Status Alarm Goes off over 3000 RPM????

[ISP197]

Volvo Penta V8-270-C-B - #A369760.......Here is my problem and any help is greatly appreciated. I can run my boat all day long below 3000 rpm and never have any issues. Once I go over 3000 rpm, it takes about 40 seconds and I will get a loud beep for three seconds or so. The beep stops, but my status alarm light (red in color with triangle shape) remains lit - not to be confused with the engine alarm (yellow shaped engine). Dash mounted temp gauge never goes over 160, oil shows full on the dipstick, and no noticeable decrease in the volt meter so everything appears fine based on the gauges. The engine never looses power or goes into limp mode. It continues to run as normal, just with the red warning light remaining lit. As soon as I go below 3000 rpm, the red light goes out. The longest I let it go before doing this was maybe 20 seconds. I have had the codes read and I got the following: Exhaust Manifold Water Temp 1 EMWT 1 Temp High 1, Exhaust Riser Water Temp 1 ERWT 1 Temp High 1, Exhaust Riser Water Temp ERWT 1 Temp High 2, Exhaust Riser Water Temp ERWT 2 Temp High 1, and Exhaust Riser Water Temp ERWT 2 Temp High 2. I am assuming the same codes are just two separate incidents, but not sure. The mechanic said that he thought Volvo had some issues with bad sensors but when he ran the engine serial number there were no bulletins. He was kind of stumped and advised he was going to contact Volvo and see what they thought. On a side note, that was a week ago and I am still waiting to hear back from him. I replaced the impeller last spring and I have never had any issue with the motor until now. The motor has right at 300 hours, all in fresh water. Any insight or assistance is greatly appreciated!!!

 

[muc]

What kind of advice are you looking for?
Are you a do it yourself or do you want to lead the mechanic?
Have you owned the boat since new?
What part of country do you boat in?
When were the exhaust anodes last checked/ replaced?

Your symptoms are fairly common in my area, I’m very surprised your tech is confused.

 

[ISP197]

I generally do the basic maintenance but I will probably let the mechanic take this one for fear of messing something up worse. I have owned the boat since new and it has only been in Midwest lakes. I doubt the exhaust anodes have ever been checked. Is this something easy?

 

[muc]

The exhaust manifolds on your engine are expensive, because of this Volvo includes 4 sacrificial anodes in them. These are supposed to be checked every 100 hours or once a year, which ever comes first. If done every year it is easy. If they are left longer, then it can become much harder. Just like the props and drive.

The manifolds are aluminum and the bolts are steel. So they can get seized and require penetrating oil or heat to keep from snapping them. And you don’t want to snap them. Your operators manual will have a nice picture of their location and the torque specs. Volvo sells a kit that should have everything you need. They need to be replaced once 30% is used up. This is definitely a “pay me now or pay me much more later” situation. Like I said these manifolds are expensive.

The reason i asked how long the anodes have been lasting, is it would have given me a better idea of what is causing your symptoms. There are a few things that determine how long these anodes last and what other problems you will have with the exhaust manifolds. Water P.H. (Soft, hard or neutral) and how much vegetation or silt is in the water. And of course whether or not the engine was stored with the proper antifreeze. We are now starting to see issues from people who used the-50 pink nontoxic antifreeze that most big box stores sell. Another example of saving $10.00 only to have to spend $1,000.00s later.

Because this is a catalyst engine. The exhaust manifolds need to run at a consistent temperature. On these first generation catalyst engines, Volvo used thermostats in a plastic box bolted to the side of the manifold. The first run of these (I’m guessing what you have on this engine) had a few issues so Volvo redesigned them and we are seeing less problems. I would recommend taking a close look at these if your manifolds haven’t started rotting due to lack of maintenance.

One other thing. The warning lights on your dash. For this engine the light that looks like a engine means there is an emissions problem when it lights up. The one that has the triangle lights up when ever a trouble code is set. When one or both lights come on with the warning horn at the same time, it means it’s pretty serious and the engine goes into “derate mode” There is derate 1, derate 2 and forced idle. You don’t think it is going into “limp” mode but it is. The fact that the light and horn turn off when you reduce the throttle to below the activation threshold means you are in derate 1. If you were in derate 2, you have to reduce throttle to idle to turn them off. And when your in forced idle, you have to shutdown the engine to come out of it.

Servicing the anodes and exhaust thermostats might be something that you want to attempt. The only tool that I can think of that the average DIY person might not have, is an inch pound torque wrench. This job requires a torque wrench that is accurate between 50 - 100 in. lbs. this is very important.

Hope i have helped. If I can explain anything better, just ask.

 

[ISP197]

Do you thing that by changing the anodes and exhaust thermostat’s it will solve the problem or is this just a good place to start? I greatly appreciate your experience and advice, thanks.

 

[muc]

Checking and changing (if needed) anodes is like changing your oil. It’s preventative maintenance, it’s not likely to fix a problem.

I try to not recommend parts replacement without testing. 2 of these thermostats are over $300. But if they are the first design, I would lean toward replacing. Here is how they work if you want to test.

The water comes out of the engine thermostat housing and goes to a T. One side of the T goes to the exhaust manifold and the other side of the T goes to the manifold thermostat. The thermostat has 2 inlets and one outlet. The hose is one inlet and the other inlet is a passage where the thermostat bolts to the manifold. The outlet is a hose that dumps the water to the elbow. When the manifold is cold, all the water goes straight through the thermostat to the elbow. Only a very very small amount of water goes through the manifold due to a small air bleed hole in the thermostat. As the manifold starts to warm the thermostat will progressively allow more water out of the manifold to keep it at the right temperature.

The thing that would keep me from replacing them without first troubleshooting. It appears that both have failed at the same time. This isn’t unheard of, but is rare. It would have been nice if whoever did the engine scan would have looked just a little deeper and told you when the faults happened.

Sorry i can’t give you a simple answer. But so much depends on how your boat has been cared for and the water you use it in. It is almost always best to get advice from a knowledgeable local tech who knows your boat and how you use it.

 

[ISP197]

I will see what direction my mechanic wants to head in while keeping your advice in mind. Hopefully he has the same thoughts. On a side note, I don’t often ask questions but I visit this site often and have learned a lot by reading the forums. So I greatly appreciate the fact there are people who are willing to try to help out with other people’s problems.