1989 Mercury Black Max 150 - problems with power, missing on cylinders

**Dave Strong** · 06-25-2015, 08:53 PM

What year and serial number do you have? Good chance I have the real Merc manual and can send you the procedure.

Dave

**tlwjkw** · 06-26-2015, 04:45 AM

try this one....

**trevstar** · 06-26-2015, 06:06 AM

Thanks Dave and tlw.
It's a 1989 - 0B313046

**trickcraft** · 06-26-2015, 10:17 AM

Dave that link and sync procedure would be great. Also trying to figure out my motor which came on the cougar i bought in the fall. Serial number a179156. Its an 85 200HP Black max. It seems to have the xr2 advance on it. I had water in cylinder one which new gaskets have seem to have solved. It does not want to idle nor run well. I have only started it on the trailer in neutral. I have not really rested it under load yet. but will try this weekend...

**tlwjkw** · 06-26-2015, 11:45 AM

get rid of any and all idle and/or advance modules... linc n sync is generic on any of tha ones that have been discussed including your 200....both motors set idle timing/rpm with tha "10/32 screw only" with tha boat in tha water in gear ta whatever makes both of ya happy... set max at 22 crankin' with all tha plugs pulled....if ya can't make it idle with that screw only, ya got carb/fuel delivery or 'lectric problems...

**trevstar** · 06-26-2015, 03:50 PM

Hi tlw,
Thanks for the document, but i don't see anything in there about "link and sync" and nothing about timing. It's all geared toward the electrical side of the motor. Is that the document you meant to post, or am I somehow missing the section I'm supposed to be looking at?

Thanks.

**tlwjkw** · 06-26-2015, 04:34 PM

sorry, wrong one.... I will dig a little more..

**TEXAS20225** · 06-26-2015, 06:33 PM

keep that document Tommy posted it ends all the 12oz curl guys( specially when they done had one too many) "storys" on what came on what as far as efi, i printed this out about four years ago and have used it dozens of time

. IM CURIOUS WHATS A XR2 ADVANCE its a 150 i know, but all these motors advance via trigger when mota is throttled up

**Dave Strong** · 06-26-2015, 07:44 PM

Originally Posted by TEXAS20225

keep that document Tommy posted it ends all the 12oz curl guys( specially when they done had one too many) "storys" on what came on what as far as efi, i printed this out about four years ago and have used it dozens of time

. IM CURIOUS WHATS A XR2 ADVANCE its a 150 i know, but all these motors advance via trigger when mota is throttled up

He might mean the XR4 module that advances over 5200 like 6deg then once it hits 5800 it take a few deg out.That module caused alot of issues. Not sure of the rpm and amount of advance or retard. But Merc couldn't make a module that did one thing good, don'tknow why they thought the could make one that did 3 things work.

Dave

**trevstar** · 06-29-2015, 06:54 AM

Hi all,
This weekend, we went through the timing and synchronization chapter of the Seloc manual. I assume it has similar goals to the Mercury Link and Sync??
We reset the timing, and put all the carburetor linkage back to the settings per the manual.
The motor idles better due to the adjustments, but the miss is still readily apparent on take-off. It misses all the way up until it's on plane and at WOT, then it disappears. If I back off the throttle down to about 3000 RPM and punch it, it seems to hit on all 6 and accelerates quickly back up to top speed. So, I guess, the best way to describe it is that under load it has a miss.
I was able to build a DVA after ordering parts from Digi-Key, and it helped us to get the readings I've struggled to get.
The spark plugs all were hitting the 40kv gap after the timing adjustments.
The idle stabilizer remained removed.
We tested the voltage regulator and it tested out ok. All impedance was good, and it produced anywhere from 12.5V - 13.5V when running between idle and about 2000RPM.

All these readings were taken at idle.
Port side:
Blue/Wht - 320V
Red/Wht - 100V
Grn/Red - 235V at switch, 209 at coil
Grn/Wht - 235V at switch, 200 at coil
Grn - 245V at switch, 210 at coil

Starboard:
Blue - 325V
Red - 95V
Grn/Red - 240V at switch, 225 at coil
Grn/Wht - 240V at switch, 225 at coil
Grn - 245V at switch, 220 at coil

I read some stuff about bleed lines causing problems. Is there any chance that bad check valves could be causing my issues?
I checked into carburetor gaskets and nobody in 50 miles carries them. I'll have to order them. Would I be better off to order rebuild kits and just rebuild them all, or is this just throwing money at the problem still?

Thanks,
Trevor

**Dave Strong** · 06-29-2015, 03:42 PM

Click image for larger version.

Name: 150-200 link and sync pre 90.pdf
Views: 170
Size: 3.93 MB
ID: 322568

Link and sync from Merc manual for those that wanted it. Do Not do as they say to adj. idle speed. Once you have the throttle cam and carbs sync done Do Not adj. idle speed with the throttle stop screw use the pick up timing to fine tune idle. Using the idle stop screw to increase idle speed will open the throttle plates at idle and you Don't want that because then the carbs are no longer on the idle circuit and will idle like crap.
PS you missing still sounds electrical not carb to me. but I am not there to hear, feel it run. There are times when all checks ok with the right tools and still have a bad part.

Dave

**trevstar** · 06-29-2015, 07:09 PM

Thanks for posting that Dave. The Seloc manual seems to be a bit of a copy/paste, but there are some notable differences. I'll go through it step by step tomorrow with your exceptions and let you know how I make out.
I will also take some video of the boat running on the lake so you can see and hear what it's doing.

**trickcraft** · 07-01-2015, 01:32 PM

Trevstar, I am no expert and as noted have similar issues to you. I also pulled and cleaned my carbs and looked in to see the reeds noting no major issues. Took a closer look and pulled them. See attached. It was well worth the process as many of the issues I could not see when looking through the plenum.

Click image for larger version.

Name: IMAG0976.jpg
Views: 108
Size: 286.6 KB
ID: 322678

Click image for larger version.

Name: IMAG0977.jpg
Views: 74
Size: 313.4 KB
ID: 322679

Click image for larger version.

Name: IMAG0978.jpg
Views: 98
Size: 315.8 KB
ID: 322680

Can someone recommend replacements?. Again its a 1985 merc 200 black max.

**Dave Strong** · 07-01-2015, 02:02 PM

Originally Posted by trickcraft

Trevstar, I am no expert and as noted have similar issues to you. I also pulled and cleaned my carbs and looked in to see the reeds noting no major issues. Took a closer look and pulled them. See attached. It was well worth the process as many of the issues I could not see when looking through the plenum.

Can someone recommend replacements?. Again its a 1985 merc 200 black max.

Whos ever reeds you chose you need to lap the sealing surface smooth and flat before you install new reeds. Does not look like it was done on those.

Dave

**trevstar** · 07-01-2015, 05:00 PM

Thanks for the post, trick. I may tackle that when I get back to the cottage again. I need to get some gaskets ordered before I can tackle anything in the fuel system again.

Dave, we had the heavens open up yesterday and I wasn't able to get anything done on the boat. I'll get that video for you asap, and do the link and sync. Also, we were talking about testing all the cylinders to make sure that the new trigger that was installed last year is firing the right coils in the right order. (fyi, to me it doesn't sound like it's mis-firing, just, not firing at all.) Is there any concern that the power packs are receiving higher than expected voltage (320V / 100V) from the stator, or is that fairly normal?

It might be a few days before I can get back to check it all out, but I will do so as soon as I can.

Trevor