2004 sx230 overheating & milky cream in vent tube

[c_johnsonftw]

I have a 2004 Yamaha sx230 and the starboard motor keeps setting of temperature warning light on dash. I bought the YDS and ran it through diagnostics with engine off and it said check thermostat and cooling system. I replaced thermostat, replaced 1 temp sensor just to see, replaced spark plugs, I went through every cooling line inside and out, went through the entire exhaust system checking for clogs as this boat was run in salt water then put in storage for years. I’ve flushed both engines repeatedly with salt away and port engine can run 20 min on hose no issues. The starboard overheats after maybe 4 min. Plenty of water coming out exhaust hole by jet pump, engine water outlet above jet pump and from the exhaust by jet pump. Water comes out of rear pisser while on hose sometimes with steam, I switched gauges just to see and same light pops on. I started ripping hoses back off to recheck everything. I took the hose off of breather from oil reservoir and blew it out and a bunch of thick white paste came out. I opened oil cap and there is some white paste around cap. I looked at oil and it seems thin but can’t see anything white in actual oil. My next step is to pull motor out and tear down top end to check head and head gasket. Also now there is a milky puddle sitting in air cover box under fuel rail that is very thin almost watery light brown milky look. Possible injector issue? Please help and I’d love to hear suggestions before I pull head off. Engines only have 37 hours and boat sat unused for a while in dry storage. Again I haven’t ran it in the lake only on hose

 

[WREKS]

It was overfilled with oil. When there is too much oil in oil cooler, it gets pumped out of the tube at the top of the oil cooler that goes to the oil separator. From there it gets pumped up the tube coming up into the air box.

Running on hose and aiming a temp gun below exhaust manifolds is a good way to see if cylinder water jackets are clogged. If temps get over 200F, head will probably have to be removed to mechanically scrape cylinder water jackets. This is not a salt problem. This is a microbial buildup from residual flushing water left in the cooling system.

Doing compression and leak down tests are very helpful in determining if there is a breach somewhere in the cylinder head.

 

[c_johnsonftw]

It was overfilled with oil. When there is too much oil in oil cooler, it gets pumped out of the tube at the top of the oil cooler that goes to the oil separator. From there it gets pumped up the tube coming up into the air box.

Running on hose and aiming a temp gun below exhaust manifolds is a good way to see if cylinder water jackets are clogged. If temps get over 200F, head will probably have to be removed to mechanically scrape cylinder water jackets. This is not a salt problem. This is a microbial buildup from residual flushing water left in the cooling system.

Doing compression and leak down tests are very helpful in determining if there is a breach somewhere in the cylinder head.

 

[c_johnsonftw]

I appreciate your reply! A compression check was done and compression was good. I did use a laser thermometer while flushing and temps did exceed 200. Port engine was running around 175. Is it not odd that 1 engine would be doing this and not the other? I just ordered gasket kit so I can pull head and visually inspect. Is it easier to pull engine and do this? I’m tired of laying across engines and kneeling over in hatch.

 

[WREKS]

No it is not odd. I would run starboard on hose at no-wake or idle and shine exhausts. The overheats temp should show up within 4 minutes. Cylinder #1 is the farthest from the cooling water intake to the cylinder water jackets and is often overheats first.

If there is a small breach in head, a compression can often out pace the leak. That is why leak down can be more helpful in diagnosis.

Pulling engines is best, but you need to get set up to do that. It is not easy. I would try to get a good idea what problem is before removing engine.

 

[c_johnsonftw]

No it is not odd. I would run starboard on hose at no-wake or idle and shine exhausts. The overheats temp should show up within 4 minutes. Cylinder #1 is the farthest from the cooling water intake to the cylinder water jackets and is often overheats first.

If there is a small breach in head, a compression can often out pace the leak. That is why leak down can be more helpful in diagnosis.

Pulling engines is best, but you need to get set up to do that. It is not easy. I would try to get a good idea what problem is before removing engine.

 

[c_johnsonftw]

I really do appreciate all of your input. I’m headed to get leak down test kit now, before going any further. I have the hoists and equipment to pull engine and I’ll build a cradle for it if need be. I’m by no means an expert mechanic but I did stay at a holiday inn express once. In all seriousness I’m pretty mechanically inclined but this is my first experience with marine and Yamaha engines

 

[WREKS]

First you need to run starboard engine on the hose as stated above.
How is it that your engines have only 37 hours?
Is boat a 2004 or 2008?
Do not proceed without a service manual!
Read service manual!
If engine needs to be removed, check coupler clearance to determine whether additional shims will be needed when reinstalling.

 

[Brad_Ct]

I would pull the anode out(left rear under exhaust manifold) and that will allow you to see if there is any build up in the water jacket. There is also a cooling water bypass valve in the same area that could be full of crud not allowing it to function properly.

 

[WREKS]

Cooling water bypass valve?

 

[c_johnsonftw]

First you need to run starboard engine on the hose as stated above.
How is it that your engines have only 37 hours?
Is boat a 2004 or 2008?
Do not proceed without a service manual!
Read service manual!
If engine needs to be removed, check coupler clearance to determine whether additional shims will be needed when reinstalling.

 

[c_johnsonftw]

It is a 2004 sx230 and YDS verified 37 hours and they are original motors. Boat is extremely clean other than this issue. Guy who owned it died and his brother kept it in storage and never used it is what I was told.

 

[Brad_Ct]

Cooling water bypass valve?

Yes, Parts 21 to 31

 

[c_johnsonftw]

I would pull the anode out(left rear under exhaust manifold) and that will allow you to see if there is any build up in the water jacket. There is also a cooling water bypass valve in the same area that could be full of crud not allowing it to function properly.

 

[c_johnsonftw]

Thank you for your input as well. I’ll check the bypas valve and pull the anode as well. I’ve actually got all the lines pulled off and can access that now before re assembling and running it to do leak down test.

 

[WREKS]

Thanks @Brad_Ct.

 

[c_johnsonftw]

After looking at picture closet I already checked the bypass valve. It did have some buildup around the black plastic pressure control valve inside. I cleaned it up and put it back together the first time I pulled all the cleaning lines off. I read in a separate thread about the inner gasket and rubber coupling with the 2 hose clamp bands inside exhaust elbow boot and if it is deteriorated or leaking it could allow water to get into head. Is this true? These are pretty old and could be in better shape

 

[WREKS]

@Brad_Ct Where does Part #32 (hose) bypass to?

 

[c_johnsonftw]

@Brad_Ct Where does Part #32 (hose) bypass to?

 

[c_johnsonftw]

It’s currently off. I’d have to look at where it’s connected on other engine. Are you thinking I routed it wrong in my first attempt checking all the cooling lines?