150 Mercury XR2 - fuel issue - leans out, won't start - now unidentified electrical component smoking

[Jtcarter21]

I have a 1985 Mercury 150 xr2 that has always had issues going wot, but after trying to woek on it last year its gotten worse.



First off though, there is a small box on top of the motor, behind the flywheel at the very back of the motor that started smoking later in the year. I thought it might be the rectifier, but it only had 2 posts, with a red wire and a dark yellow wire. What is this thing?



Next up, the fuel issue was improved when I cleaned all the carbs, next up I rebuilt the fuel pump and it just seemed to get worse from there. I took it to a shop and they told me the top carbs were doing good, but the bottoms were not putting ouy enough fuel. I bought the carburetor cleaning solvent to dip them, cleaned them again, and checked everything looked ok to me, I already did the rebuild kits with new gaskets, float pins/sits, etc.



In the middle of all this the head gasket failed. It was replaced , compression is good 115 ish on 5 cylinders but there isnsome scarring on top right cylimder wall from overheating, but compressiom was still 105-110. Its not worth rebuilding at this point, but I'd like to get some more life out of it if possible.


Thanks to everyone in advance for your help!

 

[boardhauler]

The small box may be your idle stabilizer. If it is, there should be 3 wires, black also for ground.

 

[Jtcarter21]

The small box may be your idle stabilizer. If it is, there should be 3 wires, black also for ground.

This is it, only 2 wires, haven't found anything about it on wiring diagrams, looks like the wires go to the rectifier.

 

[boardhauler]

Looks like a rectifier, but it must be something else. Hard to see from the pic. If there is a hole in it, it may be missing a post/terminal. Trace the wires and see where they go. Here is a complete elec. system for sale, that shows it.

https://www.ebay.com/itm/236736047059?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=236736047059&targetid=2450593697471&device=c&mktype=pla&googleloc=9011484&poi=&campaignid=21214286338&mkgroupid=186346748377&rlsatarget=aud-1339632007394:pla-2450593697471&abcId=9407521&merchantid=6577064&gad_source=1&gad_campaignid=21214286338&gbraid=0AAAAAD_QDh_tjwMnZBi4c9GKRGFLyy8U5&gclid=EAIaIQobChMI26TFzLedlAMVE1N_AB3WnRWWEAQYASABEgIg_fD_BwE

 

[Jtcarter21]

The

Looks like a rectifier, but it must be something else. Hard to see from the pic. If there is a hole in it, it may be missing a post/terminal. Trace the wires and see where they go. Here is a complete elec. system for sale, that shows it.

https://www.ebay.com/itm/236736047059?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=236736047059&targetid=2450593697471&device=c&mktype=pla&googleloc=9011484&poi=&campaignid=21214286338&mkgroupid=186346748377&rlsatarget=aud-1339632007394:pla-2450593697471&abcId=9407521&merchantid=6577064&gad_source=1&gad_campaignid=21214286338&gbraid=0AAAAAD_QDh_tjwMnZBi4c9GKRGFLyy8U5&gclid=EAIaIQobChMI26TFzLedlAMVE1N_AB3WnRWWEAQYASABEgIg_fD_BwE

There was never a 3rd wire, the top was solid before the hile formed, the two wires gonto what I think is the rectifier thats bolted in with the rest of the electrical connections.

 

[boardhauler]

I think you have a 2 part rectifier/regulator. The 2 terminal box is the voltage regulator. You can most likely replace it with a newer style all-in-one rectifier/regulator.

 

[Jtcarter21]

I think you have a 2 part rectifier/regulator. The 2 terminal box is the voltage regulator. You can most likely replace it with a newer style all-in-one rectifier/regulator.

That makes sense, kind of what I was expecting, drove the boat 20 miles today so whatever it is its not causing any real issues.