water circulation 9.9 block

[MIDORI]

I have read most of the past posts on this topic.

I am checking the water flow prior to heading south.

1998 9.9 Yamaha.

The top nipple on the port side has NO water discharge.

I removed the nipple and scraped a good teaspoon of crud from the block, it looked more like sand than salt. I have flushed the system several times with Salt Away.

I removed the valve cover, the water channel on the port side has what appears to be factory stamped plugs in both the top and bottom nipple water ports.

I have read the links from Colin Swithenbank and Roger Ford who have discussed the water flow in detail but there was no mention of factory blocked passages.

Has anyone seen a similar problem?

Does anyone have a contact at Yamaha that could verify the factory closed passages?

Brian Munroe
MIDORI
32032

[next exit]

Try removing the thermostat and see if you have watrer flow.

[Allezcat]

Brian,

I recently had a similar problem (no waterflow). I traced it to a complete salt block under the water pump plate (which is the water intake cavity). This is the 4th time I have had this exact same problem in the same location. I think this is a design deficiency of this engine.
If you run the engine for any length of time in this condition , the water pump will fail as it is running dry which creates heat. The rubber fingers then crack and break off.
It seems to happen only when the engine has not been run for a few weeks after having been used in saltwater. If the engine is used every few days there seems to be no problem, even if it is not fresh water flushed.
Of course, the fix involves removing the engine, lower unit, and water pump, not my favorite job!

Chet
Allezcat 36010

PS - I first tried flushing out the block using "ears" on the lower unit and pressure fresh water. No luck!

[MIDORI]

Thanks to Don and Chet.

I should be more specific. I removed the thermostat, cleaned out all the junk and filled the block with a "Salt Away" solution, several times. I think this product works.

I have great water flow. After reading the historic exchanges between Colin Swithenbank and Roger Ford on the topic," Yamaha thermostat removal", I used pieces of aquarium hose to check the water flow at each of the accessable water ports. Flow at the P hole does not mean water flow, very true.

I have flow at the thermostat and at the bottom port nipple (gushing). I assume water flow under the engine. It is the top port nipple that has no flow at all.

At this point I cannot understand a blockage at the top nipple, I have removed the nipple its self ( carefully) and dug out crud but still no flow.

MIDORI
32032

[Cat Tales]

Brian,

I have not had the pleasure of tackling this problem yet, but I wonder if trying to clear the water line with a wire "snake" (like a coat hanger, but more flexible), would work to physically dislodge any blockage.

Chris

[next exit]

To best of my knowledge, I've only had water come from one nipple

[charlie phillips]

Brian,

I had the identical situation. Like you, I read through all the previous postings and articles. Here is what I found.

I first removed the brass nipple and started poking around. The hole was filled with calcium carbonate. (the sand like substance you found). I was able to get some of it out, but not enough to clear the passage.

Next, I removed the valve cover and found the same metal plugs just above (motor tilted up at this point) the nipples. The plug above the blocked nipple was skewed. I started cleaning the calcium carbonate around it and it came loose. With the plug gone, I was able to clean the entire passage to a depth of 3 5/8 inches (down to about the next gasket). The blockage seemed to stop at a depth of 2 1/2 inches, but I'm sure this will vary. I used several tools, including a drill to get out the hardened calcium carbonate. Some vinegar helped to dissolve the CC.

On engines like ours with the valve cover water passage blocked by the plugs, there is a hole in the valve cover over the water passage. This means that without both plugs in place, cooling water will escape inside the engine cowling. I didn't want to plug the valve cover hole, as any leakage in the valve cover gasket would allow salt water into the oil reservoir. I wonder if Yamaha blocked the valve cover passage for that reason. Does anybody know?

Instead, I used a rubber stopper to replace the removed plug. The hole is tapered and the stopper fits well. It is critical to cut it to just the right length so the valve cover puts a little pressure on it to create a good seal. I tried to find a high temperature stopper, but couldn't get one locally. From what I was able to find out, the regular stopper I got at the hardware store is good to about 250 degrees F.

I have about 10 hours on the engine since the fix and all is well. I plan to remove the valve cover and check the stopper condition before next season.

I didn't plan to do this, but when the plug came loose, I was committed.

My next step is to install a built in flushing system. I haven't decided on a design yet - there are several approaches in use. At the moment, our boat is in the Columbia River in Portland, so the pressure is off on that project, but we plan to sail up to Puget Sound next summer.

You mentioned using Salt-Away. From what I hear, Salt-Away is fine for it's intended use, but it is not designed to dissolve calcium carbonate (which is not salt). For that, you need some type of mild acid. Vinegar helps and may be fine for regular maintenance. Something stronger, such as muriatic acid (hydrochloric acid) may be needed for tough cases. The problem is knowing how strong is too strong as far as damaging the engine. There has been some discussion of this but no clear conclusions that I can find.

From what I have read, overheating due to clogged cooling passages is the leading cause of death for salt water 9.9's. I am looking into adding temp gauges with alarms. Has anyone done this?

Hope this helps.

Charlie Phillips
Portland, OR
PDQ32 -46

P.S. Congrats on the new boat. We love ours.

[wbrou]

I also had blocked cooling passages through the head on my 1998 Yamaha 9.9's. To remove the blockage, I removed the valve cover, and drilled out the cooling passage plugs (in my case they were both tightly seated), using first a small drillbit directly in the center of the plug, and then a 1/4 in. bit. The 1/4 in. bit was then also used to drill out the very hard salt deposits in both passages (my attempts to clear with a stainless wire were unsuccessful), and the external brass hose nipples were removed to clean that section out with an appropriate drillbit (by hand). I next used a 5/16 in. tap to thread the cooling passage holes, and sealed these with a 5/16 in. stainless bolt (must have a small Allen wrench head to fit) with neoprene gasket and gasket cement for each. This has been used one season without any leaking, although one passage clogged again. Cleaning was now much easier with the removable bolts sealing the cooling passage plugs.

