Salt Build up in Suzuki Powerheads

[a64pilot]

The thing is, and I assume it’s correct is that we aren’t looking at salt, which is water soluble, we are looking at essentially Limestone which really isn’t very water soluble at all.
Other than acid, I know of nothing that will remove limestone except physically digging it out, and acid also removes aluminum too.

I know of Salt away, but have never used it, so I don’t know what it even is.
I know of CLR, have used it on bathrooms etc and found it to not do much of anything at all, even when a shower head was soaked in it overnight.

Now I normally always warm an engine up slowly, and allow one to cool down slowly before shut down, that has been beaten into my head forever.
Lawnmowers to aircraft it doesn’t matter.
So maybe that has contributed to near as I can tell that I have no build up?
However I still think it’s temp related, or raw water cooled engines would have 195f thermostats, and they don’t.

[ranger58sb]

Originally Posted by a64pilot

The thing is, and I assume it’s correct is that we aren’t looking at salt, which is water soluble, we are looking at essentially Limestone which really isn’t very water soluble at all.
Other than acid, I know of nothing that will remove limestone except physically digging it out, and acid also removes aluminum too.

I know of Salt away, but have never used it, so I don’t know what it even is.
I know of CLR, have used it on bathrooms etc and found it to not do much of anything at all, even when a shower head was soaked in it overnight.

Now I normally always warm an engine up slowly, and allow one to cool down slowly before shut down, that has been beaten into my head forever.
Lawnmowers to aircraft it doesn’t matter.
So maybe that has contributed to near as I can tell that I have no build up?
However I still think it’s temp related, or raw water cooled engines would have 195f thermostats, and they don’t.

I mentioned I used water for my normal pre-event flushing. Afterwards, I've used Salt Away... once. That was after learning from the dealer that's what they use... and that's what didn't work for them on our motor, prior to manually cleaning all that stuff out. They called it salt, it looked like salt, so I've called it salt... but I don't really know what the stuff really was.

I've used Barnacle Buster and Rydlyme to clean engine and genset raw water systems. The generator actually needed it, and the stuff (Rydlyme, that time) seemed to work great. Didn't see any difference on the mains, but I didn't actually open those heat exchangers, aftercoolers, oil coolers, etc. for eyeballs on before or after.

I've also used BB on the AC raw water system, but dunno what gets in there, either. I'd guess mostly mud and slime, so fresh water might be just about as effective.

Both BB and Rydlyme are (different) acidic dilutions

Dunno metals inside the Suzuki DF15a, Aluminum likely all over casings and so forth, but other than that...?

-Chris

[a64pilot]

So how do people use these flushes?
I’d assume you put the motor is a 5 gl bucket and run it, that way recirculating the BB, Rydlime or whatever?

[Captain Bill]

A64, I am one of the people that have had the problem with my 5 year old DF15A. The first time it happened was in December of 2016. I had been in a marina for about a month, did an oil change and took it out for a test run before heading to the Bahamas. It promptly overheated and I limped back to the boat. I first thought that the impeller was shot and pulled it, but it looked fine. I then removed the thremostat and it was covered in some sort of crystalline deposit so I replaced it, still overheated. I took it to a Suzuki shop where they told me it was totally clogged with salt deposits. About $300 later it was declared salt free and returned to service. From the barrel and empty jug that was nearby when I picked it up it looks like they ran it in a barrel with something called saltaway or something like that. About a year later after 2 months on the had in a boatyard the problem occurred again. This time the first thing I did was remove the thermostat and sure enough more crystalline deposits. I was in no position to get it to a dealer and had no barrel to run it in myself, so I removed the internal zinc and sprayed phosphoric acid into the head. I flushed it using my saltwater washdown as that was all I had. A tremendous amount of stuff came out of that head when I flushed it. After four spray downs and flushings no more deposits were visible. I had the problem again last summer again after a boat yard stay of about 6 weeks. The pattern seems to be that it only occurs after a long period of inactivity. I'm wondering if the head fails to drain and the saltwater sitting in the head reacts with the head metal. This winter I had a planned 2 month stay in a marina so the first thing I did was hook up the motor to the flushing unit and ran it for 3 hours with fresh water. It did not have a problem when placed back in service at the beginning of this month, but then again it has only been 6 months since its last cleaning.

