Yanmar 3QM30F Serial Number location? Raw Water Pump Problem...

[JohnnyB]

Hola Friends....

After a month in the Exhumas, we are now stuck in Nassau with a water pump">raw water pump problem on our 1985 Tayana 37.

I rebuilt the pump, replacing seals, bearings, and shaft in March, and have put 200 hours on it. Now, I find the weep hole leaking seawater at 1500 rpm and above.

I will rebuild it again, replacing the seals. The yanmar distributer back home needs the serial number of the Yanmar 3QM30F to check availabilty and price a new pump. He said there were several pumps put on this moter. Mine does not have the bilge pump option, but he tells me he needs the serial number and I can't seem to find it.

Anyone have any ideas?

Thanks...JohnnyB

[JohnnyB]

Anyone have any ideas as to why the raw water pump failed again after 200 hours?

Thanks...

JohnnB

[Whimsical]

What condition was the shaft in? Only 200 hours something must have chewed them out.

Mike

[JohnnyB]

NOPE Yanmar is telling me that I still need the serial number....Any ideas as to location?

Mike the shaft was new 200 hours ago at the rebuild...I replaced it.

[JohnnyB]

Could it be a back pressure problem? I can blow through the exhaust and force water out with lung power, does that matter?

JohnnyB

[GordMay]

Most Yanmar engine model designations are on an engine data plate, on the front or the top of the engine. Some older engines have the data plate on the adapter plate between the engine and the gearbox .

[Chief Engineer]

Your Parts guy is a mo-ron.

I see this all the time, where the parts places rely on computers to look up a part.

You ask to see a parts BOOK/CATALOG and they look at you the same way a Labrador looks at you when you talk to it.

Depco Pump Company

[Chief Engineer]

were installed backwards. In other words....the open side of the seal, that has the tiny spring in it is located on the pressure side.
The pressure causes the lip to securely contact the shaft.
The seal is driven in from the flat side.

Originally Posted by JohnnyB

Anyone have any ideas as to why the raw water pump failed again after 200 hours?

Thanks...

JohnnB

[zippy]

I just rebuilt my water pump with all new bearings & seals and it leaked out the back again when I first used it, about a drop a second. I put the open side of the water seal with the small spring facing the impellor. I wasn't sure if that was the correct direction. Now that Chief Engineer has explained that I have it on correctly, there must be another reason for the leak.

Could wear on the shaft be the problem? That would be diifficult to prove without replacing the shaft.

[JohnnyB]

I am 90% sure I put the spring side away from the impeller...Is that correct? Anyway, as chief engineer, please clarify.

Still waiting on parts....I am threatening to put my wife to work here in Nassau to pay for my marina bill.

JohnnyB
Sv Jackaby

And I still can't find a DATA PLATE!

[Chief Engineer]

is to have you look at the front of your engine. Around the crankshaft/behind the pulleys is an oil seal. Commonly called a front main seal. If you observe it, you will notice that it is a solid ring. The open side with the spring (tiny) is on the back side.

I hope the following (using keyboard symbols) helps

[ = oil seal with solid side on left
] = oil seal with solid side on right


oil pressure from engine ] outside engine air pressure

outside aire pressure [ raw water pressure inside impeller pump

on some pumps you will see this
oil pressure ] [ internal impeller pump pressure

[zippy]

Thanks for the clarrification. When trying to reason out the answer to the seal direction, my concern was that the spring would corrode when exposed to the salt water side of the pump. I had the same question when replacing the seal on the hand pump for the head.

After seeing the condition of these springs when removed I now know that they were in the correct position and they do corrode quite quickly.

[Inlet Marine Services]

Johnny, I am a Yanmar dealer. The part number for the pump for a 3qm30 is 724770-42702. There is not a 3qm30f there is a 3gm30f. The pump list price is $ 540.18 They are in stock in Chicago, ILL.

[JohnnyB]

THey quit making her back in the early 80's, I believe. THanks though, for trying.

[GordMay]

Yanmar’s QM series was produced from 1976 to 1980, when the GM/HM Series was introduced.
The QM series was available either sea-water or fresh-water cooled ( 3QMF= Factory Fresh Water).

Online parts catalog for the Yanmar 3QM, from Yanmar catalog #Y00R0919:
Torresen Marine