Dripping water pump on yanmar 1G 10

[Thedigger]

Hi,

This has no doubt been answered before but I can't find it on this forum as im a newbie. My yanmar has been out of action for over 2 years. I've replaced fuel filter and bled system. Changed impeller and gasket. Running a hose via a bucket of water through pump I notice that the suction is a bit haphazard and the pump drips. Why?

 

[JumbleDuck]

This has no doubt been answered before but I can't find it on this forum as im a newbie. My yanmar has been out of action for over 2 years. I've replaced fuel filter and bled system. Changed impeller and gasket. Running a hose via a bucket of water through pump I notice that the suction is a bit haphazard and the pump drips. Why?

Sounds as if one of the two shaft seals has gone: there is one to keep air out of the engine and one to keep air out of the pump. They're only £15 or so for the pair (1GMWPS 1GM water pump seals) and fairly easy to change, as long as you fit them the right way round. If you're unlucky the shaft will have rusted during layup and that's a cool £112 (128170-42060 water pump shaft 1GM's).

There was a forumite years ago who made stainless replacement shafts, but I can't remember who he was and don't know if they are still available.

While you're cleaning things up, it would be a good idea to check the oil pipe which runs directly under the pump. It's mild steel and tends to rust under even normal service drippage. Don't replace it with like; your local Pirtek or other hydraulic hose supplier will make you a rubber replacement while you wait for not very much. They can supply new banjo bolts too.

 

[VicS]

Sounds as if one of the two shaft seals has gone: there is one to keep air out of the engine and one to keep air out of the pump. They're only £15 or so for the pair (1GMWPS 1GM water pump seals) and fairly easy to change, as long as you fit them the right way round. If you're unlucky the shaft will have rusted during layup and that's a cool £112 (128170-42060 water pump shaft 1GM's).

There was a forumite years ago who made stainless replacement shafts, but I can't remember who he was and don't know if they are still available.

While you're cleaning things up, it would be a good idea to check the oil pipe which runs directly under the pump. It's mild steel and tends to rust under even normal service drippage. Don't replace it with like; your local Pirtek or other hydraulic hose supplier will make you a rubber replacement while you wait for not very much. They can supply new banjo bolts too.

Surely the seals are to stop water leaking from the pump and oil leaking from the engine and should be installed with the spring side facing the pump chamber and the bearings respectively to achieve this.

 

[Thedigger]

okay thanks for replies. I purchased a service kit that came with fuel and oil filter. The new impeller came with a rubber o-ring. This was a different size o-ring to the one at the base of the bearing. It was much bigger and thinner and I don't know where it goes. Is there a ring or a gasket that fit between the pump housing and the engine? I bolted the pump unit into the engine with three 10mm bolts but there was not gasket or sealant used between the two items. Is that correct. I had a gasket fit onto the front of the impeller. The water drips around the bottom right bolt on the pump and engine. With a hose in a bucket the impeller sucks the water into the system but when I put my finger on the hole where the water enters sometimes there is suction and sometimes there isn't and I switch the engine off.

 

[JumbleDuck]

Surely the seals are to stop water leaking from the pump and oil leaking from the engine and should be installed with the spring side facing the pump chamber and the bearings respectively to achieve this.
View attachment 92866

You're quite right. The main thing is to get them the right way round, and a lot of people, anecdotally, don't. I should have said "Make sure ou put new ones on the same way round as the old ones".

 

[JumbleDuck]

okay thanks for replies. I purchased a service kit that came with fuel and oil filter. The new impeller came with a rubber o-ring. This was a different size o-ring to the one at the base of the bearing. It was much bigger and thinner and I don't know where it goes.

I don't have a 1GM10 any more, but I don't remember an O-ring in the standard set-up. I had a Speedseal cover which used a very skinny large diameter O-ring, but I think there is normally a paper gasket between the pump and the cover. Do you have that in place?

