Ignition Compatibility on 150hp Blackmax

[Dukedog]

QBhoy... tha orginal poster's motor is a '84 2.0 150 motor with '89 electrics like said....

your motor looks ta be at least a 2.0 135/150 ta at most a 2.4 175.. if heads are correct with year then at least '87.. it will have a build date in tha same place as described above... carb number (WH ?) will be able ta tell horsepower probably....

tha ratio could be different on it.. all 2.0 motors came (normally) came with 2 ta 1 gears.. everything else had 1.87 ta 1's.... only exception was tha XR4 and 6.. they had a smaller "barrel" and 1.78 ta 1 gears... could be tha difference ya seein'.. with tha age of these motors nowdays its not outta tha ordinary for tha gearcases ta have been changed somewhere down tha line.. they all will fit/interchange with all of 'em from '76 up including tha 2.5 motors....

 

[QBhoy]

QBhoy... tha orginal poster's motor is a '84 2.0 150 motor with '89 electrics like said....

your motor looks ta be at least a 2.0 135/150 ta at most a 2.4 175.. if heads are correct with year then at least '87.. it will have a build date in tha same place as described above... carb number (WH ?) will be able ta tell horsepower probably....

Thanks so much dukedog. Was hoping someone like yourself might reply. A friend used to know the engine from back in the late 80’s, when it was on its original boat. He remembers it being a 150, but different decals and writing perhaps. Thanks again

 

[QBhoy]

tha ratio could be different on it.. all 2.0 motors came (normally) came with 2 ta 1 gears.. everything else had 1.87 ta 1's.... only exception was tha XR4 and 6.. they had a smaller "barrel" and 1.78 ta 1 gears... could be tha difference ya seein'.. with tha age of these motors nowdays its not outta tha ordinary for tha gearcases ta have been changed somewhere down tha line.. they all will fit/interchange with all of 'em from '76 up including tha 2.5 motors....

Thanks also for this. It’s definitely the larger gearcase anyway, just with the props I’ve tan on it. Must find out more when next at it

 

[Dukedog]

tha ratio will only come inta play with how ya prop it for tha type performance your lookin' for... your set up (motor height, offset, prop), type and weight of your rig will be of tha utmost importance for that... you can determine what ratio ya have by markin prop shaft and flywheel.. with it in gear turn motor at flywheel 2 complete turns while ya monitor how many tha prop shaft turns.. one full turn on prop shaft it will be a 2 ta 1.. anything else its a 1.87 ta 1... clear as mud? think you will understand.

if you can get tha WH number of tha carburetor it will help with what it actually is..... decals/stickers/type cowls really don't tell ya tha whole story with these motors anymore............ gl.

 

[Faztbullet]

Looks like a 1994-96 Xr4 with old style cowl and early front air silencer

 

[scout-j-m]

6568786 is good number.. you have ta put a "0" in front of tha 6568786.. "06568786"... they added tha 0 to all existing and new serial numbers in '90/'91 i believe..... its a '84 2.0 150.. its has electrics from tha '89... mystery solved...
chris is close with his rendition of mercs.. they built one 2.0 200 and that was '79.. tha only 2.4 150's built are tha XR4 and an EFI.. tha only 2.5 150 was tha XR6 and an 150 EFI.. all tha other 150's with carbs were 2.0's...... all 135's are 2.0 motors..

look here for a build date... m/d/yr.. its on tha block kinda behind tha bend in tha timing arm.. may not be real easy ta see but its there....

Thanks so much! I'll check for that build date asap.

So from an electronics perspective, what all could I potentially swap over?

1. swap the stator from the newer motor to this older one as long as I also swapped the dual rect/regs?
2. swap the trigger?
3. swap out CDI boxes?
4. swap coils?

We will probably wait until after the holiday weekend to go give it another try but I plan on filling up a portable 6 gal tank full of fresh premix to run it off of and taking my DVA meter with me. Will see what the DVA numbers are and fiddle around with unplugging plug boots to see if I can isolate it to one side to see if I can trace it back to a single switchbox. Have yet to find any switchbox resistance specs. If I can't find the issue then, I'll dig into the carbs.

Just learning more about the motor through all of yalls help has given me a little more confidence I can figure it out eventually.

 

[Dukedog]

Thanks so much! I'll check for that build date asap.

So from an electronics perspective, what all could I potentially swap over?

1. swap the stator from the newer motor to this older one as long as I also swapped the dual rect/regs?
2. swap the trigger?
3. swap out CDI boxes?
4. swap coils?

right on all 4.....
triggers, switch boxes, coils are all pretty much same on all of 'em.. some different part numbers but thats about all.... if and/or when ya have a bad switch box its best ta change BOTH at tha same time......

We will probably wait until after the holiday weekend to go give it another try but I plan on filling up a portable 6 gal tank full of fresh premix to run it off of and taking my DVA meter with me. Will see what the DVA numbers are and fiddle around with unplugging plug boots to see if I can isolate it to one side to see if I can trace it back to a single switchbox. Have yet to find any switchbox resistance specs. If I can't find the issue then, I'll dig into the carbs.

Just learning more about the motor through all of yalls help has given me a little more confidence I can figure it out eventually.

while ya checkin' things "jus 'cause" run it after dark, ona hose is fine, move a screw driver ta ground around tha powerhead ta check for bad (leaky insulation) wires.. especially around tha coils and coil wires

 

[scout-j-m]

right on all 4.....
triggers, switch boxes, coils are all pretty much same on all of 'em.. some different part numbers but thats about all.... if and/or when ya have a bad switch box its best ta change BOTH at tha same time......


while ya checkin' things "jus 'cause" run it after dark, ona hose is fine, move a screw driver ta ground around tha powerhead ta check for bad (leaky insulation) wires.. especially around tha coils and coil wires

The nighttime check sounds like a good idea. I'll definitely give that a try.

Will probably be a while before we are able to go for another test run so may be a while before I update it but definitely will let yall know how it goes.