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Discussion Starter #1
Hello, first time posting here. I tried looking around older posts but have yet to find the fix. I have an HH120 with the belt driven starter/generator thats on a Sears Super 12 tractor. The starter barely turns over the engine even with a jumper attached to it. It seems it has got even worse now, the starter no longer can even turn over the engine at all. I removed the belt to see if the starter could spin with no load on it, and it just barely did. It was weak enough where i could stop it easily with my hand. I've tried cleaning all the electrical connections and grounds with no luck. To see if it was the starter, i took an identical one off of another working tractor and put it in this one, but it still just barely turned so i know its not the starter itself thats the issue. The battery and battery cables are brand new on this tractor. I was thinking of swapping out the voltage regulator but im not sure if that even has anything to do with the starting of the engine. Im pretty stumped at this point, hoping someone here can give me some advise on what to try next. Thanks!
 

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You are right that the starter is working right off he battery and the regulator should have no bearing on it but I would check to see what voltage you are getting at the starter...can you do that and check back?...also...Tractor-Holic has that tractor and seems to know that engine pretty well....if you spot a post by him...shoot him a PM
 

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Discussion Starter #3
Just checked the voltage, with the key in the start position it looks like the starter is getting around 12 volts. The starter still has the belt off and only just barely spun
 

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Have you tried just turning the starter pulley by hand. Maybe has seized bearings or winding hitting magnets?
 

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Discussion Starter #5
The starter turns very easily and free by hand. Theirs a very small bit of resistance, unless its normal, but definitely nothing seized in the starter.
 

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have you verified that the voltage of the new battery is at least 12.4 volts. I assume that there is a starter relay somewhere. you may want to do voltage drop tests. Info on that starts in section 17.35 of this manual
web.ncf.ca/da229/smallengine/mtd-769-01415_electrical-2.pdf
 

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Discussion Starter #7
Yep, battery is showing a bit over 12 volts. If I'm correct, I don't believe their is a starter relay. Thanks for the Manual, I'll definitely run some tests on it tomorrow and see what I come up with
 

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The starter/generators were never noted for being very great at cranking a cold engine ,especially the Tecumseh's which seem to have a high compression ratio..

The dinky battery isn't quite up to the task either in my opinion--these units draw a lot of amps during cranking and it would have been better if Roper made room enough for a full sized car battery under the hood..Despite my HH120's having decent starter/generators,I often must use another larger battery to jump start them,especially in winter..

Your unit sounds like it is lacking a good ground or other connection seeing two of them did the exact same thing...I've read here that it is important to file down the bracket and part of the starter/generator that bolts to it to ensure a good ground--my HH120's had a braided ground strap there also..

Another weak spot is the ignition switch itself--they were a lousy design in my opinion,having full battery voltage to the starter being passed thru it ,it has heavy copper contacts inside and they get arced and corroded over time,and can prevent full power from getting to the starter--a quick way to test if its the switch is to use a jumper cable from the battery positive ,directly to the post on the starter/generator that has the heavy gauge red cable from the ignition switch on it..(IT is tough to access though!)..

If it cranks over fast by jumping it,then it is likely the ignition switch "start" contacts inside are acting as a big resistor and not letting enough amps flow..

Some install a Ford starter relay to by-pass the "crank" function of the ignition switch to eliminate this trouble and avoid having to hunt down an original type ignition switch and the aggravation of installing one,its not the easiest thing to access..

I posted on another thread in the Craftsman/Sears forum ,a video that shows a quick way to test the starter/generator to see if its working properly..yours is probably OK seeing both the ones you tried do the same thing,but its possible both could have a failed winding or something too,though ,but not likely..
 

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Yep, battery is showing a bit over 12 volts. If I'm correct, I don't believe their is a starter relay. Thanks for the Manual, I'll definitely run some tests on it tomorrow and see what I come up with
I've had one read 12.2 and wouldn't crank a little 12 hp briggs.
 

