Black Max will not run right

[Junk Yard Dog]

We have a black.max 150 that refuses to run right. The engine when cold will take of and wail like it is supposed to. Once hot it refuses to take off or spool up so to speak. Been thru the entire fuel system and even installed an electric fuel pump set to 6 psi and still no joy. The year of the motor is approx 1989. Have also installed two new switch boxes and a new stator assy. Have checked timing and all seems to be good. I am beginning to think this thing is afraid or the water. It does not do this when we are running it in the yard. HELP PLEASE I have always concidered my self a good mechanic but this thing is making me think twice

 

[Dukedog]

Have ya tried "bumpin'" tha enrichner? Even with tha 'lectric pump its still gotta get past tha carbs..........

 

[Junk Yard Dog]

Yes we have done everything possible except changing out the carbs.Even pulled the heads and installed new gaskets. I am a Machinist by trade and took the heads and chucked them up on my mill to make sure they were not warped, bead blasted them and reinstalled. I have had the carbs apart and cleaned them up no change other than i had one of the floats to high be took the carbs back off and fixed that. Still no change. I set the timing by ear til it sounded right and set the idle and like i said this thing will scream out of the water no problems seems the load of moving the boat has to do with the problem. And BTW thank you for your response. And the boat will slowly take off pushing the choke.We have rebuilt the mechanical pump and it seems to be working but then again i installed the electric pump an i swore up and down it would fix it. I know it is a fuel starvation problem

 

[Dukedog]

set the timing by ear til it sounded right and set the idle

If ya mean max, that won't work. Max needs ta be set at 22 degrees "crankin' speed. Idle timin' is set with tha motor runin', in tha water in gear. If ya still have tha timin' module get rid of it, as in trash it, before ya set any timin................idle timin' is tha ONLY thing that determines idle speed.'

 

[Junk Yard Dog]

If ya mean max, that won't work. Max needs ta be set at 22 degrees "crankin' speed. Idle timin' is set with tha motor runin', in tha water in gear. If ya still have tha timin' module get rid of it, as in trash it, before ya set any timin................idle timin' is tha ONLY thing that determines idle speed.'

No not set to max. Just set it in the yard till it sounded better. Im old school used to use car antennas to set timing and idle no ant. then set by ear. There is no module just the mechanical timing

 

[Dukedog]

Understand tha old school stuff but a lot of that won't work on these things, They get ta actin' like a woman sometimes, get kinda "finiky". Set it like described and ya good ta go on that part. If it still acts stupid ya can look at something else cause timin' ain't it..........Oh yeah, tha idle ends up where ever you and tha motor or happy, usually not where tha "book" says.........

 

[Junk Yard Dog]

Understand tha old school stuff but a lot of that won't work on these things, They get ta actin' like a woman sometimes, get kinda "finiky". Set it like described and ya good ta go on that part. If it still acts stupid ya can look at something else cause timin' ain't it..........Oh yeah, tha idle ends up where ever you and tha motor or happy, usually not where tha "book" says.........

I thank you a lot my good man. We have two spare motors i just pulled the carbs off of one and will rebuild them tomorrow and install, then take a trip to the bay with timing light in hand. I will continue the post after we see what happens. Hate to think this thing is scart of the water

 

[Dukedog]

Don't really need it on tha water. Tha max can be set at just crankin' speed (all plugs removed 'cept # one) in tha yard. Idle is set "by ear" ya might say. Its done motor runnin' in tha water, in gear, Ends up where ever you and it are both happy, Usually 700 ta 800 rpm.. Just make sure its just above tha luggin' sound.......gl

 

[Junk Yard Dog]

Don't really need it on tha water. Tha max can be set at just crankin' speed (all plugs removed 'cept # one) in tha yard. Idle is set "by ear" ya might say. Its done motor runnin' in tha water, in gear, Ends up where ever you and it are both happy, Usually 700 ta 800 rpm.. Just make sure its just above tha luggin' sound.......gl

Go it my friend. Thank you again for your help I will post tomorrow after we see what happens.