 

[duncan99210]

Given the poor suction/output pressure allied to the drips it sounds to me as if it may not be the seals at fault but the cover plate. If it’s worn and not properly sealed by the paper gasket, then the impeller won’t be working properly as it needs to be in contact with the plate. That’d give the poor pump performance and a drip from the cover plate bolts.

 

[VicS]

okay thanks for replies. I purchased a service kit that came with fuel and oil filter. The new impeller came with a rubber o-ring. This was a different size o-ring to the one at the base of the bearing. It was much bigger and thinner and I don't know where it goes. Is there a ring or a gasket that fit between the pump housing and the engine? I bolted the pump unit into the engine with three 10mm bolts but there was not gasket or sealant used between the two items. Is that correct. I had a gasket fit onto the front of the impeller. The water drips around the bottom right bolt on the pump and engine. With a hose in a bucket the impeller sucks the water into the system but when I put my finger on the hole where the water enters sometimes there is suction and sometimes there isn't and I switch the engine off.

If you are going to do work on an engine a Service manual is a very valuable "tool" to have in the box

There are at least two different editions to be found on line. ........ They may answer your questions

YANMAR 1GM10 SERVICE MANUAL Pdf Download | ManualsLib
https://www.jeanneau-owners.com/Manuals/3GM Engine Service Manual.pdf
( The 1GM10 manual in fact covers all the GM models)

If you dont have one you can also find an Owners manual on the Barrus website and other places, including the ManualsLib site.

 

[Gixer]

I think the rubber O ring goes in the back of the pump housing. you'll see it when you take the pump off.

Refurbishing a Yanmar 1GM10 water pump - Practical Boat Owner

 

[Thedigger]

1. 
   

2. Sounds as if one of the two shaft seals has gone: there is one to keep air out of the engine and one to keep air out of the pump. They're only £15 or so for the pair (1GMWPS 1GM water pump seals) and fairly easy to change, as long as you fit them the right way round. If you're unlucky the shaft will have rusted during layup and that's a cool £112 (128170-42060 water pump shaft 1GM's).
   
   There was a forumite years ago who made stainless replacement shafts, but I can't remember who he was and don't know if they are still available.
   
   While you're cleaning things up, it would be a good idea to check the oil pipe which runs directly under the pump. It's mild steel and tends to rust under even normal service drippage. Don't replace it with like; your local Pirtek or other hydraulic hose supplier will make you a rubber replacement while you wait for not very much. They can supply new banjo bolts too.

   Hi I notice an item called packing at the engine side of the pump. This might be where the dripping is sourced. When I got my service kit it came with a large o-ring is this the packing? Not to be confused with the o-ring at the bearings

 

[VicS]

1. 
   
2. 
   Hi I notice an item called packing at the engine side of the pump. This might be where the dripping is sourced. When I got my service kit it came with a large o-ring is this the packing? Not to be confused with the o-ring at the bearings

There are 2 items called "packing". One is the gasket between the pump body and the cover
The other is the gasket between the pump and the pump body and the engine




It is possible that water could leak from the cover gasket but if the other one leaked it would be leaking oil

The most likely place for water to drip is from the "weep hole" between the water and oil seals. It allows water which has leaked past the water seal to escape instead of being forced though the oil seal into the engine.

I dont see an O ring in the diagrams... If you find one replace it with the O ring in the kit
Perhaps it is supplied instead of the "packing" between the pump and the engine?????

 

[lw395]

Given the poor suction/output pressure allied to the drips it sounds to me as if it may not be the seals at fault but the cover plate. If it’s worn and not properly sealed by the paper gasket, then the impeller won’t be working properly as it needs to be in contact with the plate. That’d give the poor pump performance and a drip from the cover plate bolts.

Very true.

The cover plate and seals have to keep water in. They also have to keep air out if you want any suction.
The impeller needs to be pretty much in contact with the cover plate if you want it to suck air, it will work with a small gap pumping water because most of the water will flow to the engine rather than back past the impeller.

