Problem with startup on '97 mercruiser 454

[petryshyn]

Re: Problem with startup on '97 mercruiser 454

Hi clanton<br /><br />1000 rpm is normal for a one wire alternator. That alt relies on residual magnetism to start charging and requires higher rpm the longer it sits. Thats why the three wire alt is far superior.(more wires to connect, but worth it) Its energized by the ign switch, and has an external sense line which is superior for voltage regulation.<br />>if 1000 rpm cut-in bugs you.....I can show a modification to have it cut in earlier..Or, we can easily convert it to a 3-wire.<br />

 

[ODDD1]

Re: Problem with startup on '97 mercruiser 454

schematic, whats your prob with mando alternators?? Yes, korean made, yes overrated, but have been used on mercruisers as original equip for years....and I have pulled off more delcos for replacement than mandos....the delcos dont seem to be as tolerant of abuse [dunking,running with no battery in curcuit,dead shorts,etc,etc]...granted, the single wire is a nice package for a rework/custom install, but the 3 wire doesn't have anything on the mando with the exception of higher available outputs. my experience has been the the higher you push the output in a given frame, the faster durability drops....by the way, now merc sends you a leece-neville as a replacement for the single wire, 3 wire and the mando....is a prestolite with a diff name on it.....and a 3 wire to boot.

 

[petryshyn]

Re: Problem with startup on '97 mercruiser 454

Hello ODDD1:<br /><br />You know the old saying....go with what you know....LOL<br />>you say its only capable of 35 amps<br />>you say high speed cut-in is normal<br />>I trust what you say, cause I've never seen a mando. (unless its a prestolite in disguise)<br /><br />In my opinion, delco and nippendenso rule, leece neville and prestolite are 'as one', and run a close second, and motorola....hmmm. But thats in my enviroment......I wouldn't know where to place mando.<br /><br />>The suggestion I have is to lose the mando (if possible) acquire a 10si delco three wire from a wreckers($10-$15) buy the screen kit for $15. Now you got a delco marine for $30.00. <br />>Three wire is still the best bar none. One wire is more convenient, but has issues. One wire systems are the ideal choice on engines without ignition switchs (eg. some diesels)<br /><br />>With the addition of a 27si long life brush set($3.00), the 10si remains America's most versatile, cost effective, adaptable and user friendly alternator ever made. Yeah, I might be a little biased(worked for GM) but I assure you.........I repaired just as many or even more other brands.<br /><br />>Yes there was a open circuit issue early in there history. There also was a severed sense line issue that caused concern. An upgraded regulator addressed those problems years ago.<br /><br />>With CS, I think we have more problems here than meets the eye. 2000 rpm is too high a cut-in speed for a multi-wire system. I don't like the idea that the alt will only put out 35 amp. That in itself can lead to a short life. I'm curious to see if the cut-in speed will reduce if the stator load is reduced by removing the choke lead. If so, we can work around that.<br /><br />******************************************<br />In a nutshell...........<br />>if CS can live with reving up a cold engine to start the charging process.......<br />>if CS keeps accessories to a bare minimum...<br />>if CS doesn't use a trolling motor or additional batteries..........<br /> <br />Then live with the Mando.....<br /> <br />But if he wants more out of his boat, I'll be here to help........<br />

 

[cschauerj]

