1gm yanmar cooling

[gd7hej]

hi,sat in the harbour with my newly bought yacht,with engine ticking over,waiting for tide gate to open realised no water coming out of exhaust??so took cover off water pump,to find impeller not turning on shaft..i looked at the service history to find out the impeller was fitted about 2 weeks ago,they said they got a yanmar part but would not fit,the part that is fitted is a johnson pump of sweden model 09-1077b-9, is this the correct 1???it will not turn on the shaft at all,can anybody tell me where i can get the correct part,or is it the pump on the yanmar engine,is there a website for yanmars in the uk????please help..regards graham.

 

[pete]

I have same engine and have not had any probs replacing with standard impellor,
A web site I use is http://www.marinedieseldirect.com/yanmar/.
they are quite good for advise and you can get your parts in the UK.
Pete

 

[ccscott49]

The brass/bronze centre of the impellor, where its bonded to the rubber, may have come apart, its quite common on these size impellors, the johnson pump, is the one fitted to your engine, yanmar don't make their own. Is the shaft itself turning?

 

[JimMcMillan]

The impeller on this engine used to last 2 years to the day (almost)but was rectified some 3 years ago and now last much longer.As previous post said the bond between rubber and bush goes.Standard parts are available from Yanmar Dealers, make doubly sure when u refit there are no leaks!!!and carry a spare.This repair was so common that Yanmar sold a kit to convert face plate bolts with thumbscrews.

 

[ccscott49]

You can get those thumbscrews and a plate with "O" ring, from another company, fastseal or something, they advertise regular in PBO and YM. I have them on my mermaids, very good they are aswell! Changing an impellor at sea, you want to do it quickly! I also have a set of Jabsco impellor pullers, which make the job doubly easy, especially in tight places, I used to find it was sometimes quicker and easier to take the pump off some engines, but not in this case.

 

[gd7hej]

hi thank you for info,yes the water pump shaft is turning is there a key to fit in the shaft????key way???

 

[gd7hej]

u must be online at moment...yes the bronze part seems to be in four parts tried squeezing it together and you can see not attached..will yanmar parts cure it??

 

[ccscott49]

Not normally, usually its a flat in the bush and corresponding flat on the shaft, just take it out, all will become plain then. If it has a keyway, not usual, then the key should not shear, it's a sign something else is wrong, never seen a key though. Some have serations, big ones on the shaft, More like a "star drive" but I'm not sure with this engine, usually on bigger impellors. Wheres Paulsjeng? or whatever, he would know.

 

[brian_neale]

The water pump shaft on this engine has a flat, with a corresponding flat in the bush in the centre of the impeller. I have had two impellers fail in about 8 years, both only a few weeks or so after fitting. I reached the point where I had two or three new impellers on board, plus a couple of old ones which were working when I changed them, plus three or four pump gaskets, plus a set of spare bolts in case I lost one when changing an impeller in a hurry. Grease the gasket well when refitting and the gasket will then last for several impeller changes.

My local dealer from whom I always bought my spares changed the old impellers without question; according to Yanmar there were a couple of bad batches a few years ago. As already mentioned, the failure was the bond between bush and impeller.

I also had a seal fail in the pump, and was able to buy the components to rebuild it at much lower cost than buying a new pump

 

[Guest]

Can you tell me, has your pump spindle got a key or a slot in it, because johnson make 2 different types and even Yanmah dont know what type was fitted to the engines. I recently had the same problem on a 3GM30. I got what was listed as the correct impellor for the engine only to find that I had been given a keyed shaft type when in fact mine was the type that needs a screw through the impellor. dispite my taking it back the agent said that he had given me the correct type for that engine/year and proceeded to show me the manuals. Bottom line is open your pump, check brass insert on the impellor if it has a key way in it check if you have a slot in your drive shaft if you have you need to simply change the impellor for correct type

 

[vyv_cox]

3gm yanmar cooling

My 3GM30F bought January 2001 has the slotted type of impeller drive.