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Discussion Starter #10
So I've tried a few things. First I took the ignition switch out and cleaned all the terminals and the connectors on all the wires going to the switch.
Next I read up on that manual and did a voltage drop test. I had the red lead on the positive battery terminal and the black lead on the F terminal of the battery. With the key in the off position I got a 12 volt reading. When the key is in the start position, it showed very little or no voltage.
I tested the starter with a jumper pack, and it spun up very fast right away. I then tapped the other terminal and it stopped pretty fast, so I can confirm the starter itself is good.
I guess the key switch could be the issue. I'm going to take one more look around and make sure theirs nothing else I forgot to check
 

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Hey Alex...can you get a picture of the starter?
 

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Discussion Starter #12
Here's the only picture I have on me right now. I can get some better pics once I'm home. Those connections are cleaned up now, took this picture before in case I forgot the wiring.
 

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You said you used a jumper....from + on Battery to that terminal in your post#12 ...the terminal with the big wire on it?..and still slow?...At this point, although the battery is new I would take t out an d have a load test done..also

.I would pull the starter out and bring it to a parts place that can do a bench check on it
 

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Discussion Starter #15
When I jumped it from just the battery it was slow, when I put the jumper right to the starter on that terminal it spun up instantly which is why I'm thinking the starter must be fine.
 

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You are losing voltage somewhere....you must have a wire or something that is grounding itself...can you get a second pair of hands and do a voltage check while the helper cranks the engine?
From the point at the generator where that big cable is ...just touch the other wire to the chassis and see how many volts you are getting
 

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I took one of my starter/generators to a local rebuild shop,and the guy "tested" it the exact same way as the YouTube video guy did!...

I told him I'd already done that,and wanted him to see if the armature had any defects using his "growler"--he said as long as it motorizes and "brakes",it is unlikely that the armature was faulty..(and he'd be glad to sell me a new one for $90 !)..
He wanted $100 to take it apart and re-assemble it "if no new parts are needed"..
I opted to take it home for free,seeing he said it was likely "good"..
If I wanted to take it apart myself and have him test the armature,he'd have wanted $25..(I know how to use a growler,but he didn't like the idea of letting me use his!)..

When my Suburban 12 started cranking slow and acting like the battery was dead,I put the charger on the battery and it did not seem dead,the amp meter barely went up at all--since I don't use that tractor much I figured the Walmart battery that's a 2015 vintage might be junk--but I put jumper cables on the battery terminals and hooked them to a chevy starter I had lying around,and it spun over like gangbusters--so the battery was fine..

I did some poking around,cleaned the battery terminals,and the cables at the (new) ignition switch,everything was clean and tight,but it still refused to spin over good..

Then I went to the wires at the starter generator--I held the key on "start" and the engine just barely spun over--blub...blub...blub...then I saw a wisp of smoke come off the "A" terminal wire on the unit,and I got my finger singed when I touched it..

I took a wrench and carefully snugged up the nut on the stud,they like to either turn and break off the wire on the inside ,or break off or strip the threads,so be gentle!--if there are two nuts on the stud,hold the bottom one still while tightening the top nut..
...after I did that,it spun over better than it ever did since I got it..evidently it was just loose or corroded enough to block the amps from getting to the starter..
 

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Discussion Starter #18
Im glad to say I've finally got it fixed! I took your guy's advice and really cleaned up the grounds good, i also sanded down the tabs on the starter generator where it bolts down. After I had done that, it was spinning much better and it was able to turn over the engine but was very slow (much too slow to actually start it) I went to check the battery again, still got a full 12 volts from it. Then i had noticed it was rated at 150 CCA. I decided to buy a battery rated at 300 CCA. I put the new one in, and now its turning the engine over plenty fast enough! I even gave it a quick shot of starting fluid and i heard it fire for a second which was a great reward for all the work I've put into this. Thanks for all your help guys!
 

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12V is low for a battery. Fully charged, it should be about 12.6V, and with the engine running, the voltage should be about 13.5-14V or so.
 
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