Bad regulator

[Sirrobin53]

I have a rough idle and pop/backfire on the pipe. I have been reading a lot of forums and they have led me to believe that the regulator /rectifier is the culprit. Burned yellow leads on the regulator and at the bayonet connection that goes under the flywheel, along with no charging and eratic tachometer. I would like to know what voltage the 2 yellow wires from the stator are supposed to be. I assume that the regulator is bad by no output. I have 18v between the 2 leads from the stator. Thanks in advance.

 

[GA_Boater]

What Merc are you working on?

 

[Sirrobin53]

Sorry. 2005 Mercury 75 horse 3 cylinder serial number is B 065874. I forgot to put Merry Christmas on my last post. Good to see you GA_Boater

 

[Sirrobin53]

The output on the stator is 15 volts at idle and goes as high as 36 volts. the tachometer isn't functioning so I have no idea what the RPM is When I raise it up to achieve that 36 volts. It is also hard to come off idle very far because it pops through the exhaust so severely.

 

[Chris1956]

I doubt a bad VR would affect the ign in the way you describe. Is this motor new to you? If so, I suspect ign timing is set wrong. Backfire thru exhaust is usually timing set too late. Is the trigger under the flywheel moving as the throttle is advanced?

Stator voltage on yellow wires should be AC. Is that what you see? If so, I suspect the tach is bad or the wiring to the tach is bad.

BTW the VR looks to be bad as well.

 

[Sirrobin53]

Yes. AC voltage. Mercury 90hp ELPTO 2 stroke (idle sputter) - www.ifish.net
https://www.ifish.net/board/showthread.php?t=446003
I hope that this is ok. This is where the regulator fixed an idle problem with the symptoms that I have when on the pipe. They describe the regulator and burned connections like I have. The video is exactly what I am having.
. Yes the motor is new to me. My first Black motor. Though the link and sync is similar to the other brand that I am most familiar with. I have been looking for the voltage that the stator is supposed to deliver but not finding much. As previous post, I have about 15 volts at idle and was able to get it to 36 volts by fast idle. Quite a chore because of the popping. If I had to guess the highest RPM to get the 36 volts it would be around 2300, 2500.

 

[Faztbullet]

Don't be racing motor on a hose !!!!

 

[Sirrobin53]

Does the regulator need to be hard wired in so the overheating of connections is eliminated?

 

[Sirrobin53]

I see J Martin posts of dual rec / reg on some of the v6 mercs and find some similarities of symptoms between the two. Looks as though the dual setup is for more amp capacity. The 75/90 motors share the same block. Do both motors output the same amps?

 

[Sirrobin53]

Anyway, I have ordered a reg/rec. The bayonet connections have been melted at both the flywheel and the rec/reg. Output of the rec/reg remains the same as the battery voltage, ie, as in no change of voltage regardless of RPM. For now, I am going with the stator being functional based on 15v AC at idle and raising upward of 35v as speed increases. The tachometer not functioning further strengthens the rec/reg being at fault.

Thanks for the responses so far and I appreciate the knowledge and know how. I have been able to work through many troubleshooting sequences with the help of all the responses to my questions on this forum.
Merry Christmas.:usa2:

 

[Chris1956]

I would recommend an OEN service Manual. You need to check the link and synch of that motor.

Bad rectifiers can affect spark, but do not change timing, at least not in my experience.

 

[Sirrobin53]

Had a day above 60° so I ran new wires from the stator to the old rec/reg. No difference in the voltage reading. Was hoping for better result. Maybe bad connection, but alas, no joy. Still waiting for the new one......stay tuned.

 

[Sirrobin53]

Tracking the part with fingers crossed.

 

[Sirrobin53]

I noticed that when the motor is cold that it will do a lean sneeze. When it does, exhaust smoke leaks from under the flywheel. Bad seal? How hard to change it? Would that suggest that the lower is also suspect ?

 

[racerone]

There is no " exhaust " near the top crankshaft seal.-----Have you looked at the " oil recirculation " hose on this motor ???-----Post the values of a compression test on this motor.-----That may or may not give clues on issues with the " lean sneezing " on this motor !

 

[Sirrobin53]

This appears to be in spec. Exhaust doesn't come out under flywheel? Seriously, I wondered what the smoke was too. How involved is changing the top crank seal? pull flywheel then seal? Honestly, it smokes from under the flywheel. My next start cycle I'll get it on video.
The new rec/reg made no difference. Still pops through the exhaust and no tachometer function. It was a 5 wire. I removed a 6 wire. I have a 6 wire on order now. The first one was missing a black wire that i assumed was a ground. The replacement has that black wire.

 

[racerone]

If you have " exhaust smoke " coming from under the flywheel you have serious engine problems.----Have you looked at the oil recirculation line , yes , no or do not understand what that line is ?

 

[Sirrobin53]

Port or starboard side of the crankcase?

 

[Sirrobin53]

Do you put a little grease on the shaft when reinstalling the flywheel? I pulled the flywheel because I suspected a bad seal on top of the crank. Here's what I found.

 

[Sirrobin53]

So the end result was the trigger being stuck to the top of the housing. Now it turns freely and advances properly. Pretty hard to see with just one guy. I was able to scrape the inside of the trigger out so that it had just enough play that it could twist without binding and adjust the timing properly. And it was blatantly obvious that there was a crankshaft seal problem on the top once I got the flywheel off. That's why I was asking the question how can they smoke from under the flywheel. Well obviously they can. Must Must happen pretty routinely because my friendly neighborhood Mercury dealer has plenty of them in stock. Headed to the lake this weekend. The walleyes are biting on Dale Hollow.