Steam in strb Exhaust

[scottwvyc]

I have a 1980 37C with Johnson and Towers 671N's. I am seeing some steam while running coming from the starboard exhaust. Oil analysis showed elevated level of sodium, pressure tested coolant but found now leaks, so assuming raw water side. What may be the likely place to start looking for the culprit. Thanks Scott

 

[workingonadream]

does the steam have a sweet smell to it if it does then it is coolant. if not I would start with the exhaust. I would look at the risers/elbows first. how old are they and are they cast or stainless. the reason I say to sniff the steam is because I had an issue with excess steam and it turned out to be a cracked manifold, but it always held pressure when I tested it. I knew I had a coolant issue, but I couldn't find it. so I would do the nasal appraisal first if it doesn't smell sweet, it is likely a raw water issue

 

[31FlyCruzr]

Steam to me is low raw water flow.

Check the raw water intake strainer first, then I'd be looking at the raw water pump.

 

[scottwvyc]

Steam to me is low raw water flow.

Check the raw water intake strainer first, then I'd be looking at the raw water pump.

Thanks for the replies. It is interesting you mention the strainers, because I did notice the other day that they looked like they needed cleaning out, the slip in my marina can get shallow at low tide, and I must have sucked in some mud from the bottom.
I haven't heard of this before and am curious, how does low raw water flow result in steam in the exhaust?
Thanks Again
Scott

 

[workingonadream]

under what conditions are you getting the steam, underway or at the dock. a clogged basket would mean a restriction in flow, which in turn would lead to a running hot condition. in any case I would definitely check the baskets, but also check the temp when running. if you are running at the dock only it will probably not run hot unless it is a big obstruction ,but if you are underway with an obstruction, the temp should shoot up rather quickly. good luck

 

[scottwvyc]

under what conditions are you getting the steam, underway or at the dock. a clogged basket would mean a restriction in flow, which in turn would lead to a running hot condition. in any case I would definitely check the baskets, but also check the temp when running. if you are running at the dock only it will probably not run hot unless it is a big obstruction ,but if you are underway with an obstruction, the temp should shoot up rather quickly. good luck

Thanks for the reply, while underway it does not run hot, same temp as the port side. Steam is only present while underway, and is gone at idle.

 

[workingonadream]

I would have to say that you can eliminate your baskets and impeller as you would most definitely be running hotter than normal if you had a restriction. I would go to the exhaust now, preferably the risers, but you will have to pull them to inspect.

 

[saltshaker]

Thanks for the reply, while underway it does not run hot, same temp as the port side. Steam is only present while underway, and is gone at idle.

I had a similar problem on a 6V92TA. Coolant was leaking into the exhaust from a bad riser. If you are loosing coolant you should smell it and the coolant level would be dropping. I wouild talk to a Detroit mechanic ASAP and find out what the elevated sodium in your oil might indicate. Little problems can cause significant damage if not addressed right away.

 

[workingonadream]

I have 8v71s my risers are raw water cooled, but the same can be happening as with the last post, only with raw water. in other words if the exhaust and raw water are mixing before the shower head ,it is not a good thing,and can do damage to the motor. I had to put a set of gas jobs in my brother inlaws boat because he neglected his exhaust. I would definitely pull them to inspect.

 

[scottwvyc]

I had a similar problem on a 6V92TA. Coolant was leaking into the exhaust from a bad riser. If you are loosing coolant you should smell it and the coolant level would be dropping. I wouild talk to a Detroit mechanic ASAP and find out what the elevated sodium in your oil might indicate. Little problems can cause significant damage if not addressed right away.

Thanks for the reply, I am not losing coolant, and there isn't any coolant smell to the steam.