'76 115 Charging/Cranking voltage issue

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Sorry ezeke, I must have mistinterpreted what you said earlier, I thought that you meant that on this particular engine that seeing the higher voltages was normal, but now I see what you mean about it being higher until I get the resistance problem fixed. Also, right now there are no accessories on the boat, the only load on the battery is cranking the engine, so I most definitely have either a cable or solenoid problem. Gonna run through the tests today and I'll post back.<br /><br />By the way is there an easy way that I can disable the ignition for testing purposes? Just don't want it to fire up, because once it starts it will continue to start no problem, and I won't be able to continually crank to go through all of the above tests. I don't have the safety lanyard to kill the ignition on this boat, so can I just ground out the kill circuit to keep this thing from starting, and how do I go about doing that? Thanks.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Bump....Just need to know how to disable the ignition, so I can crank without starting. Thanks.

 

[Seasport]

Re: '76 115 Charging/Cranking voltage issue

Disconnect your kill switch (safety lanyard).

 

[ezeke]

Re: '76 115 Charging/Cranking voltage issue

As long as the key is turned to OFF and the harness connected, the powerpack is grounded and the motor will not start.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Oh OK, I got ya ezeke. Just leave the key off, which grounds the powerpack, and use a separate jumper or switch to crank at the solenoid. I use the two big posts on either side of the solenoid to connect my switch between right? Thanks.

 

[Tom Scully]

Re: '76 115 Charging/Cranking voltage issue

Use the "big post" with the wire from the battery and the small positive terminal to the coil of the solenoid. You would need a large high current switch to jump the big posts.<br />Jumping the big posts is a way to bypass the solenoid contacts, as mentioned by upinsmoke eariler.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Thanks Tom. I do have a pretty heavy starter switch that I used when I worked on cars. I was gonna use that for jumping the solenoid and cranking while I use the meter. I will start by jumping the two big posts on the solenoid and see of I can diagnose a bad solenoid right off the bat. <br /><br />When you say the small positive terminal on the solenoid, are you talking about the one directly above the big post with the + battery cable on it? There are two small terminals on the solenoid, I'm assuming one is + and one is -, so I have to jump from the + battery cable big post to the small + terminal on the solenoid.<br /><br />Thanks.

 

[Tom Scully]

Re: '76 115 Charging/Cranking voltage issue

Not sure of it's position on your solenoid.<br />The small + terminal I was refering to should have a small wire, 16-14 gauge, on it which comes from the ignition switch.<br />From the + batt cable on the big post to the small +, solenoid coil, terminal is correct.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

