Mariner 150 looses power

[patrickj]

Ive got a late 80's mariner 150. It runs good 90% of the time but on occassion it just has no power, full throttle it wont even spin fast enough to plane out, sometimes as bad as not even taking off. Ive noticed when it isnt working my volt gauge shows 12.6 volts but whenever its running fine it shows 16-18 at idle or full throttle. So im thinking its something electrical. I replaced the stator and the rectifier, carbs rebuilt a few months ago, new fuel lines and filter, starting battery is fairly new. Could this be my power packs?

 

[Bosunsmate]

Re: Mariner 150 looses power

It could be the rectifier temporarily ruining the electrical system somehow
Does it look ok, not burnt/clean ground?
You can check it by doing a search for the test on this site

 

[aussieflash]

Re: Mariner 150 looses power

Thats about normal range 13v - 17v for an unregulated system.It builds with higher revs...ie low at idle and pegs at 17-18v at WOT.
First thing I would do is check spark.

 

[patrickj]

Re: Mariner 150 looses power

sparks fine on muffs, but it doesnt ever run bad in the yard, we had a intermitten spark on 3 cly... turned out to be the stator, so we replaced stator and rectifier, boat runs 90% of the time where as before it wouldnt even take off but since we replaced those parts its alot better but occasionaly something is cauing it to not run right. Im convinced its spark related because as i said everytime it starts acting up the volt gauge shows lower than normal, I guess my question really is where does the gauge get its reading, is it after the powerpacks? or does it read staright off the rectifier?