Water in oil AR230HO MR1 engine

[MaxHO]

Hi fellow boaters, I own a 2005 AR230HO from new. I live in the Netherlands and using the boat very sparingly. I do all maintenance and repairs myself. During my ownership I have pulled the engines in totaly already 5 times. Within 2 hours I have the engine out. During the years many problems have been solved. All of them as described here in the forum. Last year I found water in my starboard engine. The oil turned into a light brown milky substance. It is definitely water and oil and not fuel dillution. I have the CDI with sticky injector a year before, so I could easily indentify. So I run trough all the items to check. Water is not entering the combustion chamber(s), compression test was fine. O-Ring at the waterpipe from cylinderhead is fine. All exhaust gaskets are fine, also the seal rings between the inner & outer muffler pipe. The oil tank/ oil cooler assembly is perfect. The Cylinder head gasket didn't show any sign of leak and defect. The cylinder block (upper crankcase) water jackets are fine and the oil gallery. I suspect the cylinder head must be cracked, do you know wether this happened before? Is it a known problem? Like to hear from you. Thank you in advance.

 

[Cobra Jet Steering LLC]

check the exhaust manifold for corrosion around the water jackets very common for those engines the yellow arrow shows where you look for
corrosion

 

[MaxHO]

Dear Scott,
Thanks for coming back to me so quickly. I use the boat only in sweet water, never have been in salt water. The exhaust manifold cooling passages are very clean and absolute free from contamination/ corrosion. And as I mention there is no water entering into the combustion chambers.
BTW since 2006 or 2007 I have Cobra Jet Steering on the boat! Thanks & Regards Max.

 

[Cobra Jet Steering LLC]

Dear Scott,
Thanks for coming back to me so quickly. I use the boat only in sweet water, never have been in salt water. The exhaust manifold cooling passages are very clean and absolute free from contamination/ corrosion. And as I mention there is no water entering into the combustion chambers.
BTW since 2006 or 2007 I have Cobra Jet Steering on the boat! Thanks & Regards Max.

OK those were very popular steering systems, now my steering is so different and so effective plus there are many upgrades as well but I see a lot of people who still use that style, glad you are enjoying them. now I wonder what is causing water to get in your oil. I have seen overheating cause a head to warp. I have even heard of the muffler having broken baffles that caused issues with excessive back pressure. The most common issue is the exhaust manifold corrosion I showed you. Is there any water spraying inside the hull that could be hitting the air filter? Maybe a cooling hose or pisser hose check how the air filter element looks. A cracked head would be obvious with a leak down test. However water in the combustion chamber will usually make the plug tip silver as it removes aluminum from the cylinder walls and deposits it on the spark plug also if you look in the plug holes and rotate the engine you can view the top of the pistons, any of them getting water in the cylinder will have NO carbon on top of the piston at all . It will look very clean and shiny.

 

[Beachbummer]

Head gasket could be it. I don't know how to do it, but you need a leak down test to check head gasket and valve health.

 

[MaxHO]

Hello fellow Jetboaters, I own my AR230HO since 2005. I live in Europe where the Yamaha Jetboats are never sold. I'am a technical guy and do all the repair myself. During the years of happy ownership I have faced the common issues. Big issues were water leakage by cracked crankcases (on both engines) failing ECM (one unit). My present challenge is that I found water in my engine oil. There are no water traces inside the cylinder(s) and not hard starting. Since I do all the repairs myself and in meanwhile well experienced, so II did the following checkes. Checked manifold on pinch by corrosion, (although there is no water entering the cylinders), I didn't found any pinch. (Boat only used in sweet water), O-ring of upper waterpipe at valve cover/ cyl. head location was fine, no leakage. I took out the engine for deeper inspection. Removed the head, the headgasket was fine, no trace of imperfection. Next I completely dismanteld the engine to look further inside the upper crankcase half. I have repaired the well known (exhaust side) crankcase crack some 6 years ago. It has worked fine during the years. At the inside of the crankcases I didn't find any crack or whatever. But the repaired hairline crack (on the outside the crankcase) did grow and have reached one of the cylinder studbolts. Cooling water must seep through the internal crack to the studbolt. From there the water its free to raise along the studbolt to the cylinder head area. There at the cylinder head it will contact and mix with the engine oil. A long story but I'am glad I found it. I will try to make the studbolt area watertight.
Thank you all for supporting me in my diagnose search!

