Issue with Mercury Outboard

[Chance Love]

So we have a 2007 Champion with a 2007 Mercury 150 on it. It has been FLAWLESS until a few weeks ago. It has happened only 4 times, but it drives me nuts. Sometimes when we first get on the water we will idle away from the ramp and then when you hammer the throttle, it will sound an alarm and just "bogg down". So we idle again for a second or two then hammer it again and it's good to go. And it's not just on the first run of the day, it has happened after several runs. Like I said, it's only happened 4 times in the last few weeks so it's very intermittent. This motor runs GREAT and starts on the first crank every single time. Now just have this annoying little issue. Any ideas?

Please save all the "because it's a Mercury" comments.

[Goldeneagle]

I'm not a boat motor guy, but it kind of sounds like a fuel filter.

[RiverRat1]

People don't like Mercury motors?

Don't know the issue. Hope the alarm is not the oil alarm.

[hntndawg]

Solid beep alarm or a certain number of beeps in a row? Constant should mean it thinks it has an overheat issue. Could be real, like thermostats sticking or weak impeller. Could be false alarm, shorted wire or bad sensor. The boggin down could be ECU shutting fuel down thinking there is an alarm condition.

[Walker]

Could be prop blow-out and over rev alarm. If your prop has the black cavitation buttoms make sure they are all there.

[CoolHandLuke]

Are Mercury’s the ones that have the issues with the high pressure fuel pump in the small secondary tank. I had this discussion a few weeks ago and it sounds exactly like the issue he had.

[glen]

Put new filters in and I would open the drain on the back of the motor afterwards. I think Mercs have them - It will be about a 6 inch hose that looks like it is out of place- open it up and see if you get fuel and water mixture. Best bet would be go get code read and see if it is "Fuel Vent" or similar code being thrown. As Walker has said it could be rev alarm if you are blowing prop out.

[hntndawg]

Oh yeah, you will also get a solid beep if the oil tank thinks it is near empty, and that will cause the ECU to limit RPM as well. (Based on me assuming you have an 2 stroke EFI) I would think prop blow out would not be described as "bogging down" You would hear RPMs increase and see so on tach before it hit rev alarm.

[kaizen]

I had a similar issue sounding issue with a 2007 225 optimax. Would run fine and always idle. On occasion getting up on plane the engine would cut power. Like running hard into engine protect mode. Sometimes a beep. Sometimes not. Always occurred around the 3000 rpm. Sometimes, it would get up on plane on the second or third attempt. Sometimes, it would act exactly like it was in engine protect mode and cut power anytime rpm hit 3000 till I limped back to dock and took it too a shop. Never tripped a code. Lots of head scratching on it. Shop finally diagnosed it as having to do with the crank position sensor. Havent had that problem since. The only thing I really learned through the process is if something quirky happens on a optimax replace your battery with the biggest most powerful one you can get and see if it helps.

[MacDaddy67]

fuel pump has trash in it....My Mercury has an accelerator pump that was full of gunk...

[Dru]

Did it get low on oil? There is a small oil reservoir on the motor. If it has air in it then the alarm will sound. Mine got low and i filled the oil container but air got in the reservoir and would hit the sensor when i was trying to get on plane (tilted motor). Took forever to figure it out.

[adam_p]

Next time it does it try pumping the bulb and see if that fixes it. Mine would bog down and die when I tried to get on plane after a long idle. Lift pump was bad.

[AHF]

Check the impeller, I have an 2017 150 hp mercury and it does have the same failure, water presure was low.

check the oil level in the tank inside the engine, some times the float does get stuck.

[BertramBass]

Are Mercury’s the ones that have the issues with the high pressure fuel pump in the small secondary tank. I had this discussion a few weeks ago and it sounds exactly like the issue he had.

My 2010 had this issue. It acted just like the OP's and went from doing it every once in a while to unable to get on plane at all. Mechanic pulled the shroud and ran it in the shop with his hand on the secondary tank. It started getting hot and he said the pump was the issue. They installed a new one and I haven't had any more issues.