her but in the process I bust the temperature sender which shouldn't be too hard to source here and the fuel cut off solenoid is playing up. I'm going to attack that after I have my boiled eggs!

Thanks Sam.

I finally managed to get the engine started. Had a conniption when I found salt water in the inlet manifold until I realised it came from the bottom of the dinghy when transporting the engine from shore.

She's purring as I type. I've take the solenoid off and will not replace it. The throttle turns her off when pulled tight back.

And the raw water pump has stopped leaking! I will still get a rebuild kit though.

I have a VDO sender if its any use to you Japie part number 320.002 still in the packet can pack it with your burner that's three beers now
Still not sure who's going to drinkem

Select to expand quote

HG02 said..
I have a VDO sender if its any use to you Japie part number 320.002 still in the packet can pack it with your burner that's three beers now
Still not sure who's going to drinkem

Thanks HG but I managed to find one.

Fiji is an astonishing place for sourcing stuff. I imaging most small island nations are the same. Because of the island thing and duty, which is horrendous and follows no logic, suppliers have developed in a really unique fashion.

Here's a classic example. Last year I was looking for some sanding discs for my Makita orbital sander. Quite a few stores stock Makita, and a couple actually have quite a good range. Think any of them carry sanding discs?

It took a lot of questions to finally find them in a little shop out of the way which stocked no Makita's or any other power tools.

When the velcro pad gave out I gave up before even trying but just happened to pop the question one day in a big hardware store. Oh yes we have one of those! And it was quite cheap!

Word of warning to anyone coming here who uses a kerosene stove, bring heaps of metho, it's more expensive than vodka, literally.

Except for the plastic hose. Reinforced rubber would be nice with double clips for the hoses below waterline.