25D Stuff #2 (1GM10 FUN)

[Lou Ostendorff]

Time for installment #2, but before the specifics, a little poem...

My boat has a problem,
What should I do?
Try readin' this board,
You may get a clue...

So many had questions,
And the answers weren't here,
They posted a message,
To make the problem clear,

After a while,
Several readers responded,
And among the 'solutions'
Was one that was wanted...

By continuing in this fashion,
The database would grow,
and by 'readin' the threads'
You learn what others know...

And now, for a Zinc story...After aquiring KARMA, I naturally wanted to know EVERYTHING about her, including the recently installed 1GM10 Yanmar Diesel, with only 65 total hours on it (according to the hour-meter). I read everything on this board, as well as several places on the Internet, about changing the 'engine zinc', but could not find out specifically where it was or the frequency/procedure in changing it. I finally bought the Yanmar Service Manual (A0A1361) from Mack Boring, the East Coast Distributor (www.mackboring.com). The referenced manual covers the 1GM10 thru 3GM35 models, and can be had for the princely sum of about $41 US. Now having the 'source' of all known information on this mechanical marvel, I commenced to ciphering on the problem, and found the section on replacing the zincs...the manual states that they should be replaced about 'every 500 hours of operation'...well, that's a stretch. To get to the zinc, you have to remove either the alternator or the starter. I chose the alternator, as this would force me to retighten the belt (normally a good thing).
Two bolts hold a diamond shaped plate on, into which the zinc is screwed into, and locked down with an external nut... to my suprize and subsequent disbelief, the zinc was totally consumed, and in its place, a white spongy mass! Soooooo, something else be goin' on dude!
Which led me to my second bit of education, that of galvanic corrosion, how it works, and how to stop and/or deal with it...well, I couldn't resist buying another book about it, and reading some more Internet stuff, but the long and short of it is, a few obvious factors govern the speed of consumption...the salinity of the water, the amount of running time of the engine, which passes water over the zinc, the bonding in the boat, and finally, whether you're in a marina and hooked up to shore power. I can't explain exactly what's happening in KARMA, but I suspect that the engine zinc is protecting more than just the engine...maybe all the noble metals on the boat, sharing the common bonding. If this is the case, I will have to spend some more time isolating exactly what it SHOULD protect, and let the donut zinc on the shaft protect the rest. My advice to you, is that you check your engine zinc often, and come up with a workable schedule for checking/replacing it. Once it's gone, the other metals in the engine begin to deteriorate, and that gets expensive...

More to follow in Installment #3



louosten@ipass.net

[Bob Ohler]

OK....Here's how you change the internal engine zinc on a Yanmar 1GM.
You DON'T have to remove the starter or alternator! Remove the alternator belt. Loosen the alternator bolts, swing the alternator up as far far as it will go, and snug one alternator bolt to hold it there. Now, with a 1/4" drive ratchet, and a 10mm shallow socket remove the hex head bolt closest to you. For the bolt that is farthest from you, the same ratchet and socket go up and over the alternator, and you come at the bolt form the "other" side. You can prop a flashlight on the side of the engine and this will give you light for the bolt in the back.
Now disassemble the plate and old zinc. Scrape and clean the plate. Assemble a new zinc to the plate, but be sure to use a small neoprene gasket behind the zinc to prevent it from leaking around this center stud. If you need a new gasket, apply a thin layer of grease (it's sticky!) to the plate to hold the gasket in place. Now, re-insert the assembly and get the front "easy" bolt first, but do not tighten it. Now go for a walk, take a deep breath, and come back hand install the rear bolt by hand until it so tight that you need the ratchet th tighten the bolts EVENLY. It sounds tougher than it is. The first time it may take you an hour. But once you do it, it will get easier. The entire process takes me about twenty minutes. Have the new zinc, the new gasket, and the ratchet and the grease ready before you start.
I change mine once a year... I guess because I know how to do it
now.
If you still can't do it, drop me a line.
Good luck!
Bob Ohler
Cape Dory CD25D, Hull #2!
sv "Aloha Spirit"



bobohler@chesapeake.net

[Dan VanWinkle]