I tested the thermostats. Of course the ones with the deposits didn't work until they were cleaned, but after they were cleaned they worked normally and opened at the correct temperature which if I remember correctly is 140f.

One thing I noticed is that my warranty specifically excludes corrosion damage from use in salt water.

[ranger58sb]

Originally Posted by a64pilot

So how do people use these flushes?
I’d assume you put the motor is a 5 gl bucket and run it, that way recirculating the BB, Rydlime or whatever?

I used the bucket when I flushed with SaltAway before winterizing this year. It helps to use something wide enough to catch and recirculate fluid from the telltale -- or rig a temporary guidance tube or something. The dealer keeps a tank permanently set up for that, so that's how they did it too... prior to tearing it down and manually de-gunking.

For BB or Rydlyme on other systems, I've taken two approaches: full recirculation, and fill-wait-flush. Didn't see any difference in the outcome from those two different systems. I've not used BB or Rydlyme on the outboard. (Yet?)

-Chris

[thinwater]

Originally Posted by catsketcher

Thinwater - where does the calcium and magnesium come from? What is the deal with the critical temperature? 30 years ago it seemed like a salty crusty crystalline substance when I pulled the cooling jacket off but we didn't taste it.

Anything else you can elaborate on, please do.

cheers

Phil

We think of seawater in terms of salt, but in fact, seawater is also very, very hard, with calcium and magnesium near saturation. That is why coral grows well. Yes, it will be crusty and crystalline. Obviously, if it was actually sodium chloride salt, it would dissolve back into the water.

With salt, the hotter the water, the better it dissolves. With calcium the reverse is true; when the water gets hot it crystallizes out. A well known problem in cooling towers and boilers. This is also why lime build up is VERY sensitive to thermostat setting and hot spots within the engine.



PS did tests of scale removers last year, comparing how much lime they removed per time AND how much damage they did to various metals at the same time. Although not the fastest products, CLR had the BEST ratio of lime removal to aluminum damage of the lot. Obviously, aluminum corrosion during cleaning/flushing is related to time an concentration. No free lunch. But with CLR the damage to the aluminum was trivial. As I recall, Barnacle Buster was nearly as safe and faster.

[rbk]

Originally Posted by thinwater

We think of seawater in terms of salt, but in fact, seawater is also very, very hard, with calcium and magnesium near saturation. That is why coral grows well. Yes, it will be crusty and crystalline. Obviously, if it was actually sodium chloride salt, it would dissolve back into the water.


With salt, the hotter the water, the better it dissolves. With calcium the reverse is true; when the water gets hot it crystalizes out. A well known problem in cooling towers and boilers.

Or simply take a look in any electric kettle or coffee maker.

[Captain Bill]

Sorry to have to come back to this thread. I am still having trouble with my DF15A overheating. Last fall I flushed it in a barrel for 3 hours with diluted phosphoric acid recirculating. The water in the barrel got pretty hot but the overheat warning never got triggered. I flushed it for an hour with clean fresh water afterwards. It's about a 30 minute run from the boat ramp to my boat. I put it back in the water and ran back to my boat with no problem. I put it on the davitsand flushed it with fresh water while hanging on the davits. About a month later I dropped it in the water and it overheated before I got out of the idle speed only area of my canal system. I figured the high temp. of the water might have eaten the water pump so I pulled that. No vanes missing and it still seemed flexible, but since I already had the kit I changed it anyway. It still overheats. I bought a Suzuki diagnostic software kit which said it had the service manual for the 2014 EFI version of the DF15a. They lied. It only had the manual for the carbureted version. It confirmed overheating and when I watched the temperature as the engine warmed up it looked like I would expect with the temperature rising over time until it hit 80C and the overheat warning triggered, so it doesn't seem to be a bad temp sensor. I pulled the thermostat today and heated it in a pan of water and it started opening at 136Fand was fully open by about 142 which is in spec. I pulled the zinc cover off as well and flushed he head. The thermostat opening had significant salt deposits while the zinc opening was very clean. I put the hose in the flush fitting and water flowed freely out of the zinc hole and out of the bypass(?) hole in the thermostat housing, but no water at all came out of the thermostat hole. Looking at the waterflow diagram in the manual I have part of the flow that goes through the heat goes out the pee hole and part goes to the thermostat. The engine has always had plenty of water coming out of the pee hole. I assume (I know) that the water that is coming out of the hole into the thermostat housing is the water that is supposed to go from the head to the thermostat housing in the diagram. Water is also supposed to go through the oil pan to the thermostat and then back through the oil pan and out the exhaust. Unfortunately something in the cooling system must have changed between 2013 and 2014 because the 2013 diagram describes a cooling water hose after the thermostat but there doesn't seem to be any such item on my engine. I am assuming that no water or very little gets to the back side of the thermostat and I must have a clog in the system between the water pump and the thermostat but after the flow is split off for the thermostat channel. Does anyone have a diagram of the water flow in a 2014 or newer DF15a or the 9.9 or 20 hp versions as they use the same power heads. It's pretty clear to me that none of the things done by me or professional mechanics has done much to the clog as it clogs in relatively short order.