Some impeller pumps will actually work OK with the seals completely shot, because the impeller seals the pumping chamber front and back.

It may be possible to get a pump shaft rechromed and reground.
If the shaft is bad where the seal bears, it may work adequately with the seal turned around, or spaced towards the engine by a washer so it bears on a fresh bit of shaft.
You can also polish the damage on the shaft with fine W&D, with a new seal this got me a couple of seasons out of a shaft that had a sharp wear line around it which chewed the first seal in no time.

 

[Thedigger]

There are 2 items called "packing". One is the gasket between the pump body and the cover
The other is the gasket between the pump and the pump body and the engine

View attachment 93247


It is possible that water could leak from the cover gasket but if the other one leaked it would be leaking oil

The most likely place for water to drip is from the "weep hole" between the water and oil seals. It allows water which has leaked past the water seal to escape instead of being forced though the oil seal into the engine.

I dont see an O ring in the diagrams... If you find one replace it with the O ring in the kit
Perhaps it is supplied instead of the "packing" between the pump and the engine?????

I see. Just im reluctant to open up the pump and replace the water seal

 

[VicS]

I see. Just im reluctant to open up the pump and replace the water seal

Recheck what you last did
You said you'd replaced the impeller and the gasket.........Take the cover off again, check the gasket inspect the cover and the face of the pump body ... make sure there's no old gasket stuck on there and refit, A light smear of grease wont hurt.

If it still leaks check underneath the pump body to see if water is dripping from a weep hole. If it is then its the water seal that is leaking. No option but to replace the seal if you are to cure the leak

 

[Refueler]

Given the poor suction/output pressure allied to the drips it sounds to me as if it may not be the seals at fault but the cover plate. If it’s worn and not properly sealed by the paper gasket, then the impeller won’t be working properly as it needs to be in contact with the plate. That’d give the poor pump performance and a drip from the cover plate bolts.

My plate dripped ... I have no idea if my Perkins is similar .... but the impellor is a close fit up to the face plate ... the plate having about 12 small bolts holding it in place .... I gave the plate a smear of red hermetite and it stopped the drip.

I do have another drip at rear of the pump body where shaft exits to meet the shaft inside block. To replace that is a pain on mine - so I accept it .... been like that for about 10 years ..... no worse .....

 

[Thedigger]

Recheck what you last did
You said you'd replaced the impeller and the gasket.........Take the cover off again, check the gasket inspect the cover and the face of the pump body ... make sure there's no old gasket stuck on there and refit, A light smear of grease wont hurt.

If it still leaks check underneath the pump body to see if water is dripping from a weep hole. If it is then its the water seal that is leaking. No option but to replace the seal if you are to cure the leak

I looked into the peep hole as it was dripping and couldn't see water but it's hard to see it could be I didn't tighten the 3 seven mm bolts on the cover enough.

 

[Refueler]

I looked into the peep hole as it was dripping and couldn't see water but it's hard to see it could be I didn't tighten the 3 seven mm bolts on the cover enough.

Make sure you tighten evenly all round in sequence - NOT fully tighten one then another ... do them all incrementally to make sure cover is nicely evenly flat closed.

 

[Thedigger]

Make sure you tighten evenly all round in sequence - NOT fully tighten one then another ... do them all incrementally to make sure cover is nicely evenly flat closed.

Yes I have ordered pliers to for the clips and a water seal so getting ready to open it up if all else fails. The good thing is the engine is running after a two year lull on the hard at Inverkip marina

 

[Thedigger]

I looked into the peep hole as it was dripping and couldn't see water but it's hard to see it could be I didn't tighten the 3 seven mm bolts on the cover enough.

I have removed the seals from the water pump now I tried to put the seal back in on the impeller side and it refused to go back home. It is 18mm diameter but it feels to small. I the groove where the lip slips in looks too shallow I'm wondering if I have the wrong seal. Gentle tapping and hard hammering it just falls out