Horrible sound coming from motor...

2014 Merc 150 Pro XS

Put her in the water, ran about 3 miles around top speed with no issues (other than the wind knocking my kill switch cord out about 3 times), slowed down and trolled looking for some good fishing spots when after about 8-10 minutes the motor started idling funny for about a minute and then choked and shut off. Cranked it back up only to hear a god awful, high pitched squealing/slight grinding (best way to describe the noise) as it struggled to stay fired up only to choke out again. Would turn over every time but that same noise would present itself and the motor would die pretty much instantly. Called a mechanic nearby and he thinks it could be an air compressor but honestly after doing some research and watching some videos, the noise does not seem to be the same as motors that had bad air compressors. Just got this thing too. COME ON!!! Any ideas, fellas?

Might be belt tension pulley or any of the bearings, you better pray it's not a compressor or you'll be wanting to sell that Mercury for a Yamaha.

I am prepared to spend some cash.

Twas the compressor. 3 months out of warranty and Merc won't good will it. Ouch.

My Merc 250 stopped running and would grind when I tried to start her up. Turned out that the LU seal was blown and no oil so it siezed up. If your motor will actually run then that is not the problem.

That really hurts. I could tell from the noise that it was coming from the top of the motor when I was on the water.

Might pull the lower plug to check for water just in case. Water will be under the oil. Mine sounded like the grinding was at the top of the motor as well. Never know and easy to check.

That's going be an expensive fix if done properly. Replace compressor, both filters for the oil return lines, have direct injectors and fuel rail cleaned.
Failure to do the above could result in another failure to the new compressor, or powerhead.

best luck man you have been through it lately ..

And re-priming of the oil system. It's the reason that I will not repower my boat with another merc.

Oh and wait until you get to tackle the oil pump project.......

She's in the hands of Gary Hughes at Hughes Marine Service. I'm confident he's taking the necessary actions to get her primed and ready to hammer them feesh.

You had this engine for a month correct? May have been going before you bought the boat. Sorry for your problems, happened to mine but caught it before it blew.

Hard to say. It's run fine during the several times I've had it out since I bought it. Ran all day long each time with no issues. From the moment I noticed it idling funny to complete failure was about 15 minutes. That's it. No signs of any problems prior to that.

Happens not much you can do bought it. Other than that my 225 Pro XS has been excellent. Good luck.

I'm sure that will be the case for mine as well. Happy fishing!

Sent you a PM