[a64pilot]

What are the symptoms of an overheat?
I ask as mine has very recently cut and run on one cyl. When running low speed just putt putting around. At the time I thought it was fuel starvation as I had had it off and serviced it, oil change, gear case oil change etc and my primer bulb is I think defective, I think one of the valves is in the bulb so it doesn’t work.
Anyway I got the red LED, Mickey Mouse primed the fuel bulb by kinking the hose to make it work like a valve and it hasn’t returned, but wondered how you know it’s an overheat?

However it runs fine at full bore and for extended intervals so I can’t imagine I have a restricted water passage.

[Captain Bill]

Originally Posted by a64pilot

What are the symptoms of an overheat?
I ask as mine has very recently cut and run on one cyl. When running low speed just putt putting around. At the time I thought it was fuel starvation as I had had it off and serviced it, oil change, gear case oil change etc and my primer bulb is I think defective, I think one of the valves is in the bulb so it doesn’t work.
Anyway I got the red LED, Mickey Mouse primed the fuel bulb by kinking the hose to make it work like a valve and it hasn’t returned, but wondered how you know it’s an overheat?

However it runs fine at full bore and for extended intervals so I can’t imagine I have a restricted water passage.

I got the overheat alarm condition of the computer diagnostics. I was beginning to think it was something else until I got the diagnostic kit and hooked it up to the computer. The last three times I ran it I got the red light and limp home mode and sure enough the computer said for the last three times it was an overheat alarm. I then watched the live data as the temperature climbed right up to 80C and it went into limp home mode and threw another overheat alarm. All while just idling. It took about 15 minutes to overheat at idle. The live data shows the actual reading from the temp sensor. It started off about 35C and slowly climbed to 80C which is pretty much what I would expect. Because my df15a is a manual start the thing has to run 15 seconds or so before the software starts picking up the data. It pulls the power from the reader off of the outboard so it doesn't boot up until the engine is running unless you have a 12v source attached to it. I had a setting wrong in the computer so it had run for about 30 seconds or so then I shut it down fixed the computer side. When I started it up the temp was 35C, but the water temp was 31C. A four degree temp rise for 30 seconds of running and then sitting for about 5 minutes seems reasonable.

[Simi 60]

We had an overheat on the DT30 suzi a couple of weeks back
No computers, no alarms on these ones.
Revs dropped off, I thought it was the extension handle losing grip but when I realised it wasn't shut it down.

Then there was steam coming out of the cowling, took it off to more steam and smell.
Not much I could do so started her up to get water flow, at least it wasn't seized.
Big puff of steam out the exhaust then ran as normal so figured head gasket.

Ran her slowly the 5 miles or so back to the boat and there was visible head gasket degradation.

Took off leg, impellor was fine, I had replaced it 6 mths ago but there was a bit of oyster shell in the inlet to the impeller housing obviously restricting flow.

Back together and she runs fine and has full power, just dont run her full tits or for long I'm guessing.

Should have a new head gasket waiting for me at the post office today so a few miles in and back and hopefully it'll be an easy fix.

[Captain Bill]

Originally Posted by Simi 60

We had an overheat on the DT30 suzi a couple of weeks back
No computers, no alarms on these ones.
Revs dropped off, I thought it was the extension handle losing grip but when I realised it wasn't shut it down.

