Salt Build up in Suzuki Powerheads

[a64pilot]

So limp home mode is a reduction in RPM, but the motor runs normally?
Some motors in response to an overheat like Cadillac’s Northstar and the Duramax Diesel will shut down cylinders and rotate these shut down cylinders, Does the little Suzuki do that, or just reduce RPM?
I wonder why only some motors seem to have this clogging problem? And it seems to correspond with periods of not being used?

I was in Long Island, specifically Salt Pond, Salt Pond’s salinity is so high that watermakers perform poorly there with low output and high TDS in the product water.
Then due to the virus my motor sat for at least a month on the rail. So I was wondering if my missing at idle was fuel or an overheat.

I’m not aware of any outboard that the pee line is an indication of anything but the pump running, I think they all come off the pump before the power head.

[Captain Bill]

Originally Posted by a64pilot

So limp home mode is a reduction in RPM, but the motor runs normally?
Some motors in response to an overheat like Cadillac’s Northstar and the Duramax Diesel will shut down cylinders and rotate these shut down cylinders, Does the little Suzuki do that, or just reduce RPM?
I wonder why only some motors seem to have this clogging problem? And it seems to correspond with periods of not being used?

I was in Long Island, specifically Salt Pond, Salt Pond’s salinity is so high that watermakers perform poorly there with low output and high TDS in the product water.
Then due to the virus my motor sat for at least a month on the rail. So I was wondering if my missing at idle was fuel or an overheat.

I’m not aware of any outboard that the pee line is an indication of anything but the pump running, I think they all come off the pump before the power head.

According to the service manual for the pre-2104 the water first goes through the head before the Pilot water hole. I have attached a copy of that page for educational purposes.

[Captain Bill]

Originally Posted by 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.

I don't often quote myself but I thought I would give an update on my cooling problem and obviously clogged water passages in my 2014 Suzuki DF15a. After several attempts at chemical treatment I finally gave up and took the head off. It was worse than I ever imagined. The head was relatively clear, but the block was almost solid. The water jackets surrounding the cylinders were filled with two kinds of deposits. The first was what looked like moist crystallized salt and was relatively easily removed. The second was what could only be described as limestone rock. It resembled the mother of pearl on the inside of an oyster shell and just as hard. I had to actually use a twist drill to drill into it so I could remove it. Every opening was severely clogged. The opening from the block water jacket to the thermostat housing is approximately 1/4 inch wide and over an inch long. It was reduced to an opening about 1/8x1/4 inch. It didn't matter because there was no water getting to it anyway. The opening from the water plenum, where water from the lower unit is fed to the block and head, was so blocked that I could not even find it. Eventually poking around with a sharp metal probe I found a slightly softer spot in the wall. I again had to use a twist drill to break out the deposit. Eventually between using physical means and chemical means I managed to reach the metal walls. I did have to clean a few passages in the head, but they were not nearly as bad as he block. In any case, the unit is now cleaned out and running well again.



My major concern is that the owners manual warns about using this motor in salt water and requires flushing after every use in salt water. This is not practical in a cruising boat. Even if I could flush it after every use I would have to use the hose attachment which cannot be used to with the motor running. I flushed using this method a few times a year when at a dock, but because the engine never warms up, little or no water goes through the engine block which is regulated by the thermostat. The water going through the head bypasses the thermostat and can be flushed with the hose attachment. I suspect that this explains why the head was relatively clear and the block, for lack of a better term, was blocked. The thermostat for these engines does not even have a bleed hole which I have found to be common on most thermostats I have worked with. I have tried numerous "ear muff" type flush attachments but have yet to find one that will conform to the shape of the lower unit and get water to the water pump so I can flush the engine. The only effective way I have found to flush the engine while it's running is in a barrel.