Wayne
#36042

[swithen]

With Cadenza out of the water, I cleaned the calcium carbonate from ALL the water passages by immersing the lower unit (prop. removed) in a 40 gal plastic (trash) container filled with vinegar, then running the engine for 15- 20 mins. until the vinegar became warm. This was followed by thorough flushing with fresh water. Since this treatment, the engines have taken us on two six month trips to the Rio Dulce and to the Bahamas and no deleterious effects from the treatment have shown up.
Note that this treatment should not be necessary until the engines have at least 1,000 hours on the clock.

Colin Swithenbank
Cadenza 36051

[Cat Tales]

40 gallons...That's a lot of vinegar (though it was probably only half full). Did you dilute the mixture at all? Also, while traveling, did you regularly (meaning everytime you used the outboards) flush with fresh water?

It was stated in an earlier post under this subject that calcium carbonate is not salt, hence Salt-AWay won't work. If it's not salt, where/how does the calcium carbonate originate from?

Chris

[Page 83]

In seawater,Calcium Carbonate ( a common ingredient in antacids,) comes from shellfish, who must have a high rate of heartburn from eating all that yuck on the bottom. [giggle]

[swithen]

Chris

In response to your questions (probably more than you wanted to know!):

1. We used the vinegar directly out of the bottles from Costco without dilution. I did some preliminary experiments with calcium carbonate sand (oolitic limestone/Aragonite) I brought back from the beach on South Warderick and found diluting the vinegar slowed down the rate of solution propotional to the amount of water added.
Note that sand in the U.S. north of Florida is chemically different being composed of silica or silicates, is less coherent, and accepts anchors more easily than the “sticky” carbonate sand in the Bahamas.

2. We never flush the engines with water during normal use considering it to be neither practical or useful. The calcium carbonate is precipitated on the inside of the cooling system during engine use and once precipitated will not dissolve in water (or Salt-away). The calcium carbonate precipitates because it has an inverse Solubility Coefficient, i.e. it is less soluble in warm water than cold: its solubility in sea water is 10 mg/liter @ 20degC and 100 mg/liter @ 0degC.

3. Where does the calcium carbonate come from?
Sea water is already saturated with calcium carbonate but the concentration of the component ions is quite different: calcium 0.04% and carbonate ca. 0.000000004%. Calcium ions historically come from rivers and the sea bed over geological time. Carbonate arises from carbon dioxide in the air but the process is complex. Carbon dioxide dissolves initially to form carbonic acid making sea water slightly acidic, and the dramatic increases in carbon dioxide concentration in the atmosphere since the start of the Industrial Revolution have made the seas more acidic (I noted one estimate that 50% of all carbon dioxide produced dissolves in the sea). Natural buffering capacity of the seas convert the carbonic acid instantaneously to bicarbonate and carbonate depending on the pH of the local sea water.
Note that calcium carbonate is more soluble in sea water (6 x 10exp-7) than in fresh water (5 x 10exp-9 both at 20degC). These figures are both very low and it would be accurate to say that calcium carbonate is “virtually insoluble” in water.
It is interesting to note that nature uses calcium carbonate for shell fish, and that the evaporative process for salt (sodium chloride) from sea water requires preliminary ponds to keep the calcium carbonate out of the salt . The geological formation of the Bahamas is dependent on the same process. Sea water warms as it flows over the shallow islands, precipitating oolitic calcium carbonate. This process in conjunction with surrounding coral reef have kept the land surfaces at sea level even as the islands have sunk into the sea. Borings have shown that the carbonate from as deep as 5000 feet was all at the surface when originally formed. You may be interested in a monograph by Neil E. Sealey: Bahamian Landscapes - An Introduction to the physical geography of the Bahamas, which describes this process. I note that Amazon lists three new and used copies from $7.99 and bn.com lists one used.

[Allezcat]

Colin
Thanks for that excellent dissertation on carbonates.
What would happen to the deposits in the engine and the aluminum if one was to use muriatic acid to clean it?
I recently used muriatic to remove the remains of barnacles stuck to the bottom of the hulls. It worked great and dissolved the material into a foaming substance which washed away.
Chet
Allezcat 36010

[SecondWind]

Please do NOT use muriatic acid (also known as hydrochoric acid) in your engines. You will rapidly convert the aluminum parts into aluminum choride. You will create an anode-cathode reaction (i.e. a battery) which could harm other engine components, including water pump bearings. You also will generate chlorine gas in the process, which is deadly to breathe and is environmentally hazardous. You could dilute it, but in the long run Acetic Acid (vinegar) is far safer for both you, the engine, and the environment.

[Cat Tales]

Colin, you can never learn too much. Thanks for the in-depth response!

We have a fresh water line that connects both outboards so that we can flush the engines with a flip of two valves. With the new 9.9's I've gotten into the habit of flushing immediately after each use, even if it's only for a 12 hour stay. I now know this will prevent salt build-up, but not calcium carbonate. Assuming constant useage in the Bahamas, where calcium carbonate is probably more coherent, can anyone recommed how often vinegar should be used. Is every 500 hours too long to wait, or should it be used only when the cooling passages are noticeable blocked?

Thanks
Chris