2001 150HP Merc Stalls

[bumrunner]

I have a 2001 Mercury 150 HP Carburated motor that ran that has run pretty well all summer until today. I was having idling issues earlier in the year which caused it to stall at low rpms. I had a mechanic look at it and he said I just needed the idle adjusted. Well, that didn't help much and I was a bit weary about that. Usually that just covers a larger issue for a while. Well, a while has happened and I took her out today. She was really had to start (always has been a little hard, but today was extremely hard), and about 5 minutes after leaving the dock that was it, stall city. I could get her fired back up, but would stall after about 10 seconds. It does come equipped with an electric choke, and when I pushed it in it seemed to stay running until I let it go. As soon as I let go...stall city. The inline fuel filter was just replaced. Not sure what is going on here, but any help is appreciated.

 

[CharlieB]

Re: 2001 150HP Merc Stalls

Most probably it is simply time to clean the carbs completely.

HOWEVER, when ever an engine developes ANproblem the surest way to determine the root cause if to troubleshoot in a thorough and methodical manner.

Start with the simple, like test the compression, while you are cranking the motor for the compression tests also check spark on EACH plug wire using an adjustable gap spark tester set to a 7/16 inch gap. You want to see a bright blue arc that has a sharp CRACK. Compression #'s can vary depending upon the gausge used and actual cranking speed of the engine, so the actual # isn't as critical as having ALL cyl's within 10% of each other (the closer the better).

Once compression and ignition are verified then you can be sure that the engine is basically sound and your problems should be cured with careful cleaning and adjustment of the carbs and maintenance of the fuel system, rebuild the fuel pump, new filter(s), replace any hard, cracked fuel lines, primer bulb.

Repost your findings and any further questions.