1985 merc 150 hp xr2 wiring and timing

JCraft

Recruit
Joined
Sep 12, 2013
Messages
1
Hi, I have done lots of research and have come to a conclusion of what repairs my motor needs to get it running, but I would like to first get some confirmation from the experts.

Serial Number A157368

It all started when I blew out the top two pistons in my engine. I had them bored and replaced them myself with new pistons and rings. I have the engine back together and have consistent 125psi in all cylinders. I also have spark in all cylinders and fuel getting to all cylinders. My engine still wont run. During the disassemble the 6 wires coming from the trigger were cut. I re connected them to what thought was how they went (when they were cut i thought they were 6 different colors, not 3 different colors for six wires. I am colorblind) and I believe I have them wrong and that is why my motor wont run. My theory is, I stripped all the housing back to the trigger and looking at the trigger it appears as if the six wires come out of the trigger in order. Am I correct to assume that these wires are in counterclockwise order of the firing order and i can trace each wire to make sure they go to the correct coil pack? From there I think it will surly need to be re timed because of everything that happened throughout the rebuild. I do not have the manual for it and cant get one anytime soon where I live. So doing static timing I believe at WOT it should be around 28 and because of being statically timed I dial it back to 26? Then I plan to remove the Spark Advance module from the recommendations of this forum.

Lastly the other module on the portside of the engine it has 3 wires (2 connect to the oil pump/mixer, 1 to ground) and I know where they go. It has another 2 wires that are blue and purple (no idea where they go) and then a green and red/purple wire that i dont understand where these go exactly either. I cant see in my pictures where they are before the disassemble and the colors (ive had inspected by someone who is not colorblind) do not match up to any wiring diagram that I have seen. Please help here too.

Thanks. Hope to have running to do the break in this weekend! thanks
 

Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,508
Re: 1985 merc 150 hp xr2 wiring and timing

Ya really need a wiring diagram. Maybe someone on here can send ya one or knows where on tha internet ta look. If tha trigger wires don't have "yellow" tape or a "yellow" sleeve on three of tha wires ya can leave me in tha truck. This identifies which three go to which switch box. They match up with tha coil wire harness with tha "yellow" identification. I'm sure there is some kinda "test" procedure ta identify these but triggers are cheap and I'm old..........Ya off a touch on tha timin'. Just ta start it I'd go ta "0" or 2* advance for idle You can set it ta run at 'bout 900 r's on tha hose then set it ta what tha motor wants when in gear, in tha water. Max can be anywhere from 18ta 22 degrees. Good comp and gas I'd go ta 20 ta 22 dry crankin'............
 
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