I got ya, thanks.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Originally posted by Seasport:<br /> Hey Cricket<br />Your problem could well be the solenoid where the contacts fail as they heat up.<br /><br />You should be able to isolate the problem using a voltmeter.<br /><br />Here's some instructions I have given others in case they are of any use.<br /><br />Starter problems can be hard to diagnose. It doesn't take much voltage drop to upset correct operation.<br /><br />During cranking the starter motor current flows from the battery +ve terminal through the battery switch, solenoid (& connecting cables obviously) to the starter motor and then back to the battery –ve terminal through the ground connections and –ve battery cable. There is a lot of current flowing so any poor connection in the whole circuit will lead to excessive voltage drop there (& heat build up) and poor starter motor performance. This includes the ground connections from the starter motor body back to the -ve battery terminal. You will get voltage drop here too which takes away volts from the starter motor.<br /><br />I assume you have access to a voltmeter. If so, I suggest you start by measuring the DC voltage directly across the starter motor during cranking under load, i.e. with the red probe of the meter on the starter motor +ve terminal and the black probe on the case of the starter motor. If this reading is greater than about 9.5V suspect a starter motor problem. Easiest if you have someone else to turn the starter motor over for you while you take the measurements.<br /><br />If the voltage is less than 9.5V you are dropping volts somewhere else. Check and clean all of the connections from the +ve battery terminal to the starter solenoid (including the battery switch if fitted) and from the solenoid to the starter motor. (As a clue, any bad connection should get warm when cranking).<br /><br />Check & clean also the -ve battery terminal & powerhead ground connection and also the ground connection from the starter motor to the engine. On some motors the -ve battery terminal is connected directly to the starter motor body and on others it is bolted elsewhere to the powerhead.<br /><br />If this doesn't fix the problem, you may have bad cables or a bad solenoid. If you have access to a voltmeter you can use the following tests to isolate the problem. You need to measure the voltage drop across each part of the circuit while cranking the motor. Start by measuring the voltage from the battery +ve terminal to the battery side of the starter solenoid (large terminal), i.e. meter red probe to +ve battery terminal and meter black probe to the large solenoid terminal that is connected back to the battery. This voltage should not be more than about 0.3V – 0.5V. If it is suspect a bad cable or connection here somewhere.<br /><br />Next measure the voltage directly across the solenoid when the starter motor is cranking (or trying to crank), i.e. meter red probe to battery side of the solenoid and meter black probe to the starter motor side. This voltage should not be more than about 0.2V.<br /><br />Next measure the voltage between the solenoid (starter motor side) and starter motor +ve terminal. This should not be more than about 0.3V. If it is too high check the cables and connections here.<br /><br />Finally measure the voltage between the starter motor case and the battery –ve terminal. This shouldn’t be more than about 0.3V. If it is check for a good solid and clean ground connection between the battery –ve cable and powerhead or –ve battery cable problems.<br /><br />Make sure your battery is in good shape. Battery voltage when cranking will also vary with condition of the battery. The battery voltage shouldn't drop below about 10V when cranking.<br /><br />The voltages mentioned above are indicative. They will vary a bit with starting system. What you are looking for is an excessive voltage drop. The voltage readings may well go up and down a bit as the motor turns over slowly but just try to choose a consistent set of readings. The key is that the starter motor needs at least 9.5V to operate properly.

OK Guys, I went through all of the procedures Seasport posted above, using a short set of good cables with the battery in the stern, and everything seems to check out. All of the voltages that he said I should see I saw, with one exception. From the + terminal on the starter to the starter case, while cranking, is giving me about 10.5V or a little higher, and Seasport you stated I should see no more than 9.5V.<br /><br />My question now is, can this starter issue cause an excess charging problem in my system? I can't find any other voltages out of spec while cranking except this one, but I'm still getting approx. 15.5 - 15.7V at idle and about 16V when I rev up to about 3K RPM, I don't want to rev any higher than that on the muffs.<br /><br />The engine/starter cranks very well, and the battery held up well under all of the cranking to do these tests. I did notice that when I started the engine back up after all of these cranking tests, that the voltage was normal, the thing sat idling and charging at about 12.8 - 13.2, which I guess is a little low. I figured it was because the battery was so discharged from all of the cranking...adding extra resistance...so the charge voltage was lower. Pulled the battery and put another fully charged battery on, and went right back to the same problem, 15.5 - 15.7V at idle and about 16V or so at 3K RPM.<br /><br />Really hope the starter is the problem, because I'm starting to get frustrated, I was sure I'd find a voltage drop(resistance) at the solenoid, but everything checked out to the 1/10 of a volt that Seasport posted, pretty much exact to what he said they should be. Will the starter cause this charging problem? Thank you guys for sticking with this.<br /><br />Thanks, Mike.

 

[Tom Scully]

