1000 Hour service on 6LP

[RicM]

I am just about at the 1000 hour mark on my 03 Yanmar 6LP engine. Also I have sea water leaking from the raw water pump, which indicates (I'm told) that the seal is shot, meaning at least a rebuild, at worst, a new water pump. I would appreciate hearing from any and all that have been through either of these situations. Will I be doing damage by running with the leaky seal? Temps are fine.

[jleonard]

Engine temperature wise you will be ok until the leak gets bad enough to reduce flow...that may not happen.
Eventually the leak will take out the bearing and I'm assuming there is one.
The real problem for me would be the fact that you have salt water slinging around to corrode the neighboring things, including engine parts, pulleys, mounts, etc. whatever is in the way.
I just replaced my generator pump for that reason. I found a very very slow drip and I bit the bullet.

[Carl]

Not sure at all of all of the components, but I do know that the back side of that pump is driven from within the crankcase. So in my mind I would ask myself if the seal failed from age/wear, or has the bearing allowed things to get a bit out of alignment. I the later is the case, I would be concerned about salt water entering the crankcase. Like I said, without looking at the diagragm, I could be way wrong!

[RicM]

I have the pump scheduled to be replaced next week, I'm just trying to figure out if I can run it over the holiday weekend.

[Rx-scape]

This is a common problem, 1st thing they check for on any hr check is if the water pump is leaking, some drip or leak for some time before noticed. It can spray a lot of water and still be used, not good as this is raw water. I replaced mine on 2002 TE 6lp, ordered it one day had it the next and installed it the next morning. NO one was wanting to rebuild the old water pump, just buy a new one
was comment from 3 different mechanics.
Lee Rx-scape

[RicM]

Thanks Lee. How was the job of replacing it? I have an engine box model and it looks like a PITA to get to.....I have a very adept mechanical friend that will help, but I'm not real patient myself.

[RobS]

Replacing the pump is easy. My new pump came without the drive gear. Getting the drive gear off the shaft of the old pump without damaging the gear was a bit of a PITA. You can certainly handle this one Ric, but I'd recommend doing it during a week day so if you need to bring the pump over to one of the mechanic shops to get the gear off you will have that option available to you. Not sure where your leak is, maybe you can address it for the weekend enough to slow it to a minor drip or stop it totally. Obviously if you do use it as is spray the area with freshwater when you get back in and then follow it up with a corrosion x type product.

[Halcyon]

Rebuilding the pump is not hard, but there are a few things to look out for. There are two seals, one to keep the raw water in the pump section and one to keep the oil in the motor. Unless the leak has gone on so long, or the hours are high and the bearings need replacing the seal is easy.
Remover the impeller cover plate and impeller. With a small flat screwdriver, working through the slots in the mid section of the pump, push the seal out. Replace with a new one. You can get these from Yanmar or an industrial supply house. The generic seal number is TCM16x28x7TC. Replace the seal making sure it is seated well and replace.

If your bearings need replacement be careful because there is a small circlip between the two ball bearings. The bearing numbers are 6004 2ZJEM and cost about $25 each. No need to spend $350 for a new pump. Good luck

[RicM]

Got me a pump, last one in the NE from Mac Boring. $479! There is a 3 week wait most places to get from Japan! So I take the thing outta the box and it says "Johnson Pump, Sweden" on it. arrrggghhh. The salt water leaks rapidly when the engine is first turned off (under internal pressure I guess) then slows to a very slow drip when not running for a while. See image. Has anyone found a silver gray hi temp paint the is close to the Yanmar color? I would like to get in there with my new Dremel tool and clean off the rust and spray paint the area.

I will save the old pump and rebuild if necessary in the future. Hey, maybe we should start a core exchange on the BB here...
Anyway, I have all this work to do and the Admiral insists on fishing and going to the fireworks etc. It pains me deeply to run it like this, but temp, water flow, are fine, oil looks fine etc. so I guess it's OK. What pisses me off is that this obviously happened in FL, and the boat sat 3 weeks at a time on blocks. I could have gotten this all done down there.

Got an appointment for the 1000 hour Yanmar service. No lapping of the valves, just valve adjustment, injector pump timing, and pop testing all the injectors...$1100.

[RicM]

Rob and others...

If you replaced the studs for mounting the water pump with bolts..what material did you use? Stainless? Do you remember the size & length?

[craw_daddy]

the biggest killer of those pump seals is high back pressure from the raw water cooling system. This can be caused by blockage of the raw water passages from the internal zincs delaminate within the system (lack of use, not changing zincs frequently enough, small bits of weeds passing through the sea strainer), as well as excessive calcium build-up from not cleaning the heat exchangers thoroughly ~every two years (flushing or removal & cleaning). The heat exchanger with the smallest raw water passages is downstream of the raw water pump -the oil cooler.The other thing that should be done on the heat exchanger cleaning cycle is the replacement of all rubber cooolant hoses, which can get soft & weak over time.

Fortunately, the freshwater coolant system of the 6LP is overbuilt & you generally don't suffer any harm in the event of a raw water failure. As others have mentioned other problems arise from having raw water sprayed around inside near the engine (corrosion of other parts).

[RicM]

I had the raw water system flushed with a ridlyme type solution by my mechanic last season, but that does not preclude high back pressure before that. On the other hand, I did run aground on the ICW in FL over the winter. I used the bow thruster to spin the boat 180 so as not to back through my "sand cloud" but I probably still processed a fair amount of grit through the raw water system. I understand that that can be a big factor in hastening the demise of the shaft and seals as well as scoring the inside of the pump chamber. I have the old pump and will disect with consultants.

[RobS]

...I have the old pump and will disect with consultants.

So the new one is in & done?

[RicM]

Yes, in an intense 3 day turn around we hauled on Tuesday, and Dave yanked the old pump Tuesday AM, but it was too hot to even consider working Tuesday afternoon, so I got up at 5 am Wed and started the wetsand & compound on the hull. Dave started the re-install on the pump and all the hoses, from seacock to strainer to pump, We reused the short hose from pump to heat exchange as it appeared to be a molded special hose. Did you replace? Realizing I needed more arms I hired Dave's son Derek to work with me today and we polished together starting early this AM. Went back in the water around 1:30 PM today (30 pack Bud Lite to the staff does wonders) and everything running good. Hope to get some water time in tomorrow, yard sale at Mom's house Sunday (closing next Friday) then boat to Brewers Cowesett for Yanmar 1000 hour service which will take most of next week. When that's all done I am hoping I will have a Bristol fashion boat in tip top running condition for the trip to Essex and the rest of the season. Oh, got the box of AOG swag for the rendezvous from JC this week, we are going to be stylin' I tells you. Be nice to the Rendezvous Grand Wazoo (me) for an inside line on the good $h!t.

[RobS]

I have yet to replace any cooling hoses but I do check them regularly. I did, however, just remove all of my fuel hoses and cut an inch of them all and reinstalled. I did my Rydlyme flush in Sept 2008. I plan to do it again the end of this season or beginning of next season and change out the hoses on the raw water side. Many of the hoses downstream of the pump will have to be obtained through Yanmar. I can hear me know standing at the parts counter, "but it's just a hose!" This coming winter I plan to change out my raw water seacock as it's getting a bit stiff. I did the 4 smaller ones the first winter. I'll change the 2" raw water intake hoses at that time. You mentioned yours were dry and cracked. After speaking to you about that I did check mine and they appeared okay but if I'm pulling the seacock I will change the hose.