Bob, you must be right! Cause that's the way I do it! Glad to see you are alive and well. Now if you could just describe the method for servicing the "seacock from hell"-the port side cockpit one that's almost impossible to see or reach. At least that's the way it is on my boat. Dan "Bali Ha'i" CD25D #69

OK....Here's how you change the internal engine zinc on a Yanmar 1GM.
You DON'T have to remove the starter or alternator! Remove the alternator belt. Loosen the alternator bolts, swing the alternator up as far far as it will go, and snug one alternator bolt to hold it there. Now, with a 1/4" drive ratchet, and a 10mm shallow socket remove the hex head bolt closest to you. For the bolt that is farthest from you, the same ratchet and socket go up and over the alternator, and you come at the bolt form the "other" side. You can prop a flashlight on the side of the engine and this will give you light for the bolt in the back.
Now disassemble the plate and old zinc. Scrape and clean the plate. Assemble a new zinc to the plate, but be sure to use a small neoprene gasket behind the zinc to prevent it from leaking around this center stud. If you need a new gasket, apply a thin layer of grease (it's sticky!) to the plate to hold the gasket in place. Now, re-insert the assembly and get the front "easy" bolt first, but do not tighten it. Now go for a walk, take a deep breath, and come back hand install the rear bolt by hand until it so tight that you need the ratchet th tighten the bolts EVENLY. It sounds tougher than it is. The first time it may take you an hour. But once you do it, it will get easier. The entire process takes me about twenty minutes. Have the new zinc, the new gasket, and the ratchet and the grease ready before you start.
I change mine once a year... I guess because I know how to do it
now.
If you still can't do it, drop me a line.
Good luck!
Bob Ohler
Cape Dory CD25D, Hull #2!
sv "Aloha Spirit"

[Bob Ohler]

Dan, my dear friend Mitchell Bober coined the expression that Cape Dory employed War Criminals to determine the placement of the seacocks. Ever since I heard him say that, I have to laugh everytime I think about servicing the ones on my boat.
Dan, some people think it is a waste of money, but the seacock wrenches that Spartan sells makes the job a whole easier. I even think that their grease is smoother than other stuff that you buy, but I know that Spartan is not making the stuff themselves, so someone's grease must be just as good as Spartans. I think that the port side scupper seacock may be one that you take apart not all at once, but in stages. Seems to me, that that is the one that I loosen the nut but I can't remove it completely. I then back out the barrel of the seacock and then remove the nut. Of all the spring maintenance, for some reason it is the seacock servicing that I find it the most difficult to get enthused about. But I still manage to get them done each year. I've got 2 done, and I'll do the other 3 next trip to the boat. "Splashdown" is 4/6 for the Aloha Spirit! Hope all is well with the Bali Hai crew!

Bob, you must be right! Cause that's the way I do it! Glad to see you are alive and well. Now if you could just describe the method for servicing the "seacock from hell"-the port side cockpit one that's almost impossible to see or reach. At least that's the way it is on my boat. Dan "Bali Ha'i" CD25D #69