My conclusion is that this engine is probably not an appropriate choice for a cruising boat. While I love the easy starting and running associated with the fuel injection, the cooling system issues are way too significant. If one peruses the forum and Suzuki engine forums the cooling issue is just way too common. If you are a part time cruiser where you can barrel flush the engine on a fairly regular basis then it will probably be ok, but not for a full time cruiser with limited ability to flush it properly. You really have to get the thermostat open to flush the block and the thermostat cover is not easy enough to remove to do it on a daily basis, so you have to run the engine.

[Boatguy30]

In many peoples experience, if you can't flush the engine every time for an extended period. You're better off never flushing. Possibly the Suzuki does not drain down properly when shut off?

That's very well proven on various Yamahas Tohatsu and OMC motors. Give it a try

[GRIT]

Thank you Captain Bill. Information like this could be very handy for those of us using Suzuki outboards.

Cheers.
Paul.

[ranger58sb]

Originally Posted by Captain Bill

I don't often quote myself but I thought I would give an update on my cooling problem and obviously clogged water passages in my 2014 Suzuki DF15a. After several attempts at chemical treatment I finally gave up and took the head off. It was worse than I ever imagined. The head was relatively clear, but the block was almost solid. The water jackets surrounding the cylinders were filled with two kinds of deposits. The first was what looked like moist crystallized salt and was relatively easily removed. The second was what could only be described as limestone rock. It resembled the mother of pearl on the inside of an oyster shell and just as hard. I had to actually use a twist drill to drill into it so I could remove it. Every opening was severely clogged. The opening from the block water jacket to the thermostat housing is approximately 1/4 inch wide and over an inch long. It was reduced to an opening about 1/8x1/4 inch. It didn't matter because there was no water getting to it anyway. The opening from the water plenum, where water from the lower unit is fed to the block and head, was so blocked that I could not even find it. Eventually poking around with a sharp metal probe I found a slightly softer spot in the wall. I again had to use a twist drill to break out the deposit. Eventually between using physical means and chemical means I managed to reach the metal walls. I did have to clean a few passages in the head, but they were not nearly as bad as he block. In any case, the unit is now cleaned out and running well again.

That description is similar to what our dealer found with ours. And what they had to do to clean it all out...

We got ours in 2014, too...

We had a muff that worked well enough; nothing special, no difficult or extensive shopping to find it, just grabbed the first one off the shelf -- probably at West Marine, but that's guessing. I just hadn't used it often enough (I guess).

-Chris

[Captain Bill]

Well I'm back and it's overheating again. I've been doing a lot of work on the big boat and only had it out about 5 times since I reported it working well again back at the end of Sept. I've been using the fresh water flush port but since it doesn't open the thermostat it had not been getting flushed properly. I opened the thermostat housing and there were crystalized salt deposits on the thermostat. I cleaned them off, checked the thermostat operation on a pot of hot water, and reinstalled. While I had it out I attached a hose to the flush port and made sure I had good water flow through the thermostat hole. I'm thinking of drilling a 1/16th hole in the thermostat to let the air out and some water through when doing a flush. Does anyone see a problem with doing that. Most other thermostats I have seen have a small air bleed hole in them. If that doesn't work, I think the next step is a new motor.

[Doubl0h7]

Any update Cap’n Bill? I just dragged my DF20a home after spending $1600 with the Suzuki dealer in Naples (should have verified the overheat was fixed before I fixed the prop shaft trama) How bad is the head removal job? Should I port and polish the water passages in the block? Any results with the hole drilled in the thermostat? Should I just cut my losses and buy a Tohatsu?

[Captain Bill]

Originally Posted by Doubl0h7

Any update Cap’n Bill? I just dragged my DF20a home after spending $1600 with the Suzuki dealer in Naples (should have verified the overheat was fixed before I fixed the prop shaft trama) How bad is the head removal job? Should I port and polish the water passages in the block? Any results with the hole drilled in the thermostat? Should I just cut my losses and buy a Tohatsu?