Re: '76 115 Charging/Cranking voltage issue

Over 9.5 volts at the starter is Ok as stated by Seasport: "The key is that the starter motor needs at least 9.5V to operate properly."<br />The starter is not the cause of the excess charging voltage.<br />What kind of battery charger and batteries are you using? The battery acts as the regulator in this system, you need to have a good quality marine grade battery.<br />Sounds like the fully charged battery you installed after the cranking tests was possibly over-charged. The voltages you were getting after the cranking tests were ok, eventually the voltage would have come up to 13.8-14.1.<br />If all else fails you can install an aftermarket voltage regulator.<br />The cranking test voltages indicate your starter needs servicing, (brushes and or commutator), if you experience a drop in cranking speed again.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Hi Tom, I was going off of the second paragraph that Seasport stated, as below:<br /><br /><br />"I assume you have access to a voltmeter. If so, I suggest you start by measuring the DC voltage directly across the starter motor during cranking under load, i.e. with the red probe of the meter on the starter motor +ve terminal and the black probe on the case of the starter motor. If this reading is greater than about 9.5V suspect a starter motor problem. Easiest if you have someone else to turn the starter motor over for you while you take the measurements."<br /><br /><br />According to this paragrpah, it would lead me to believe that what he is saying is that if I see a greater voltage than 9.5V across the starter while cranking, then I should suspect a starter motor problem. I was getting 10.5V across the starter while cranking, did this particluar test 4 times, and tried it with two different meters, just to be sure, and all 4 times I got 10.5V across the starter, wasn't sure if 10.5V was an allowable limit though, and I didn't think it was causing my charging problem, but wasn't sure.<br /><br />So there's no possible way that a bad starter(which I'm not sure I have) can cause excess charging voltage? Everything else checks out good, I cannot find what would be causing this.<br /><br />Also, my battery/batteries are both brand new Deep Cycle marine batteries. One is a Power Master 650MCA Deep Cycle and the other is an Interstate 690MCA Deep Cycle, the Interstate is my fiends, but he just bought it 2 weeks ago and hasn't used it yet. I put both of them on my 10amp charger for about 2 hours before I started this test, so they would both be fully charged. I don't think they can get overcharged on my charger, as it kicks down to the 2amp trickle charge mode, when the battery is fully charged(unless of course, that's broken). I also did switch back to the weak battery afterwards and let it run for a while and it did come back up to "Normal", for a couple of minutes and then kept going forward into the 15.5V range.<br /><br />Really puzzled here, not sure where to go next. Figured I'd see something wrong with the solenoid, but voltage checks out across the solenoid. I would really like to fix this the right way, and I know it's going to bother me if I don't, but at this point I'm really leaning towards putting an aftermarket regulator on the motor as you stated Tom. Any ideas on what kind/brand and how I go about doing this? Still would like to try and fix it the right way though.<br /><br />Thanks, Mike.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Bump, hope this post didn't get too long for people to read.

 

[Seasport]

Re: '76 115 Charging/Cranking voltage issue

Get back to you shortly Cricket.

 

[Tom Scully]

Re: '76 115 Charging/Cranking voltage issue

Cricket,<br />Check out this post: <br /> web page

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Hey Tom, well looks like I may be chasing a ghost huh? I think my solution may be installing a regulator, as was the solution in that post you sent me. <br /><br />I've actually read that before, but got so focused on solving what I was sure was a high resistance problem, that I forgot all about what andy6374 had posted and it's actually really good information. I feel pretty comfortable following his advise, since he states that he has spoken to the engineers who designed the stator, and it seems this is a somewhat common issue with unregulated charging systems. Even though I have used a brand new Interstate Deep Cycle Marine battery, it hasn't solved my problem, and I can't find any high resistances in the charging circuit at all.<br /><br />So I guess my next question would be, what type of regulator should I use and where can I get a quality one? Also one other question, these unregulated charging systems are very low amperage systems, I've been told, so will installing a regulator still leave me enough amperage to charge my battery, or will the regulator not affect my charging amperage?<br /><br />Thanks for all of the help, Mike.

 

[Tom Scully]

Re: '76 115 Charging/Cranking voltage issue

You can use a regulator from a later model engine, 115 hp's after 1980 thru at least 1983 had separate regulators, part #0173640, they run around $110-$120. You could probably find it for $40-$50 at a place that sells used outboard parts or on e-bay; heck I might even have one in the garage! Or you can use a regulator from an omc sterndrive such as a 0383440, (ARCO VR404 or 405). They cost around $35-$40 but do not offer as clean of an installation and may require some "rigging". <br />The regulator will not substantially effect your charging current.<br />Let us know how it goes.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Thanks Tom, I would rather get the correct part that would fit better(from an outboard), I will try and find a used one first. Is there any Radio Shack type of regulator that I could use, just for ease of getting a part there? <br /><br />Also, I'm not completely sure on how I go about wiring it in, do you have any tips on how I go about installing it, electrically anyway? Thanks.

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Bump

 

[Cricket Too]

Re: '76 115 Charging/Cranking voltage issue

Bump, just need to know how to wire a regulator in, and if I can use something from an electric supply house or Radio Shack or something. Thanks.