OK....Here's how you change the internal engine zinc on a Yanmar 1GM.
You DON'T have to remove the starter or alternator! Remove the alternator belt. Loosen the alternator bolts, swing the alternator up as far far as it will go, and snug one alternator bolt to hold it there. Now, with a 1/4" drive ratchet, and a 10mm shallow socket remove the hex head bolt closest to you. For the bolt that is farthest from you, the same ratchet and socket go up and over the alternator, and you come at the bolt form the "other" side. You can prop a flashlight on the side of the engine and this will give you light for the bolt in the back.
Now disassemble the plate and old zinc. Scrape and clean the plate. Assemble a new zinc to the plate, but be sure to use a small neoprene gasket behind the zinc to prevent it from leaking around this center stud. If you need a new gasket, apply a thin layer of grease (it's sticky!) to the plate to hold the gasket in place. Now, re-insert the assembly and get the front "easy" bolt first, but do not tighten it. Now go for a walk, take a deep breath, and come back hand install the rear bolt by hand until it so tight that you need the ratchet th tighten the bolts EVENLY. It sounds tougher than it is. The first time it may take you an hour. But once you do it, it will get easier. The entire process takes me about twenty minutes. Have the new zinc, the new gasket, and the ratchet and the grease ready before you start.
I change mine once a year... I guess because I know how to do it
now.
If you still can't do it, drop me a line.
Good luck!
Bob Ohler
Cape Dory CD25D, Hull #2!
sv "Aloha Spirit"

bobohler@chesapeake.net

[Dan VanWinkle]

Thanks for the encouragement. I do have the Spartan wrench-discovered last year and treasure it greatly. As for the subject port side seacock. Seems to me that last year I discovered that at one stage in reassembly I could get the nut on by alternately holding it and turning the seacock itself. It worked like a charm but was still hard to get both hands in the right position.

Have plans to join you all at Cambridge this year.
Bali Ha'i CD25D #69

Dan, my dear friend Mitchell Bober coined the expression that Cape Dory employed War Criminals to determine the placement of the seacocks. Ever since I heard him say that, I have to laugh everytime I think about servicing the ones on my boat.
Dan, some people think it is a waste of money, but the seacock wrenches that Spartan sells makes the job a whole easier. I even think that their grease is smoother than other stuff that you buy, but I know that Spartan is not making the stuff themselves, so someone's grease must be just as good as Spartans. I think that the port side scupper seacock may be one that you take apart not all at once, but in stages. Seems to me, that that is the one that I loosen the nut but I can't remove it completely. I then back out the barrel of the seacock and then remove the nut. Of all the spring maintenance, for some reason it is the seacock servicing that I find it the most difficult to get enthused about. But I still manage to get them done each year. I've got 2 done, and I'll do the other 3 next trip to the boat. "Splashdown" is 4/6 for the Aloha Spirit! Hope all is well with the Bali Hai crew!

Bob, you must be right! Cause that's the way I do it! Glad to see you are alive and well. Now if you could just describe the method for servicing the "seacock from hell"-the port side cockpit one that's almost impossible to see or reach. At least that's the way it is on my boat. Dan "Bali Ha'i" CD25D #69

OK....Here's how you change the internal engine zinc on a Yanmar 1GM.
You DON'T have to remove the starter or alternator! Remove the alternator belt. Loosen the alternator bolts, swing the alternator up as far far as it will go, and snug one alternator bolt to hold it there. Now, with a 1/4" drive ratchet, and a 10mm shallow socket remove the hex head bolt closest to you. For the bolt that is farthest from you, the same ratchet and socket go up and over the alternator, and you come at the bolt form the "other" side. You can prop a flashlight on the side of the engine and this will give you light for the bolt in the back.
Now disassemble the plate and old zinc. Scrape and clean the plate. Assemble a new zinc to the plate, but be sure to use a small neoprene gasket behind the zinc to prevent it from leaking around this center stud. If you need a new gasket, apply a thin layer of grease (it's sticky!) to the plate to hold the gasket in place. Now, re-insert the assembly and get the front "easy" bolt first, but do not tighten it. Now go for a walk, take a deep breath, and come back hand install the rear bolt by hand until it so tight that you need the ratchet th tighten the bolts EVENLY. It sounds tougher than it is. The first time it may take you an hour. But once you do it, it will get easier. The entire process takes me about twenty minutes. Have the new zinc, the new gasket, and the ratchet and the grease ready before you start.
I change mine once a year... I guess because I know how to do it
now.
If you still can't do it, drop me a line.
Good luck!
Bob Ohler
Cape Dory CD25D, Hull #2!
sv "Aloha Spirit"