A couple of comments on the thread

- it would be very difficult indeed to change the impeller in a hurry in my installation. The pump is mounted below the main pulley and it faces back, so the screws holding on the top plate need to be undone blind with the handle away from you. I found it much easier to remove the pump first but this takes a few minutes.

- after 1 year of use, just over 100 hours, the old impeller was deeply split. Definitely a job that needs to be done every year.

 

[Ralph]

I have a YSE12 engine which is similar though horizontal. I have a friend with YGM10 and his water pump is virtually the same as mine. I completely rebuilt mine recently. I took it to a engineering bearings supplier and managed to buy the double lipped seal and the two bearings at a small fraction of the cost from Yanmar. I replaced the standard cover with a 'speed seal' earlier discribed on this thread. If you search for speed seal in google you should be able to find it. My water pump is fixed and tensioned with two easily removed bolts. If in doubbt remove the pipes and take the pump off and take it to any chandlers. They mostly sell the Jabsco impellors which are probably the same ones that Yanmar sell in 'costalot' packaging. They are easy to fit and you should carry at least one spare on board at all times. Gaskets and screws are bad news on a lumpy sea so I would strongly recommend a 'speed seal'. Make sure you have a pot of waterproof grease on board as well. It holds the 'o' ring in position on the 'speed seal' cover when you remove it. The water pump is vital but easy to work on.

 

[Ralph]

I have a YSE12 engine which is similar though horizontal. I have a friend with YGM10 and his water pump is virtually the same as mine. I completely rebuilt mine recently. I took it to a engineering bearings supplier and managed to buy the double lipped seal and the two bearings at a small fraction of the cost from Yanmar. I replaced the standard cover with a 'speed seal' earlier discribed on this thread. If you search for speed seal in google you should be able to find it. My water pump is fixed and tensioned with two easily removed bolts. If in doubbt remove the pipes and take the pump off and take it to any chandlers. They mostly sell the Jabsco impellors which are probably the same ones that Yanmar sell in 'costalot' packaging. They are easy to fit and you should carry at least one spare on board at all times. Gaskets and screws are bad news on a lumpy sea so I would strongly recommend a 'speed seal'. Make sure you have a pot of waterproof grease on board as well. It holds the 'o' ring in position on the 'speed seal' cover when you remove it. The water pump is vital but easy to work on.

 

[Guest]

Re: 3gm yanmar cooling

vyv, I agree with you to change the impeller on our 3GM30 engines is best done by removing the pump from the engine, doesn't take a couple of minutes. In our club we have 2 of these engines, 1 freash water, 1 raw water and although they have the same pump set up both impellers are different on the drives, 1 is slotted shaft with screw drive and the other is key driven.

 

[JimMcMillan]

Yes!and if the "O"ring is suspect Halfords sell a pack of 2/3 that do the job.best of luck.

 

[brian_neale]

One source of confusion here may be that on the 1GM there is only one sea water pump (flat on spindle - never been offered any alternative) whereas on the 20F/30F freshwater cooled variants there are two pumps - one for fresh and one for sea water. The sea water pump may well vary as this is fitted externally to the engine and belt driven. The freshwater pump is driven directly from the engine, and I would expect this one to be a "flat on a shaft". I shall have a 3GM30 in the new boat, but raw water cooled - fewer bits to leak/go wrong!

 

[vyv_cox]

3GM yanmar cooling

I don't think the fresh water pump on the 3GM30F will have a rubber impeller - it looks like a typical cntrifugal car type pump to me. It would appear from the correspondence on this thread that at least two impeller types have been fitted to these engines. Only matching like with like will do!

I shared your view on the fresh/sea water cooled options. I fully intended to have the sea water version, having had good experience with Bukh and knowing some of the problems experienced by professional users of fresh water cooled Volvos. However, I was persuaded to have the fresh water version, partly because of improved calorifier performance, and I must say I don't regret it at all. The unit has so far been completely reliable and there seems little extra that can go wrong.