150 Mercury Black Max problem!!

[jthorne76]

I just purchased a used boat with a 1992 Mercury 150hp black max, the motor will run but only with the cover off, the previous owner advised me of this, and showed me what he believed was causing this, there is a quarter size hole on both sides of the crankcase cover, which I'm sure isn't good, the holes appear to have been "blown" out from the inside, I did confirm the motor will start and sounds like it is running normal, I will refrain from starting it anymore until I find out the extent of damage, has anyone seen this before or does anyone know what might have caused this. Thanks and God bless.

 

[RLT III]

Re: 150 Mercury Black Max problem!!

post a pic so we can see what you talking about

 

[j_martin]

Re: 150 Mercury Black Max problem!!

You got yer hands on one of Mercury's top secret ventilated crankcase racing engines. Another key component of that engine is the Z-rod.

 

[j_martin]

Re: 150 Mercury Black Max problem!!

No more advice for this guy?

 

[sschefer]

Re: 150 Mercury Black Max problem!!

No more advice for this guy?

I love ya man....

Seriously though... The problem you're seeing is serious... That's a no s.....ter. You gotta tear it down. It definitely aint runnin on all 6 and never will like you describe.

 

[rikoshaprl]

Re: 150 Mercury Black Max problem!!

I am not a mechanic but have had that Mercury for ten years, I think you must be running on only 5 cylinders. The sixth blew out. You can check it by removing one spark plug wire at a time while the engine is running (wear good gloves so you don't get shocked), You should hear the engine stumble when you remove each wire. If one of the wires you remove doesn't make the engine stumble it is because that cylinder is shot. The location of that cylinder will probably coincide with the hole in your cover.Then you know for sure you need engine work.

 

[sschefer]

Re: 150 Mercury Black Max problem!!

I am not a mechanic but have had that Mercury for ten years, I think you must be running on only 5 cylinders. The sixth blew out. You can check it by removing one spark plug wire at a time while the engine is running (wear good gloves so you don't get shocked), You should hear the engine stumble when you remove each wire. If one of the wires you remove doesn't make the engine stumble it is because that cylinder is shot. The location of that cylinder will probably coincide with the hole in your cover.Then you know for sure you need engine work.

Maybe you should rephrase that to "this will ensure you'll need engine work".

Quarter sized blow outs indicate a serious engine problem. If you're unsure of your diagnosis then here's a pic of what a good one looks like:

 

[saumon]

Re: 150 Mercury Black Max problem!!

Hey, nice to see Frank again! sschefer, where are you located? That ?pompe de puisard? box tickle me, as i'm french speaking. Were you near the Quebec border?

 

[sschefer]

Re: 150 Mercury Black Max problem!!

Hey, nice to see Frank again! sschefer, where are you located? That ?pompe de puisard? box tickle me, as i'm french speaking. Were you near the Quebec border?

I'm in Northern California about 50 mi north of San Francisco. I'm pretty close to Home Depot.. The pump was made in Canada. Nice one too. Ran all winter almost non-stop at times and kept my backyard from flooding.

Re Frank, the block is finally getting bored. I waited too long and the shop is backed up with spring time PWC and ATV work. Frank isn't on the schedule until May 1st. No biggie, it's a project motor so it's not like I need it tomorrow or even next year.

 

[saumon]

Re: 150 Mercury Black Max problem!!

I'm in Northern California about 50 mi north of San Francisco.

It's a bit out of my neighborhood!

 

[jthorne76]

Re: 150 Mercury Black Max problem!!

well....................got a broken connecting rod, looks like a rebuild for me yippy!!!!!!!

 

[sschefer]

Re: 150 Mercury Black Max problem!!

well....................got a broken connecting rod, looks like a rebuild for me yippy!!!!!!!

Sort of figured that.. But hey, now you'll get to learn all sorts of cool tricks you can do to make it even better than new!

 

[mmeissner420]

Re: 150 Mercury Black Max problem!!

I have a 1992 mercury black max 150 hp on my 1992 checkmate spectra. The motor runs great when im running it all out. After I put around the lake for a few minutes then try to take off it boggs out really bad and in some cases when im trying to pull up a skiier, i end up dragging the poor person around the lake. Ive tried changing plugs, did a compression test(everything matched up to specifications). Not sure what i can check for to fix this. Any input would be great. I really really need to get this fixed soon. Its been too long. Need the kitten to be purring again, Any suggestions would be greatly appreciated. Thanks

 

[sschefer]

Re: 150 Mercury Black Max problem!!

I have a 1992 mercury black max 150 hp on my 1992 checkmate spectra. The motor runs great when im running it all out. After I put around the lake for a few minutes then try to take off it boggs out really bad and in some cases when im trying to pull up a skiier, i end up dragging the poor person around the lake. Ive tried changing plugs, did a compression test(everything matched up to specifications). Not sure what i can check for to fix this. Any input would be great. I really really need to get this fixed soon. Its been too long. Need the kitten to be purring again, Any suggestions would be greatly appreciated. Thanks

Try starting a new post with this same question. You'll probably get a quicker response.