So I got it figured out and fixed. It was the throttle position sensor (TPS). Another common cause is the shift interrupter switch, which many call the neutral safety switch. This switch is on the motor, not the neutral safety switch in the remote. If you have loose throttle cables because they have been stretched over time it can also cause faulty TPS readings. Mercury’s suggestion was to replace the lower throttle cable, which I will probably have done as well as I’m only getting about 5000 RPM’s, when max is 5750. At least it works again, have been chasing this problem for a couple years.
Hi, I have the same outboard and as similar issue. Idle is ok, when i hit above 2500rpm i get constant beep and guardian mode. However if i manage to get on the plane quicker and throttle up faster its fine and runs at WOT fine. Do you think this could be the TPS? Thanks.
I’m having the same problem on my optimax. You should do a video explaining how you fixed it and what other things can be wrong like the neutral switch. But I found this video very informative as I thought I was getting a water coolant warning due to worn impeller. Turns out impeller was fine and just left it at that. I still run it but I have to use the 19 pitch blade to have some speed. It starts beeping after 32mph But 30 mph is plenty fast where I boat.
Great information here thank you....I will try your advice ....my ailments are 2006 115 Optimax. Goes into guardian mode and throws 8 different random codes in no particular order. I can clear the codes with vessle view app but boat will beep and not go over 10mph. 2091-23 guardian due to overspeed. 541-24 water temp. 701-24 oil tank A level. 711-24 oil level. 451-25 pitot pressure. 555-24 Air comp temp. 2092-23 neutral overspeed. 1012-25 trim pos.---Water pump replaced and flowing great. Only has one oil tank on top of engine always full and currently oil sensor is bypassed. Swapped out water temp guage. New spark plugs. Oil pump pressure confirmed. Starts and idles great but will not rev up much higher than 3500 rpm without faulting out.
I have the same issue on my Optimax 90, I got a new neutral switch sensor yesterday and will change it next week. Hopefully the problem is solved after that.
Not yet, still working on it. Replaced the oil tank and that didn't do it. Last thing he tried was to disconnect trim sensor, but that didn't work either. Next thing we're going to try is throttle position sensor.
@@TheMuskyManiac I think it is your throttle position sensor. I was thinking crank sensor but the engine wouldnt run properly at all. So throttle position 98% sure. Water pressure limits to 1250 rpm. Could be a coolant sensor you should have 1 on the cylinder head. I had the wire pulled out of mine and I would get the exact same beep at 4000+ rpm on mine. So if its not the tps its the coolant sensor.
Thank you sir , my 115 started doing the same , and with your video I fixed straight away
So I got it figured out and fixed. It was the throttle position sensor (TPS). Another common cause is the shift interrupter switch, which many call the neutral safety switch. This switch is on the motor, not the neutral safety switch in the remote. If you have loose throttle cables because they have been stretched over time it can also cause faulty TPS readings. Mercury’s suggestion was to replace the lower throttle cable, which I will probably have done as well as I’m only getting about 5000 RPM’s, when max is 5750. At least it works again, have been chasing this problem for a couple years.
Hi, I have the same outboard and as similar issue. Idle is ok, when i hit above 2500rpm i get constant beep and guardian mode. However if i manage to get on the plane quicker and throttle up faster its fine and runs at WOT fine. Do you think this could be the TPS? Thanks.
That spunds like the sensor in the oil tank possibly. Should be able to bypass to test. Have to replace whole tank id sensor is bad.@@adamblake2897
Check your safety switch inside the motor. There is a video...115 mercury running ruff at 3000 rpm. It was A simple fix for me.
I’m having the same problem on my optimax. You should do a video explaining how you fixed it and what other things can be wrong like the neutral switch. But I found this video very informative as I thought I was getting a water coolant warning due to worn impeller. Turns out impeller was fine and just left it at that. I still run it but I have to use the 19 pitch blade to have some speed. It starts beeping after 32mph But 30 mph is plenty fast where I boat.
Great information here thank you....I will try your advice ....my ailments are 2006 115 Optimax. Goes into guardian mode and throws 8 different random codes in no particular order. I can clear the codes with vessle view app but boat will beep and not go over 10mph. 2091-23 guardian due to overspeed. 541-24 water temp. 701-24 oil tank A level. 711-24 oil level. 451-25 pitot pressure. 555-24 Air comp temp. 2092-23 neutral overspeed. 1012-25 trim pos.---Water pump replaced and flowing great. Only has one oil tank on top of engine always full and currently oil sensor is bypassed. Swapped out water temp guage. New spark plugs. Oil pump pressure confirmed. Starts and idles great but will not rev up much higher than 3500 rpm without faulting out.
You have to shunt or to replace the neutral switch sensor under the oil tank
Is that different than the throttle position sensor?
It was the TPS.
I have the same issue on my Optimax 90, I got a new neutral switch sensor yesterday and will change it next week. Hopefully the problem is solved after that.
Any luck with your fix? I am putting in a new TPS this weekend to see if this fixes the problem.
@@TheMuskyManiac It will take 1 week before I can try if it was a success. The boat is still on land! 😀 I will send an answer as soon as I know.
Fixed. Was the TPS.
I have also fixed my problem, it vas the neutral switch sensor for me!
The oil tank sensor is 4 beeps, they plugged in a diagnostic tool to see the errors?
Coolant sensor can cause this.
Mines doing exactly the same. Did you figure it out
Not yet, winter up here now, hopefully this spring they are going to try something else.
Head temp sensor
Did you find the problem?
Not yet, still working on it. Replaced the oil tank and that didn't do it. Last thing he tried was to disconnect trim sensor, but that didn't work either. Next thing we're going to try is throttle position sensor.
@@TheMuskyManiac Youre on the right track. Its either that a coolant sensor or water pressure sensor.
@@TheMuskyManiac I think it is your throttle position sensor. I was thinking crank sensor but the engine wouldnt run properly at all. So throttle position 98% sure. Water pressure limits to 1250 rpm. Could be a coolant sensor you should have 1 on the cylinder head. I had the wire pulled out of mine and I would get the exact same beep at 4000+ rpm on mine. So if its not the tps its the coolant sensor.
It has been fixed. Look at my newest reply.
@@colbybud yep.