mercruiser 470 alternator conversion no start wiring question

[olazabel]

I have a 1978 mercruiser 470, just went with a 1-wire alternator conversion kit.

I removed the old regulator, which was wired like this:

Boatinfo - Mercruiser Service Manual nr. 2 - 1974-1977 All Engines & Drives

I cut and taped off the two yellow wires from the stator. I removed the red jumper wire from the top right of the regulator (which went to solenoid). The other wire which was red/ white stripe was connected to the bottom right of the regulator and according to the wiring diagram goes to the ammeter. I cut and taped that off at the regulator because I read that an alternator might generate to much current and could burn up the wire and or gauge

I ran the red wire from the alternator directly to the solenoid, and the ground to a valve cover bolt. I thought I was good (although obviously the ammeter wouldn't work anymore). My plan was to replace the ammeter with a voltmeter.

Tried to fire up the boat and it won't start. Turns over, but won't start.

Do I need to have the red/white wire hooked up to something?

any other suggestions?

I told the kids I'd take them out in the boat tomorrow. Any help would be awesome. Thanks in advance.

 

[RammaR]

Re: mercruiser 470 alternator conversion no start wiring question

I just did this conversion on my '78 Ranger -- I was stumped on the wiring until I found this. New Page 1

Start on page 11 for the wiring section. I had the engine out of the boat at the time, so I pulled the stator but I you can leave that in - just disconnect the wires. The power wire coming over from the alternator connects to the same point the on the solenoid that the battery does. Then splice / solder the other two wires from the voltage regulator together as shown in the diagram and you should be good to go.

I can take a picture tomorrow if that would help. I've had it out a few times now and the alternator is working well.

Good luck!

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

thanks ramma. the wiring on my voltage regulator was not exactly like the one in the instructions you sent. I think I have the older version (its exactly like the one in the 74-77 manual).

I would like to see a picture of how you wired yours up if you get a chance.

Thanks for helping me out.

 

[RammaR]

Re: mercruiser 470 alternator conversion no start wiring question

Here is the "before" pic (ignore paint condition):

And here is now -- note I completely removed the voltage regulator.

Basically, the stator wires are disconnected / removed. Then the other 2 wires that are connected to the voltage regulator get moved over to the side of the starter solenoid where the battery wire and new alternator wire go. The post on mine has maybe 5 wires connected, it's tough but I didn't want to add a terminal strip just yet.

I didn't have to modify the wiring to any other part of the starter solenoid. Just attached more wires to the one lug.

Good luck.

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

thanks. I just tried it exactly as you have it with the same 4 or 5 wires on the solenoid post- alternator, battery, 2 wires from regulator, and one other one. Boat still turns over but won't start.

Now I'm wondering if I disconnected a wire or blew a fuse or something when I was installing the alternator, moving the coil, etc. Time to get out the test light and multimeter I guess.

I appreciate the picture.

The only wire hooked to the other side of the solenoid is the yellow starter wire, right?

 

[olazabel]

470 wont start. where do I go from here??

470 wont start. where do I go from here??

Yesterday morning my 1978 merc 470 ran fine, but wouldn't charge, so I decided to install the 1-wire alternator kit I bought.

I had to move the coolant reservoir and the ignition coil to make room for the alternator

I cut the two yellow wires from stator and taped them off. I also taped off the red/white wire that ran from regulator to the ammeter in dash. The only other wires on the regulator were a black that was grounded to a bolt on regulator, and a red that went from top right of regulator to battery side of solenoid, which I removed I completely removed the regulator and ran a heater hose straight through.

Now, the boat won't start. Turns over, lights, trim, horn, gauges all seem to work.

I don't know where I screwed up. Did I mis-wire it? Did I screw something else up when I was moving stuff around? I'm not sure where to start.

I just read the "troubleshooting the 470 ignition system" PDF thread, but most of that stuff seemed to be for boats that won't turn over.

Any suggestions, or step by step troubleshooting would be great.

I have a test light, multimeter, etc, but am not real electrical savvy

 

[Eric 3.7LX Alpha 1]

Re: 470 wont start. where do I go from here??

Re: 470 wont start. where do I go from here??

You moved the coil.... did you get the wires back on the correct terminals?

 

[olazabel]

Re: 470 wont start. where do I go from here??

