2016 Magnum - 140 hours & starts (cranks) sometimes but not other times

[KX500]

Got this thing about a year ago 90 hours on it. Price was good, figured how could I go wrong? Little did I know, what a frustrating piece of equipment it would be.

And it is a great mower, but the worst at starting of anything I've ever owned! And I really mean cranking - if it'll crank, it'll start.

It has pretty much always cranked when cold/not been run.

But after than, all bets are off. Anytime you've used it for any length of time, it simply may not crank if you go to start it again. Or it will - can't really seem to find a rhyme or reason.

Anyway, finally a month ago, mower wouldn't crank at all.

So, I replaced the solenoid and it worked flawlessly for about a month - would crank anytime I cared to try it.

But since then, it has returned to it's old ways - starts cold and maybe not any other time.

I do have another solenoid, but am starting to doubt that is the real problem.

Why would a new solenoid only work perfectly for a month?

And yes I've figured out Plan B for starting - plastic handled screwdriver across the solenoid terminals. But I'd rather not have to rely on this method of getting the thing to crank, when it won't otherwise.

So anyway, any clues as to what my really problem is here?

The solenoid is easy to change, but I'd really like it to stay fixed this time.

Thanks.

 

[Rivets]

Check your battery to chassis ground first. They love to come loose and corrode. If that doesn’t help go through this procedure and report back.





Electrical* problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position q(you may need an assistant to sit in the seat to override the safety switch).*

Fifth, check for power at the starter while holding the key in the start position (assistant again).*

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.

 

[KX500]

Thanks for the reply. I did complete a few of the things I can do by myself.

For steps 1 & 2, Battery is putting out 12.4 Volts and I get that reading at one of the terminals on the solenoid as well.

One of the wires coming off the battery goes to the solenoid & the other mounts to the engine - the ground I assume. But no issue with this connection.

There are no other wires attached to these battery wires, so don't know what to do with step 6.

I will work on steps 3-5 when I can find an assistant. Partial answer on solenoid - yes 3 terminal and about 1 month old - no corrosion between it & Stainless Steel fender, where it mounts.

However, for these steps, if you turn the key and it cranks, is it safe to figure that 12.4 V is getting to where it is supposed to be?

I guess, I'm wondering if some of these steps apply mostly to when the mower gets to one of it's 'not cranking' episodes.

And yesterday something interesting happened with it. My wife mowed for a while and even had to get off once or twice and it restarted fine. She stopped again, right before putting it in the shed and of course then it would not restart.

I tried it about 3 hours later, no go. I tried it again a couple hours later, still no start.

So I resorted to the screwdriver across the solenoid to start it and move it into the shed.

Out of curiosity, I tried the key then and it started fine. Literally, 1 minute earlier that didn't work. Tried again & starts again. Seemed like it would start 100X in a row, if I felt like sitting there trying it.

So I can't help but think - the only thing that changed in that 1 minute was that it started & ran for about 30 seconds.

Did that matter or is it all random?

 

[Rivets]

Sorry to say this, but you basic understanding of electrical circuits is weak. This means that it is going to be a little more difficult to diagnose you problem. Second, you will need to get an assistant and go through the procedure in order, no jumping around and post readings for each step. Third, you should have a small wire going from either the battery + terminal or the terminal on the solenoid which the battery is connected to. Fourth, when you say the there are no problems with the ground connection at the frame, how do you know? Remember in the procedure I I said was that assuming was not allowed. I need you to double and triple check every connection, as I’m moving toward the conclusion that a bad or dirty connection may be your problem. Electrical troubleshooting is not something that you can take shortcuts with. Let me tell you from years of experience, unless you are a very experienced electrical troubleshooter, shortcuts will only drive you nuts and in need of many stiff drinks.

 

[KX500]

Got my assistant ready and then worked through the steps. Here is what I found:

1) Fuses checked, battery terminals corrosion free. After running it for a coupe minutes, battery reads 12.7 volts.

2) 12.7 Volts at large terminal on solenoid

3) 12.7 Volts at small terminal on solenoid

4) 12.7 Volts at other large terminal on solenoid

5) 12.7 Volts at starter

These reads were all taken without the assistant.

Then repeated steps 3-5 and got the following while engine is cranking:

3) 0.4-0.6 Volts at small terminal on solenoid
4) 12 Volts at other large terminal on solenoid
5) 10-11 Volts at starter

If this doesn't help, it will take me a while to check all connections.

Also, the battery to solenoid to starter circuit is pretty simple (even for me); red from battery to solenoid, black from battery to engine/starter mounting bolt, red then from bottom of starter to other big terminal of solenoid. Obviously I'm leaving out the wiring for the small terminal, which is harder to see and probably a bit more complicated.

Anyway, does any of this help?

 

[Rivets]

Did the engine start when you ran these tests?

 

[keakar]

Got this thing about a year ago 90 hours on it. Price was good, figured how could I go wrong? Little did I know, what a frustrating piece of equipment it would be.

And it is a great mower, but the worst at starting of anything I've ever owned! And I really mean cranking - if it'll crank, it'll start.

It has pretty much always cranked when cold/not been run.

But after than, all bets are off. Anytime you've used it for any length of time, it simply may not crank if you go to start it again. Or it will - can't really seem to find a rhyme or reason.

Anyway, finally a month ago, mower wouldn't crank at all.

So, I replaced the solenoid and it worked flawlessly for about a month - would crank anytime I cared to try it.

But since then, it has returned to it's old ways - starts cold and maybe not any other time.

I do have another solenoid, but am starting to doubt that is the real problem.

Why would a new solenoid only work perfectly for a month?

And yes I've figured out Plan B for starting - plastic handled screwdriver across the solenoid terminals. But I'd rather not have to rely on this method of getting the thing to crank, when it won't otherwise.

So anyway, any clues as to what my really problem is here?

The solenoid is easy to change, but I'd really like it to stay fixed this time.

Thanks.

adjust your valves just to be sure

but check the compression release is working as it should, if its not they i will have a hard time cranking because of that, and that in turn pulls a lot of amps on the solenoid contacts overheating them, adding to the starting issue.

also, it doesnt sound like an issue you have if its not turning over, but often a dirty poorly functioning auto choke can cause head scratching starting issues. never overlook checking the choke is snapping back open as it should when an engine is acting strange only sometimes

 

[KX500]

I probably did each of those tests twice. It probably started half those times, before I told the assistant to stop trying to start it.

I wasn't concerned with it starting but cranking. If it'll crank, it'll start - unless u stop trying.

 

[Rivets]

When it stops cranking is when we need the voltage check.