Questions about internal anodes

[Yammie70]

Hi everyone,

I have an 70BET0 from 97 which is working fine but has a very weak water flow through the telltale.
The thermostat and water pump are new and working fine, so I suspect the water passage a blocked by salt build up over the years (although I always flush my motor with freshwater, I don't how the previous owner looked after it).
I've removed the lower unit and circulated some Rydlyme though the water cooling system a few months ago, it improves the flow a little bit but nothing impressive.
Yesterday, when I tried to start the motor and the water was not running at all. The telltale was blocked by a big chunk of salt/crud build up that I managed to remove with a wire.
I plan to do another rydlyme treatment over the weekend to see if I can cleanup a bit more...

Now, I just became aware of the existence of internal anode (part 17 on this page: https://www.crowleymarine.com/yp/T8W...ha-70beto-2017) and have a couple of questions:

- How often these should they be inspected / replaced ? I don't think they have ever been replaced and couldn't find any information about these.

- It's hard to see on the diagram, but I imagine these anodes are in contact with the water flowing through the cooling system. Is this correct ? I'd like to know this because, I think the rydlime could damage them if they are in contact, it's probably a good idea to remove them first...

- Is there any other option to clean up the water passage ? (other than removing the cylinder heads + exhaust cover to clean it manually)

Thanks a lot your inputs!

[99yam40]

If the rydlime does not clear it, the removal of parts and manual cleaning is all that is left to do.
you can inspect the anodes if you take it apart

how long did you circulate it last time?
did you remove the stat?

I dropped the lower unit on my brothers C60, pulled the stat, and hooked up a water hose to the tube headed to the power head,
turned water on full blast to flush the motor and then injected compressed air into the water hose going to the tube from time to time to help flush stuff out.
the air and water surging will help move things around and hopefully out of the motor.

if done on a clean concrete slab or drive way you can see the stuff that gets dislodged and coming out
or catch as much of the water in a tub to inspect once done and drained

[TownsendsFJR1300]

The anodes will help prevent corrosion to the block but salt will still accumulate in the block. Especially after numerous cycles of turning off a hot engine, the salt bakes on.

I flush regularly as well but the salt is still there, baked on..

As 99Yam posted, manually cleaning the cooling passages should solve your issues. Pretty much just removing the head, then manually removing the crud..

You'd be surprised how much salt build up there is but the engine still runs good(no alarms, still pissing, etc).

[Yammie70]

If the rydlime does not clear it, the removal of parts and manual cleaning is all that is left to do.
you can inspect the anodes if you take it apart

how long did you circulate it last time?
did you remove the stat?

I dropped the lower unit on my brothers C60, pulled the stat, and hooked up a water hose to the tube headed to the power head,
turned water on full blast to flush the motor and then injected compressed air into the water hose going to the tube from time to time to help flush stuff out.
the air and water surging will help move things around and hopefully out of the motor.

if done on a clean concrete slab or drive way you can see the stuff that gets dislodged and coming out
or catch as much of the water in a tub to inspect once done and drained

- did exactly the same with the lowed unit out lasttime and let it run for 4-5hours. Lots of stuff came out and the water flow was a bit better.
The Tstat was out but I've never touched the internal anode. I thought this treatment might have broken the anode into piece and block the water passage...

I'll remove the anode and inspect them, flush once more with rydlime with the Tstats and anodes out. Put back everything back and if it still doesn't work, I'll have to pull the head cover out.

It doesn't look complicated but I'm a bit scared of breaking bolt on a 20years+ motor used in saltwater...

Thanks for your help

[robert graham]

I'd definitely be concerned over breaking bolts on a 20 year old saltwater motor...maybe a chemical clean with motor running is still the best route to take?

[pstephens46]

I'd definitely be concerned over breaking bolts on a 20 year old saltwater motor...maybe a chemical clean with motor running is still the best route to take?

Yep. Bolts might be fun

[99yam40]

- did exactly the same with the lowed unit out lasttime and let it run for 4-5hours. Lots of stuff came out and the water flow was a bit better.
The Tstat was out but I've never touched the internal anode. I thought this treatment might have broken the anode into piece and block the water passage...

I'll remove the anode and inspect them, flush once more with rydlime with the Tstats and anodes out. Put back everything back and if it still doesn't work, I'll have to pull the head cover out.

It doesn't look complicated but I'm a bit scared of breaking bolt on a 20years+ motor used in saltwater...

Thanks for your help

did you use some compressed air like I mentioned to help stir things up?

is it just the tell tail being weak that is a problem?
or do you have a overheat also

[99yam40]

I'd definitely be concerned over breaking bolts on a 20 year old saltwater motor...maybe a chemical clean with motor running is still the best route to take?

Robert, Rydlime is a chemical cleaner, and he said he ran it thru for 4 - 5 hours.
but doing it again might do some more cleaning

[robert graham]

Yep, the last thing he probably needs is some nightmare situation with broken head bolts......I've run my motor in a 55 gallon drum with fresh water while adding 2 or 3 quarts of muriatic acid and it was easy enough to see the mineral deposits coming out and floating as a foam on the surface of the water.....after an hour or so I added bicarbonate of soda to neutralize the acid....The heat from the exhaust will heat the water/acid mixture making it more active and remove deposits better and as long as the solution is moving/circulating then the possibility of metal damage is minimal.....the e bicarbonate neutralizes the acid....

[TownsendsFJR1300]

Is there any reason why you couldn't do the Rydlyme treatment W/O removing the LU?

IE, use the flush port hose to pump Rydlyme water in (still remove the thermostat) and have a catch pan large enough to catch all out coming water to pump back into the engine?

Saves removing the LU, cleaning fluids gets into the LU as well removing salt/crap from there as well..

Thoughts?

[Ferris11]

I used the same method as Robert did on my 2006 f90tlr motor last year but I used "salt-away". I used a gallon of "salt-away"in a large 60 gallon poly container with 50 gallons of fresh water and lowered the motor into it so that the lower unit was halfway sumerged. I ran the motor about 1 1/2 hours and I only stopped because I felt that the water was starting to get too hot. I did notice a small amount of grit at the bottom of the container but since I run my boat in a bay mostly with brackish water I really didn't think that I would flush much out anyway. I did want the circulating mixture to flow through the whole motor and I did want the temp of the water do get semi-hot because salt does dissolve faster in hot water.

[Yammie70]

Hi,
Thanks everyone for the help.
I've bought another bottle of Rydlyme, remove the Tstats, lower leg. Put 5L (50% Rydlyme, 50% water) into a bucket and used a pond pump to circulate the mix for ~2.5hours.
This has unblocked the passage and flow is much better than before...I'm going for a test run tomorrow but I think I'm good to go until this happened again (hopefully not too soon).

[99yam40]

good to hear.
did you pull the lower and stats the 1st time or was that just this time?

[Yammie70]

good to hear.
did you pull the lower and stats the 1st time or was that just this time?

Yes I've followed exactly the same process last time.

[99yam40]

well same procedure but different results must mean it finally got the passage that was causing the problem cleaned.
I guess it was not run long enough the 1st time or the cleaner got used up and the fresh stuff took care of your problem