Mercruiser 5.7 EFI 2000 with Bravo 1 alarms above 3000 rpm

[2000SEARAY280SS]

I own a 2000 280 SS Searay with twin 5.7 throttle body EFI Mercruisers. When running at 2900 RPM and below everything is fine. If I push on to 3000 or above I will soon hear a beep that recurs every 10 to 15 seconds. I have replaced the temp sensor, impeller, and monitored the water flow to the engine from the seawater pump using a clear hose. I used an IR thermo gun to measure the temp of all of the normal hot spots and they read the same as the port engine that does not alarm. The oil presure at 3000 reads about 50 and the temp gauge is around 175 to 180 but the thermostat housing runs about 150 to 160 with the termostat open. My manual says that only the out drive, temp, and oil presure sensors are connected to the alarm. And this forum said that an intermitant beep was the out drive sensor and that disconnecting it would cause the alarm to stop. well that did not work. My conclusion was that it must be something else. Since the oil pres is good.

:huh:
Any ideas as to what else can cause a beep related to the RPM's?

 

[2000SEARAY280SS]

I have another question on this subject. What sensors can cause the delayed beep I get? It goes on and off. I am under the impresion that a solid beep is for oil and water and the spaced beep is for the out drive fluid. Are there other sensors that can cause the system to beep on and off?

 

[Turtlesboat]

there should be 3 kinds of alarm beeps, 1 solid, 1 rapid repeating, and the other is what's called a 2 beep which happens every minute. at least that's the way it is on my 280. the first two need swift and immediate attention. the 3rd is a warning that something isn't right but probably won't melt your engine. The most common cause cause for the 2 beep is the IAC valve, (search and ye shall find info). Other than that, I'm not sure what else triggers this alarm. A sure way to find out is to hook up a computer and see what's triggering it.

 

[2000SEARAY280SS]

Thanks for the tip. I have a procedure for checking the IAC sensor. I will run it this weekend and let you know what happens.

It is also good to know there are more things to check. I was going :smt101

 

[Turtlesboat]

Just found out that there are 17 things that will trigger a two beep alarm on my boat.

 

[2000SEARAY280SS]

Just ordered the Rinda scan tool for the Mercruiser. Figured since I like to work on my own equipment and their are no certified Mercruser mechanics locally After a couple of sensors it will pay for its self. On their web page is the user manual and depending on the MEFI unit you have there are a lot of codes.

http://www.rinda.com/marine/marine.htm

Where did you find the list of things that will cause the beeps? I did not get a Mercruiser user manual since I bought this boat used. I thought about ordering one from Mercruiser for 20+ bucks.

Also I think my beep is more like the out drive beep and I am going to swap the two sensors between my two engines.

I'll keep you posted.

 

[Turtlesboat]

I found the list in the mercruiser repair book that I bought at a bookstore.

You can test the outdrive lube sensor by grounding the wires together. unplug the wires that go to the reservoir, attach a small wire between the two wires that go to the computer and it will trigger the lube alarm so you can hear what it sounds like. It's a very rapid repeating alarm that will get your attention. You can do the same thing with the temp sensor and the IAC sensor so you can get an idea what each is doing. Once you know what each alarm sounds like, you can then proceed to find out which sensor is triggering the alarm by unplugging the appropriate sensor for that type of alarm until it stops. then you've found what is triggering it. But since you bought a code reader, that will definitely help in finding the problem. But no need to swap the reservoirs, just unplug one end of the wire, if it's that sensor, it will stop.

 

[Hampton]

In these days of electronics, they very easily could have put a plain-english display with all of the monitored systems integrated.

Example: Alarm- "BEEP BEEP" - Display - "Stbd Drive Fluid Level Low"

 

[Turtlesboat]

But then what would the techs do with those expensive computers to read the codes?

 

[2000SEARAY280SS]

I thought that I had read about pulling a lead from the lube resevoir would disable the alarm. I tried that the last time I was out and the alarm did not stop. But it is a good idea to short the leads to get a sense for the tone and pulse of the alarm.

Did not make it to the boat today.

I am having second thoughts about the code reader but since it covers so many engines I guess I can help out some fellow boaters.

 

[2000SEARAY280SS]

Well I hooked up the scan tool today and it is really cool. It showed all of the history codes and the status of the system. It came with a cable long enough that I could leave it hooked up and do a sea trial. I cleared the codes and set out on the river. Temp good oil pres good rpm good ran it up to 2900 no alarms. Pressed on to 3100 and beep here came the alarm. Backed down and checked the codes. 44 "cannot read the knock sensor" "alarm active"

Wow this is great. Headed back to the dock and started to check it out. To my surprise when I searched between the twins there near the water intake hose way down under and in back was a little blue connector hanging free. I reached around under the riser and found the sensor post and pluged it back in.

Had to go back to work so I did not get a chance to check it but I am pretty sure this is it.

 

[Turtlesboat]

That's awesome. I wish they made one for the mpi engines.

 

[boatdoc100]

I thought that I had read about pulling a lead from the lube resevoir would disable the alarm. I tried that the last time I was out and the alarm did not stop. But it is a good idea to short the leads to get a sense for the tone and pulse of the alarm.

Did not make it to the boat today.

I am having second thoughts about the code reader but since it covers so many engines I guess I can help out some fellow boaters.

Pulling the plug will not diable the alarm(if that is the problem). The circuit must be jumped out to test what you are trying to do. Simply jumper the 2 pockets in the plug together to do the test properly.

 

[boatdoc100]

The scan tool is worthless without the tech manuals we get in school. Many things will set a single code.

 

[2000SEARAY280SS]

Well that fixed it. Matched the code in the reader just fine. Spent all day on the smooth as glass Potomac river caught a small blue and a nice 34 inch striper. Yum. Got a chance to check out my new electonics from Jim at BOE. Life is good. Thanks for the help.

Top end was 42 SOG. Sweet. No other alarms. Except for the fuel low indicator )