Regards Max

 

[Scottintexas]

wow ! great job tracking this down,

I have to wonder two engines and both with cracked cases ??? I don't think we've ever seen both engines have the problem, I wonder if there's any coloration between them or just bad luck,

I remember the several member with non-ho engines have a history of having a the block crack in a certain area,

 

[kjr6306]

Interesting. My issue was a cracked head. The only way I found it was by pressurizing the cylinder head. I will watch the thread to see if the crack at the stud bolt fixes your issue.

 

[MaxHO]

Hi kjr thanks for reaction and comment. I have completed the engine built, but it is still on the bench. Based on your experience I will pressurize the engine first, with the valve cover off. In order to eliminate the possibility of a cracked head. Do you have any pics of the cracked head in order to simplify my search for the (possible) problem area?

Kind Regards!

 

[kjr6306]

https://jetboaters.net/threads/2005-sx230ho-milky-oil.38287/page-2

This thread pretty much covers what I went through. Post #27 shows where the head was cracked. Isolated the head and rigged up a way to block off all of the water jackets and ways for water to get in and out of the head. Then pressurized the head and found air coming out between 2 valves. Confirmed with a little soapy water to produce the bubbles in the picture. If I recall correctly, the area where you found the crack has nonpressurized water so the likelihood that the water is flowing upward against gravity is slim. I may be wrong bout this as it's been a while since I last looked at this issue. Unfortunately, you already have the head/engine reassembled so it would be more work to remove the head again to check it. Although, I got pretty good at taking off the head. You can actually take it off with the engine installed but it's more of a PIA. Keep us posted and let me know if I can help.

 

[MaxHO]

https://jetboaters.net/threads/2005-sx230ho-milky-oil.38287/page-2

This thread pretty much covers what I went through. Post #27 shows where the head was cracked. Isolated the head and rigged up a way to block off all of the water jackets and ways for water to get in and out of the head. Then pressurized the head and found air coming out between 2 valves. Confirmed with a little soapy water to produce the bubbles in the picture. If I recall correctly, the area where you found the crack has nonpressurized water so the likelihood that the water is flowing upward against gravity is slim. I may be wrong bout this as it's been a while since I last looked at this issue. Unfortunately, you already have the head/engine reassembled so it would be more work to remove the head again to check it. Although, I got pretty good at taking off the head. You can actually take it off with the engine installed but it's more of a PIA. Keep us posted and let me know if I can help.

Thanks for the pics, they certainly makes my job much easier. Good idea's how to block off the waterpassages. I didn't installed the head yet, my last picture was the engine removal from the boat. Your experience and pics, convinced me to check the head thoroughly before installation and not making a conclusion too quick.
I experienced with all "common" problems with my AR230HO, such as cracked crankcases, CDI failure (fuel dumping), broken off spark plug, failing starter relay, leaking exhaust manifold pipe ring gasket and all sort of things.
Do you know if a cracked head is a 'common' problem? Here in Holland I'am the only AR230 Jetboat owner, since they were never exported to Europe.

Regards Max

 

[kjr6306]

I think there have been a few people that have documented cracked heads. If anything the exercise of sealing the head will make you an expert on where the oil should be and where the water should be in the engine cooling system. There is a really good YouTube video that explains the entire cooling system of the MR-1. It's not entirely correct but it covers most of the basics. Let me know if you have any question on how I sealed up the head to pressurize it.

 

[MaxHO]

The repair continued, the head has been pressurized and no leak found. With a solid straight steel plate, a thick soft rubber mat and four large clamps the job has been done. There was a small leakage due the center intake valves, which are sticking out a few millimeters from the head surface and couldn't compensated by the rubber mat. So I removed the related intake valves, plugged the exhaust cooling holes and tested again. Even with 145 psi no leaking. Glad the head is fine!

 

[MaxHO]

I continued to check the crankcase/ engine block. There was a crack which I had repaired approx. 6 years ago at the exhaust side. After removing the head studbolts, I filled the coolant jacket with water. Then airpressure the studholes and yes from two studholes the bubbles appread in the coolant jacket! There must be water creeping along the studbolts and enter the oil side at the headbolts. So I watertighted the studbolts by locking agent for the tread and Elring Dirko HT sealant (High Temp resistant 599F) and in addition an O-ring at the top. Everything flush with the head surface. The studs still has the freedom to I expand at operating temperatures. I hope measure this will separate water from the oil. I will keep you informed.

 

[MaxHO]

The coolant jacket has corroded at one spot and the head to block mating area is became smaller. So I decided to use Permatex Copper Spray-A-Gasket (Spay can) to improve the sealing performance. Gives the original black multi steel gasket a nice golden appearance.