Mercury 150 Black Max

[sschefer]

Re: Mercury 150 Black Max

Great Info man thanks alot. I looked over my fuel line assembly- pretty good and have no visible leaks/holes. Spark plugs are 2 years old at most w/ very little hours on engine. Because of the response to my problem (greatly appreciated) I'll give you more detalil. The boat runs great outside of a slow idle to moderate idle. Runs great going fast. But ANYTHING under a stationary idle to slow idle (i.e. parking in a marina) the engine will DIE. VERY frustrating!! Thanks for the help

So Hoovy, does this mean it's not hard to restart after fishing like it was in the first post? Or, is this just a continuation of the original problem. If it's added info then that changes things. I'd be looking for a bad cylinder or bad reeds now. FYI #5 is the usual suspect.

 

[Dukedog]

Re: Mercury 150 Black Max

I've had this boat 3 years now. Its always had trouble starting and idleing. I've paid big money to have it serviced and its reaped little results. Carbs have been re-built, new fuel pump/filter. It runs great when she's wide open, but I will fish for a bit and when I try to start back up it won't. I nearly drain my cranking battery every time. Could it be a fuel line problem?

Any feedback would be greatly appreciated, thanks!!

This is gonna be something minor. If it wasn't it would have already turned into something major after 3 years ie: bad clyinder.

I'll ask again. How do you start tha motor? How do you use tha enrichner? Does it work? What trim angle at start? What trim angle at idle? Does it run ok at 1000 rpm? 1500 rpm? What is tha LOWEST rpm that it runs like it should? These ?'s will give clues as to what is going on.................

 

[sschefer]

Re: Mercury 150 Black Max

This is gonna be something minor. If it wasn't it would have already turned into something major after 3 years ie: bad clyinder.

I'll ask again. How do you start tha motor? How do you use tha enrichner? Does it work? What trim angle at start? What trim angle at idle? Does it run ok at 1000 rpm? 1500 rpm? What is tha LOWEST rpm that it runs like it should? These ?'s will give clues as to what is going on.................

Yup.. Also do you have a good tach that can get you a fairly decent idle rpm reading. There is a possibility that it's just that your idle rpm is set too low. If you can get a hold of a tach that reads off a plug wire you can isolate all the other stuff that can give you bad tach readings. Idle is set using intial timing so if your tach is reading wrong (too high), someone may have adjusted the initial timing wrong and all the symptoms you describe could be the result. I run mine at 700 rpm others like to see it around 650.

 

[Faztbullet]

Re: Mercury 150 Black Max

Check the enrichner(choke) first to see if working and if it has the idle stablizer box,deep six it as it can mess with the low end timing. Check to see if its running on one bank as you posted" The boat runs great outside of a slow idle to moderate idle. Runs great going fast. But ANYTHING under a stationary idle to slow idle (i.e. parking in a marina) the engine will DIE" if you have a bad stator you could be only running one one bank and other bank kicks in when rpm rises. Also check and clean /replace the bleed restrictors as if they are clogged it will cause fuel to puddle in intake and foul plugs at slow speed causing a hard restart after running. Steel reeds do not go bad or loose tension, they break... and you cannot vacuum test a cylinder as you cannot seal off the exhaust port,clearance around piston,piston ring gap and crank seal rings even if you capped the intake and exhaust as you would be vacuum entire internals of engine.