Re: 470 wont start. where do I go from here??

You moved the coil.... did you get the wires back on the correct terminals?

I just moved it down about 6 inches to a new bolt, never actually disconnected the wires,

but I would like to know how to test the coil. I know its probably all over the forum, but I haven't searched yet.

 

[Don S]

Re: mercruiser 470 alternator conversion no start wiring question

I merged your two thread on the same subject together. No reason to have two threads, it just confuses things.

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

thanks don. sorry about that.

 

[RammaR]

Re: mercruiser 470 alternator conversion no start wiring question

It sounds like you have everything wired correctly on starting solenoid and alternator. If it cranks but won't start, I'd start looking at the connections to the coil and plugs. Do you have a spark plug tester to see if they are getting juice? Not sure how it would be a fuel issue, but look at that as well if the coil and plugs are normal.

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

Got the boat started after hooking the red/ white wire to the solenoid. I now have five wires -2-Battery, alternator, circuit breaker, red/white from regulator, hooked to battery side of solenoid.

Is this ok?

The ammeter doesn't seem to work anymore. How can I be sure the system is charging with the new alternator?

 

[Don S]

Re: mercruiser 470 alternator conversion no start wiring question

Actually, you don't need that red/white any longer. It just split off the ammeter and went to the regulator. Without that regulator, you don't need it.

Make sure you have voltage to the + terminal of the coil with the key in the run position. Also check while cranking.

It's possible that you just have a wiring touching something it shouldn't and grounding it out.

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

Thanks Ramma. I checked and tightened all the connections as you said. Wasnt getting spark, but then hooked the red/white back up to the solenoid and got spark,
.
The boat then started right up.

I read in another thread that it was a bad idea to keep that wire connected because it sends everything through the dash, but I guess its necessary.

 

[Don S]

Re: mercruiser 470 alternator conversion no start wiring question

Got the boat started after hooking the red/ white wire to the solenoid. I now have five wires -2-Battery, alternator, circuit breaker, red/white from regulator, hooked to battery side of solenoid.

Is this ok? NO !!!

The ammeter doesn't seem to work anymore. How can I be sure the system is charging with the new alternator?

DO NO hook the red/white wire to the solenoid. You now have the main circuit breaker bypassed and the ammeter.
You have a wiring problem, but that is not the cure. Unhook it and dead end the wire.

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

Thanks don. I know I had read that in another thread. So chances are when I hooked the red/white wire back up and the boat started, I just moved another wire that was grounded or something?

Do you think it is bad to leave current running through the red/white? Should I disconnect it?

How do I check to make sure the system is charging (i haven't installed a voltmeter yet.)?

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

Thanks Don. I'll unhook it.

You're a few steps ahead of me.

 

[RammaR]

Re: mercruiser 470 alternator conversion no start wiring question

Glad to hear you got it working -- have a great day out boating. One more thing is make sure you use an automotive belt. We had an industrial grade (fan) belt laying around that was the size needed so we stuck that on for the first water test. After about 5 minutes on the water and running at speed the belt was shredded. Wasn't an alignment issue, just the speed and friction was too much.

Got a good quality automotive belt and it's been fine since.

 

[Don S]

Re: mercruiser 470 alternator conversion no start wiring question

Thanks don. I know I had read that in another thread. So chances are when I hooked the red/white wire back up and the boat started, I just moved another wire that was grounded or something?

Do you think it is bad to leave current running through the red/white? Should I disconnect it?

How do I check to make sure the system is charging (i haven't installed a voltmeter yet.)?

You can disconnect it from the ammeter if you want, there is already a red/white wire going to the ignition switch. Not quite sure why that made it start, unless you just bypassed something. I'm looking at the engines wiring diagram right now trying to figure out why it worked.

 

[olazabel]

Re: mercruiser 470 alternator conversion no start wiring question

Don- I went out and took the red/white wire off the solenoid and taped it up. The boat still started, so I must have moved something else when I hooked it up?

Is there a specific wire on the solenoid that would allow the boat to turnover, but not spark? Maybe the red wire to the circuit breaker?

I guess I'll go through, cleanup and tighten all the connections, and hope the issue doesn't come back when I'm in the middle of the lake.

How do I test to make sure the new alternator is charging the batteries? I plan to replace the ammeter with a voltmeter, but haven't yet.