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Voltage regulator on MCM170 problems

rtscardina

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"Hi ALL,

I recently had a s


"Hi ALL,

I recently had a situation with my voltage regulator smoking and burning a black (what appears to be ground wire) from the regulator itself. The regulator is a water cooled regulator.
Can anyone tell me why a voltage regulator fails and what if anything i should be looking for before I replace it??
As it stands I cant find the exact replacement as I think the model numbers have changed, or anything less than 400 dollars..so i dont want to waste money to only have the problem return.

The part number off the regulator is a 99502A 11?? I have searched online and can only find 99502A 12 or 13... any help on this as well??



Thanks!!"
 
the dash 12 or thirteen is no

the dash 12 or thirteen is no more than a newer rev for the same part.

The regulator is a diode brige rectifier that converts the AC voltage from the stator to DC volts to charge the battery.

This is a very expensive system to replace ( stator and regulator) it is only used on this merc engine!! and you may want to look on ebay for a one wire altenator conversion kit and be done with it for ever. The kits is a bit pricy at around $500+ but it will be a one time expense.

Kghost
 
Thanks for the input! But I am

Thanks for the input! But I am still curious what causes the failure. Any idea what to look for? Ohming? Grounding?..

Also your recomendation of adding the single wire alternator kit is interesting but after I viewd the online instructions it appeared very invloved and requires a bit of room which the sea ray doesnt really have in the dog house.
 
"It is a the nature of the dev

"It is a the nature of the device. It could be a diode failure, it could be the inability to get rid of the heat from the unit due to poor water flow or restricted water flow, could be a couple of different reasons.

It is what it is. You could check out the stator output I believe the 2 yellow wires that feed the regulator. check the resistance between the wires and each one to ground.

I do not have the proceedures/schematics at my disposal at the current time."
 
Solid state elec. devices don&

Solid state elec. devices don't like heat which is created by elec. current; thus water cooled regulator. Merc. created this overpriced dog out of an outboard system that doesn't require the current draw of an I/O setup therefore the pricey regulator.

Someone was on this site in June/July w/a bracket kit he makes and sells. I suggest that you sincerely try to make the single wire marine alternator work for about $250 rather than pay $400+ for a new regulator. Use the SEARCH above to find it.
 
"My 470 W/C v reg went out sev

"My 470 W/C v reg went out several years ago, possibly due to running the motor a few minutes without knowing the water pump impeller was shot so the reg overheated. Long story short, I bought a new marine rated alternator at the local auto electric shop for $105, fabbed the mounting hdw in a few minutes, mounted it and installed a belt to the existing pulley on the damper, taped the two yellow wires (separatley) from the old alt and have enjoyed trouble-free boating since. I highly recommend that course, IF you can squeeze it in your doghouse. I moved the overflow jug and used that spot for the new alt. About 1/8" between the output terminal and the motor valve cover. One wire hookup. I also installed a low water pressure switch alarm so I know the water pump is working. Got me once, not again! JW in Dixie"
 
Great advice by all! Thanks!

Great advice by all! Thanks!

It stinks that the part is so expensive but I heard the alternative is also less costly in the long run.

I am seriously considering the alternator kit but I am curious about balancing the new pulley. Is that something that is done easily? I have heard if they are not mounted exactly right that the wobble could put a lot of tension on the belt and pull the alternator off the motor.

One last thing.. great point about the water temp and pump. My guages didnt show any crazy temps. It pretty much runs at 120-125 degrees consistantly. I'll be sure to watch that closely.
 
Rich

You have a problem wi


Rich

You have a problem with your temps!!

Either your gage is bad or your sending unit is bad or bad ground or you have the wrong thermostat in the motor.

The closed cooling motors ( 170 470 what ever else the numbers are) the one of a kind merc 4 cyclinder engines run a 160' thermostat. You should be seeing temps under normal running condition at 160 to 180 degrees.

You may want to look into this. The sending unit when heated changes its resistance. If I remember correctly it goes from ~ 60-80 ohms to ~ 240 ohms.
I dont remember which reading is a hot one or the cold one. Pull it out of the motor and test cold and record the ohms.
Heat up some water in a pan on the stove and try to get it to 180-190 degrees and try keeping the meter leads on the sending unit ( red to stud and black to body) dip the base of the sending unit into the water and watch your meter. If is a smooth increase/decrease then the sending unit is good. If it jumps a large amount or does not change very much then the sending unit is bad.
 