Re: Problem with startup on '97 mercruiser 454

Wow, where do I start! I feel like I've been initiated here. Thanks for the insight fellas. Schematic, I took some voltage readings today. Key on, engine off: The "S" wire coming from the regulator =12volts, the "EXE" wire from the reg. =12volts, the power wire reads 12volts and the wire also connected to the voltage regulator that travels to the electric choke reads 2volts DC, 4volts AC. Other than that there is a ground wire. The alternator seemed to generate voltage a little lower on the tach today(maybe 1500rpm), maybe that's more acceptable. Either way the choke didn't seem to open fast enought to prevent the motor from flooding even with the extra juice flowing to it. I wonder if it was somehow damaged by proping it open as a temporary fix. Although, if that was the case, I would think it would have a tendency to stay open rather that closed. Walter, you are more than likely correct. When there wasn't problem with the boat, I wasn't exactly studying the gauges as I am now. It's very likely that I just didn't notice the characteristics of the alternator. Thanks for the insight on the Mando alt. ODDD1. Makes me think I'm just too paranoid at this point in the game. As far as Schematic's philosophy on go with what you know, I agree. And I don't know jack about alternators other than I've never had to replace one in a car. And... I know inexpensive too. Unfortunately I don't have the option of returning the Mando once it's been installed and IF IT'S OPERATING PROPERLY. The flame arrestor kit for the Delco is a great fix that I will keep in mind in the future. Unfortunately, as in this case, my impatients sometimes gets the best of me and instead of loosing time on the water to search a salvage yard I buy new and have it delivered to my door instead. So... in a nutshell, I won't be using too many accessories, trolling motors etc. I suspect there is a problem with the electric choke now. I don't care for it enough to replace it so I'll bypass it. So I won't need to rev the cold engine to start the alternator. That will happen once the engine is warmed up and I'm on my way. So I guess i'm living with the mando. Wish me luck.

 

[petryshyn]

Re: Problem with startup on '97 mercruiser 454

CS<br /><br />>engine starts good but idles poorly after 5-10 sec. = vacuum break problem<br /><br />>engines starts OK, runs OK but doesn't come off of fast idle for a long time = heated choke problem.<br /><br />Go with the mando if you can't return it.<br />If ODDD1 says there OK, I believe him.<br />Not worth the hassle to achieve perfection if mando will do....LOL<br /><br />Live long and prosper!!!

 

[Hooty]

Re: Problem with startup on '97 mercruiser 454

Whew!!!<br />This made me tired---but it sure was informative.<br /><br />c/6<br /><br />hooty

 

[cschauerj]

Re: Problem with startup on '97 mercruiser 454

Thanks Schematic and Co. Post you back when the next disaster strikes. This site rules!

 

[ODDD1]

Re: Problem with startup on '97 mercruiser 454

schematic...as a side note, have you ever started a mercruiser EFI engine? notice how the motor 'flares' rpm up to about 1500 with the throttle closed? wonder why?.... you betcha...giving the charging system a kick in the pants....we all know how puters hate low voltage......the mando is a knock off of the motorola, one of the poorer units mcm used...made me shake my head in shame, when I saw the koreans makin them better....

 

[petryshyn]

Re: Problem with startup on '97 mercruiser 454

Hi ODDD1!!<br /><br />If you ever run across a schematic of the internal electronics of a mando, I'd sure appreciate a look at it. I find it interesting that any manufacturer's design would lend itself to a high cut-in speed alt. I've seen computerized circuits designed to address that very problem in single wire alternators. There is no reason to have this deficiency in a 3 wire system. Would love to design a retrofit that would rectify this mando trait! As for the 'flare' in rpm at start up.....thats a whooooole different topic........<br /><br />thanks man...

 

[12Footer]

Re: Problem with startup on '97 mercruiser 454

WOW!! I agree with Hooty! What an education I just got!<br />I like the Leese Nevil setups, because that's what they use on police cars,fire trucks and fire boats. They seem buletproof.<br />I learned that from the garage at the city I werk for. I used to be heavy into ham radio, and needed 80AMPS,continuous-duty power for my mobile radio gear. I had to run a seperate alt and battery package. But I still had problems with the high spurious RF killing the computer in the truck. But the power supply was rugged.

 

[petryshyn]

Re: Problem with startup on '97 mercruiser 454

Hi 12footer:<br />Leece Neville 'JB' series were very rugged. Being able to change brushes and reg. on these units without removing them from engine, always appealed to me. As far as your RFI problem goes....having the battery as close to the alt. as physically possible,(charge lead acts as an antenna) ground strap from hood to body, ground strap from end of exhaust pipe to body, choke(inductor) installed inline of the computer power supply, and condenser across alt. output took care of most radio noise I've run into.... The neat thing about L.Neville is that they were under-rated.(a 120amp would put out 150amp etc.) The bad thing about this is, if a diode failed, the output would still fall around the rated spec. If you didn't actually view the output on a lab scope, you'd have no way of knowing about the diode failure. This resulted in RF interference.(common)