The short story is that I bought a Tohatsu. The long story is that the head cleaning job lasted for one 3 week cruise despite me running it in a barrel for an hour when I got back. I didn't use it for a month and the next time I did it overheated in about 10 minutes. Took the thermostat out and the passages were full of semi crystalized something and the head was clogged again. The hole in the thermostat obviously didn't help. After an hour in the barrel I would have thought it was well flushed. I don't know what the corrosion is but it seems that once it starts it will occur any time you let the engine sit unused for a few weeks. The Tohatsu works great by the way. Mine is a manual start and usually takes three pulls but sometimes only two. I guess well see if it does any better than the Suzuki after a couple of years.

[rslifkin]

I'd think you could run an outboard in a barrel full of diluted Barnacle Buster to dissolve salt and junk out of the water passages. The only big caveat is this: if the water passages are zinc coated to prevent corrosion, it will likely eat away the zinc coating and lead to corrosion-induced failures at some point down the road.

[Doubl0h7]

Cap’n Bill I hate to hear that because I love the motor otherwise. How many hour job is pulling the head? Any special tools?

I’m thinking I’ll clean it out and sell it up here to someone to use on fresh water where it should be no problem.

Originally Posted by Captain Bill

The short story is that I bought a Tohatsu. The long story is that the head cleaning job lasted for one 3 week cruise despite me running it in a barrel for an hour when I got back. I didn't use it for a month and the next time I did it overheated in about 10 minutes. Took the thermostat out and the passages were full of semi crystalized something and the head was clogged again. The hole in the thermostat obviously didn't help. After an hour in the barrel I would have thought it was well flushed. I don't know what the corrosion is but it seems that once it starts it will occur any time you let the engine sit unused for a few weeks. The Tohatsu works great by the way. Mine is a manual start and usually takes three pulls but sometimes only two. I guess well see if it does any better than the Suzuki after a couple of years.

[Doubl0h7]

Sadly that’s what the Suzuki dealer did for almost a week. They got it better, no longer alarms at wake speed, high temp alarm waits to go off until about a thousand yards or so on plane at WOT.

I’m agreeing with Cap’n Bill that the small Suzuki’s have a design flaw. Really small passages for cooling in the block along with much higher temperatures inherent with a fuel injected engine apparently cause hard mineral deposits in salt water.

Probably fine in fresh water but they are a time bomb in salt.

Originally Posted by rslifkin

I'd think you could run an outboard in a barrel full of diluted Barnacle Buster to dissolve salt and junk out of the water passages. The only big caveat is this: if the water passages are zinc coated to prevent corrosion, it will likely eat away the zinc coating and lead to corrosion-induced failures at some point down the road.

[Captain Bill]

Originally Posted by Doubl0h7

Cap’n Bill I hate to hear that because I love the motor otherwise. How many hour job is pulling the head? Any special tools?

I’m thinking I’ll clean it out and sell it up here to someone to use on fresh water where it should be no problem.

Pulling the head was very straight forward. Just your basic metric sockets and wrenches along with a screw driver and pliers for the hose clamps. The big problem was getting the "stuff" out of the cooling passages in the block. It was literally as hard as a rock. I actually had to drill it to break it up and get it out. The most difficult passage is the one coming out of the cooling water plenum at the base of the block. There are two passages exiting that plenum. It took me quite a while to even find the one to the block. The one that goes to the head is larger and more obvious(hint: the block port is on the opposite side of the plenum from the head port). I had to probe around with a sharp pick until I found a slightly softer spot in the aluminum. Note that the plenum had a lot of corrosion in it too, just not solid rock. After chipping a bunch of "Stuff" out of that opening I found that about a cm in it turned 90 degrees. Getting the rest of that tube open was a really a problem. I dripped phosphoric acid into the hole let it sit a while and then flushed it with fresh water and then repeated. A little "stuff" would come out with each flush. It took about 8 hours before I got it open and I could get water into the block through that port. Also I used lots of WD40 during this process to keep water away from the cylinders and pistons. The other problem area is the port from the block to the thermostat housing. It's actually about a inch or so long and is shaped like a slit. I was almost fooled thinking that when i saw a 1/4 inch hole open in the corrosion that I had achieved success since the hole was bigger than the intake port to the block. Only when I accidentally got the rest of the hole open when picking a the "last" piece of crystalized corrosion did I realize there was such a big opening there. The head had some corrosion, but the passages there were much bigger and not completely clogged so were pretty easy to clean.