Than you! I am on it!..unless

Than you! I am on it!..unless of course I read my guage wrong!.. Ill verify with the procedure mentioned...Ill be back!!
 
"If I can attach a picture her

"If I can attach a picture here, it is of the belt-driven marine alternator I installed on my MC470 when the water-cooled voltage regulator bit the dust and I found out what a new one cost$. I made the mounting bracket from a piece of 1/4" x 1" flat bar, bending to shape. It is mounted to the cylinder head where the overflow bottle was. Move it to port. Easy rig since there is a spare belt sheave on the damper anyway. Alt cost $105 from the local auto electric shop. I yr warranty. Have run this about three years with no problem. I have a couple of other pictures - you can email me. JW in Dixie"
 
Kghost... I checked my guages

Kghost... I checked my guages again and realized I made an error.The boat runs at the hash just before the 175 indicator..I assume it to be 160 or so.

Warren...I was wondering why a sheave existed on the damper. I was scratching my head thinking why cant I use that?..I guess you can!

I have a 170 and it appears it is almost Identical in configuration. I would appreciate some more photos to guage where you mounted your hardware. Also you mentioned bending some metal to fit the application. Can you give me some ideas orpointers on that?
 
"Rich, my other photos are too

"Rich, my other photos are too large to attach here so I will email them to you. I have a large vice and a cutting torch, so bending the 1/4" x !" flat bar is a cinch. Maybe you can see in the picture. It's just flat where it mounts to the two holes in the head, then turned 90 degrees toward the bow for the length of the alternator, then to the starboard for a few inches to provide a mount for the belt tightener, a separate piece of bar. Hope you can see in the pix. Yep, I used the existing belt pulley. Good luck. JW in Dixie"
 
Thanks for all the help!! I n

Thanks for all the help!! I need one last thing!

Does anyone know what the OLD charging system for a 170 put out ?
I am trying to get the correct alternator for to his mock up.
I have a 50 AMP circuit breaker on my engine harness...does this mean I need to stay below that??.. or are the two not related?
 
The circuit breaker limits the

The circuit breaker limits the current drawn from the battery thru the electrical system except for the starter. A marine 60-65 amp alternator will be sufficient for your boat. The alternator output is fed to the battery w/a tie in at the starter.
 
"I want to thank everyone who

"I want to thank everyone who helped me through this votage regulator deal.
Update! I purchesd a marine alternator, some wire and fashiloned some pieces of 1/4 aluminum L brackets to support the alternator. I grabbed some 7/16 SS threaded rod to make the swivel point and lastly a piece of slotted steel for the tension adjustment. Slight modification to the doghouse was needed due to space constraints.

All in all I spent 150 dollars and some sweat equity. The system is chrging beautifully now and from what i gather should be trouble free for a while.

Thanks to all that assisted. I couldn't have done it without your support and knowledge!

Have a safe summer on the water!"
 
I also have a 470 with the &#3

I also have a 470 with the "smoked regulator" option. I used to use a solar charger but this year I fabricated my own mount and installed a gm alternator that I had from a car. Cost...$0. Also know that the temp guage did not read correct at the 10 or so volts without a charging system.
 
""installed a gm alternato

""installed a gm alternator that I had from a car"

IT'S NOT COAST GUARD APPROVED BECAUSE IT DOESN'T HAVE SPARK ARRESTOR SCREENS ON IT.
stop.gif
IT'S A SOURCE OF FIRE. GET A MARINE ALTERNATOR!"
 
"Yes Guy, That is in the plan.

"Yes Guy, That is in the plan. I went to buy one before my trip and they were out of stock. Had to use car one in a pinch til the correct one arrives."
 
"I've heard if you have po

"I've heard if you have power assisted steering that an alternator conversion is not an option, any truth to that?"
 
"David, I don't have power

"David, I don't have power steering so can't answer, but I suppose they put the pump where you would put the alt. Maybe you could offset the alt if there is room in the doghouse. Anything can be done if you crank it fast enough! JW in Dixie"
 
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