Yamaha alternators

96century

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Nov 23, 2004
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I have a 1996 SWS 175, how would I find out if my engine has an internal regulator or external, I'm going to install a guest isolator for my dual batteries with a 1,all 2 & off switch. This is one of the pre installation questions being asked of me, & I haven't a clue!! :rolleyes:
 

rodbolt

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Sep 1, 2003
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Re: Yamaha alternators

look at the rectifier. I belive it does. if the rectifier has 2 red leads and only one is used it has the built in isolator. post the the model number and I will try to hunt it down.
 

96century

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Re: Yamaha alternators

Ok, It's a 1996 Model name: S175TXRU 175 hp <br />Approved model # 65G Transom Hgt: UL<br />Serial # 500427<br /> X<br />Thats whats on the plate. <br />Thanks Rodbolt
 

96century

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Re: Yamaha alternators

More info on my research: I have a guest battery switch mod # 2101 with AFD (alternator field disconnect) & a guest isolator # 2401A for use with isolation diodes, I believe this is the isolator I need but I'm at loss when asked if my charging system (lighting coil) has isolation diodes or not!!! :confused: And then theres the actual swapping of wires around. I've found many schematics on the web but until I resolve this question I can't quite choose my situation! :rolleyes:
 

96century

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Re: Yamaha alternators

I found in my yamaha service manual # LIT-18616-01-41 that it shows my rectifier/regulator should have 4 groups of wires, but only 3 are identified (page 8-28)1=black 2=green 3=red <br />& 2 small leads that are not identified. on page 8-29 a different rect/reg is shown Hmmmnn!!<br />I have the oil injection version!<br />So in conclusion I now know I have an external rect/reg. But do I have isolation diodes? Because that determines whether I have the correct isolator or not? :confused:
 

Ray Neudecker

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Re: Yamaha alternators

If there is a seperate red lead with a fuse holder in the line, you should have the isolation diodes in the rectifier.
 

rodbolt

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Re: Yamaha alternators

hello<br /> the alt field dissonect is not applicable to yamaha outboards.<br /> if your motor has the seperate isolated lead a hull isolator is not nessasry for 2nd battery/house battery charging.<br /> why are you addng an isolator ?
 

96century

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Re: Yamaha alternators

Thanks Ray & Rodbolt for your research, but, what is the hull isolator you mention? Initially I was only going to add an on board charger to keep both batteries charged & at peak performance. But during my surfing on the web I learned that without an isolator I could possibly overcharge & cook the electrolyte right out of one of the batteries due to diferences in each battery. Thats where the isolator does its job, it allows the charge to go to the weakest batt first. It also provides a safety factor when offshore, by only allowing the batteries to drain individually vice as a total battery bank together. The charger is supposed to be electronically intelligent enough to provide a maintenace charge once both batteris are at or near 100%. So I'm still not clear on whether my engine charging system has isolation diodes or not, sorry if I'm not seeing the light!! :rolleyes:
 

chuckz

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Re: Yamaha alternators

To test for isolation diodes connect an ohmmeter (The Red Lead)from the alternator output AT THE ALTERNATOR to one of the battery positive terminal (The Black Ohmmeter lead) and check for continuity, swap the leads on the meter and see if you still have continuity. if yes, there are no isolation diodes, if no, there are isolation diodes.
 

96century

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Re: Yamaha alternators

Well I tried L.I. Chuck's procedure & did not have continuity when I swapped the leads, so I conclude my engine does have isolation diodes. I did it all in the engine compartment using the battery leads that came from the battery to a terminal block underneath the cowling, I assume that still accomplishes the same procedure? The rectifier/regulator on my engine has 3 green wires all connected & 2 red only, one being used the other is capped off. :) The red lead being used does have a fuse holder!
 

rodbolt

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Re: Yamaha alternators

el dorado<br /> L.I. is confused<br /> in most year model V6 yamahas since 97 or so, could be off a year or 2, the v6 motors had a 3 phase charging system with a battery isolator built into the regulator for charging a second"house" battery. by a battery isolator it means that both batterys can be charged by a single altenator but not drained by a common drain. IE the house battery cannopt be drained by cranking and the cranking battery cannot be drained by "house" useage.<br /> I am sorry I forgot to check today, had a pair of 270 crusaders eat me up. took me 3 hours to finally determine the reason why it was in for a tune up was cause it sank last week :) customer finally admitted it. took an extra 3 hours at 75 per hour to get it.<br /> if coming off your regulator there are 2 10 GA red wires and one terminates about 6" or so from the regulator and is not connected you have the 3 phase isolated lead regulator. if only one red lead going to the solinoid you dont.<br /> so the capped red lead take to the second battery. by USCG regulations the battery negative posts must me joined by a wire no smaller than the engine starting cables.<br />and fuse that capped red lead your going to use with the same size and type of fuse in the one being used
 

96century

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Re: Yamaha alternators

Thanks for looking in on my project Rodbolt, but let me see if I've got this straight. So it sounds like I indeed do have the 3 phase lighting coil rectifier/regulator (alternator) because I do have 2 red leads one that goes to a fuse holder that is being used & the other, like you say is a 6" pigtail that's capped off & not being used at this moment. Presently the way the boat & engine came and are wired is: OEM wiring to a 4 position (off, #1, #2 & both) Guest battery switch, the positive lead from the engine cowling connects to the feed terminal on the battery switch, the negative lead from the engine goes directly to the neg post on to my starting battery which is has another lead of the same gage joining both negative posts. The positive leads from each individual battery go to the #1 & #2 battery switch terminals respectively. I assume the engine output charge for the batteries is through that positive lead!! :rolleyes: :confused: <br />Would you suggest I remove the battery switch & run a lead from the 2nd red lead on the rect/reg to the 2nd battery? If I did this scenario how would I use the 2nd battery for starting if I needed it?? :confused:
 

bigbrownbuku

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Sep 17, 2004
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Re: Yamaha alternators

there are a few ways el dorado.<br />you can add a second on/off switch that connects the "house" battery to the start battery. i have seen some that use a switch at the dash connected to a solenoid to do the same thing, ie hold the "emergency cross connect" switch in to start the engine with the house battey. usually a momentary on/off so its not forgotten and left conected.
 

rodbolt

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Re: Yamaha alternators

hello<br /> I have seen it wired into the second(house battery at the #2 switch terminal. I prefer to wire it through a second switch to the #2 terminal so when both switches are off all power to the engine is secured.
 

chuckz

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Re: Yamaha alternators

Rodbolt,<br /><br />What I told El Dorado was correct. He proved he had a diode in line between the alternator and battery.<br /><br />BUT I gave him generic information. Without seeing the set-up I would not have known that the isolator was part of the regulator and the lead was there for the second battery.<br /><br />I would not wire as BenC suggested because you would be dividing the charged battery output between the starter and the dead battery. I would use a Perko battery switch so I could select either battery 1, 2 or off.
 
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