Then there was steam coming out of the cowling, took it off to more steam and smell.
Not much I could do so started her up to get water flow, at least it wasn't seized.
Big puff of steam out the exhaust then ran as normal so figured head gasket.

Ran her slowly the 5 miles or so back to the boat and there was visible head gasket degradation.

Took off leg, impellor was fine, I had replaced it 6 mths ago but there was a bit of oyster shell in the inlet to the impeller housing obviously restricting flow.

Back together and she runs fine and has full power, just dont run her full tits or for long I'm guessing.

Should have a new head gasket waiting for me at the post office today so a few miles in and back and hopefully it'll be an easy fix.

I had thought about a possible head gasket issue. It may come to that but I'm hoping I can Identify a simpler problem. It may still come down to that though.

[CaptNemoO2]

Originally Posted by Captain Bill

Sorry to have to come back to this thread. I am still having trouble with my DF15A overheating. Last fall I flushed it in a barrel for 3 hours with diluted phosphoric acid recirculating. The water in the barrel got pretty hot but the overheat warning never got triggered. I flushed it for an hour with clean fresh water afterwards. It's about a 30 minute run from the boat ramp to my boat. I put it back in the water and ran back to my boat with no problem. I put it on the davitsand flushed it with fresh water while hanging on the davits. About a month later I dropped it in the water and it overheated before I got out of the idle speed only area of my canal system. I figured the high temp. of the water might have eaten the water pump so I pulled that. No vanes missing and it still seemed flexible, but since I already had the kit I changed it anyway. It still overheats. I bought a Suzuki diagnostic software kit which said it had the service manual for the 2014 EFI version of the DF15a. They lied. It only had the manual for the carbureted version. It confirmed overheating and when I watched the temperature as the engine warmed up it looked like I would expect with the temperature rising over time until it hit 80C and the overheat warning triggered, so it doesn't seem to be a bad temp sensor. I pulled the thermostat today and heated it in a pan of water and it started opening at 136Fand was fully open by about 142 which is in spec. I pulled the zinc cover off as well and flushed he head. The thermostat opening had significant salt deposits while the zinc opening was very clean. I put the hose in the flush fitting and water flowed freely out of the zinc hole and out of the bypass(?) hole in the thermostat housing, but no water at all came out of the thermostat hole. Looking at the waterflow diagram in the manual I have part of the flow that goes through the heat goes out the pee hole and part goes to the thermostat. The engine has always had plenty of water coming out of the pee hole. I assume (I know) that the water that is coming out of the hole into the thermostat housing is the water that is supposed to go from the head to the thermostat housing in the diagram. Water is also supposed to go through the oil pan to the thermostat and then back through the oil pan and out the exhaust. Unfortunately something in the cooling system must have changed between 2013 and 2014 because the 2013 diagram describes a cooling water hose after the thermostat but there doesn't seem to be any such item on my engine. I am assuming that no water or very little gets to the back side of the thermostat and I must have a clog in the system between the water pump and the thermostat but after the flow is split off for the thermostat channel. Does anyone have a diagram of the water flow in a 2014 or newer DF15a or the 9.9 or 20 hp versions as they use the same power heads. It's pretty clear to me that none of the things done by me or professional mechanics has done much to the clog as it clogs in relatively short order.

If you think there's salt build up past the thermostat, can you remove the thermostat, close the housing back up and do your flush again? It probably wouldn't get hot enough to dissolve the salt with just straight water, but adding in some chemical it might.

[ranger58sb]

When we had the problem, our local dealer tried flushing with Salt Away, for hours I think. Didn't work. They disassembled and actually chipped out the salt build up from around the (hmmm... around the outside of the cylinder walls, I think...). Sounded like they used an ice pick.

-Chris

[Captain Bill]

I found and bought the correct version of the service manual online last night. I Found that the head and block design are completely different than the 2013 model. The pee hole water on this model only goes through the fuel cooler and then directly overboard. It never gets to the block or head so it is not an indication that water is actually getting to the power head, only that the water pump is working. I also found a Suzuki outboard forum where there is an ongoing thread about this kind of issue. At this point it is clear to me that there should be cooling water on the thermostat but when I put a hose in the flush fitting no water comes out of the thermostat hole. It's pretty clear that I have a severe clog in that channel. I guess I'm going to have to pull the power head and manually unclog it since chemical treatment is not doing the job.