It only took me about an hour and a half to pull the power head and the same to reinstall it. Tearing down the power head was probably a couple of hours, mostly because I was going slowly. Reassembly requires a torque wrench and new head bolts and of course a new head gasket.



I was thinking of selling mine to someone for fresh water use as well, but I'll have to clean it out again first and I'm not sure that it's worth it. I'm also not sure that after whatever coating they put in the passages is gone if it will ever be "right" again.

[malbert73]

Glad to hear I “guessed” right when I bought my Tohatsu 15 EFI manual start 4-5 years ago. As I recall it was the only EFI in 15hp at the time. Still flawless. The EFI without a battery I believe leads it rarely to start before 2-3 pulls, but that’s a small trade off to avoid carb issues etc

[Doubl0h7]

Head is off and it was the block passages just behind the thermostat that was packed full.

It was fairly soft but that’s probably because of the Suzuki dealers hours of running barnacle buster and salt away.

I had the shop manual but since I used to make my living doing recalls as a VW/Audi/Porsche mechanic I left the power head on and didn’t pull the flywheel as described in the manual. Just don’t forget to put a little silicon at the head/oil pan/block junction.

Head comes off just fine skipping all those steps, just make sure you paint mark your flywheel and cam so you keep it in time. It’s a interference motor and really, really bad things happen if you get it off a cog or three.

I was tempted to copper coat and reuse the head gasket as it looked pretty ok but spent the $70 and ordered it in.

I’m hoping for a better outcome than Cap’n Bill had and I get a few more years out of it. Marc Cole helped me out with advice. His mechanic pulled out a ziplock full of crap and the motor is still going 3 years later.

Originally Posted by Captain Bill

Pulling the head was very straight forward. Just your basic metric sockets and wrenches along with a screw driver and pliers for the hose clamps. The big problem was getting the "stuff" out of the cooling passages in the block. It was literally as hard as a rock. I actually had to drill it to break it up and get it out. The most difficult passage is the one coming out of the cooling water plenum at the base of the block. There are two passages exiting that plenum. It took me quite a while to even find the one to the block. The one that goes to the head is larger and more obvious(hint: the block port is on the opposite side of the plenum from the head port). I had to probe around with a sharp pick until I found a slightly softer spot in the aluminum. Note that the plenum had a lot of corrosion in it too, just not solid rock. After chipping a bunch of "Stuff" out of that opening I found that about a cm in it turned 90 degrees. Getting the rest of that tube open was a really a problem. I dripped phosphoric acid into the hole let it sit a while and then flushed it with fresh water and then repeated. A little "stuff" would come out with each flush. It took about 8 hours before I got it open and I could get water into the block through that port. Also I used lots of WD40 during this process to keep water away from the cylinders and pistons. The other problem area is the port from the block to the thermostat housing. It's actually about a inch or so long and is shaped like a slit. I was almost fooled thinking that when i saw a 1/4 inch hole open in the corrosion that I had achieved success since the hole was bigger than the intake port to the block. Only when I accidentally got the rest of the hole open when picking a the "last" piece of crystalized corrosion did I realize there was such a big opening there. The head had some corrosion, but the passages there were much bigger and not completely clogged so were pretty easy to clean.



It only took me about an hour and a half to pull the power head and the same to reinstall it. Tearing down the power head was probably a couple of hours, mostly because I was going slowly. Reassembly requires a torque wrench and new head bolts and of course a new head gasket.



I was thinking of selling mine to someone for fresh water use as well, but I'll have to clean it out again first and I'm not sure that it's worth it. I'm also not sure that after whatever coating they put in the passages is gone if it will ever be "right" again.