RTV-900 Stop Solenoid Woes

[gcmiller]

This past winter I had an issue with my RTV-900 where it would not turn off. It didn’t take too long to determine the stop solenoid (aka – fuel shutoff solenoid) had gone bad. It was an easy swap out and all was good until a month ago when the new stop solenoid died in the same manner; meaning the vehicle would not turn off with the key and I had to close the fuel shutoff with my finger to shutdown the vehicle.

I thought it was odd for a solenoid to go bad so quickly, but it was definitely bad, so I chalked it up to bad luck and I swapped it out again. Well, the new solenoid died on me after only 3 weeks. This time the vehicle will not start unless I open the fuel shutoff with my finger first and it turns off no problem.

I see no big deal that the original 16-year-old solenoid died, but not the original and 2 new solenoids since January. I’m trying to figure out what is happening. My best guess is that I cheaped out. Instead of buying the $120 solenoid from Messick’s/Coleman I bought this $40 solenoid off Amazon:

Amazon.com: 12V Stop Solenoid 16851-60014 1685160014 for Kubota RTV900 ZD18 ZD21 ZD221 ZD321 ZD323 : Automotive

Buy 12V Stop Solenoid 16851-60014 1685160014 for Kubota RTV900 ZD18 ZD21 ZD221 ZD321 ZD323: Solenoids - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Does anyone have any thoughts or suggestions of what to look at or troubleshoot before I go spend $120 on yet another solenoid?

TIA,
Gary

p.s. - I'm not sure what's up the "Robot Check." A search didn't show anything. I thought I have enough posts to be trusted. Anywho, it's an Amazon link.

 

[RCW]

I'm not much help as far as the solenoid, but I do buy some aftermarket parts, for the tractor and other things at home.

I've had some bad luck with some pellet stove parts. At a 50%+ discount, it's worth the gamble. If the Amazon offering doesn't work, I know to go OEM.

Stop solenoids do fail sometimes, but they're pretty basic. Certainly should last longer then yours did.

Maybe you're finding reward isn't there, at least for stop solenoids?

 

[Dave_eng]

You have not convinced me your stop solenoid is/was bad.

Have you downloaded the free WSM from Kubotabooks.com?

You need to be doing the test procedure described in the WSM and not just swapping out parts.

There is a timer device which applies power to the solenoid for a prescribed number of seconds to bring the engine to a stop once the key switch is turned to OFF.

You should also test the timer following the WSM procedure as it may be the cause of your problems.

Dave

 

[gcmiller]

You have not convinced me your stop solenoid is/was bad.

Have you downloaded the free WSM from Kubotabooks.com?

You need to be doing the test procedure described in the WSM and not just swapping out parts.

There is a timer device which applies power to the solenoid for a prescribed number of seconds to bring the engine to a stop once the key switch is turned to OFF.

You should also test the timer following the WSM procedure as it may be the cause of your problems.

Dave

Dave, excellent point about the WSM. I have one for my B2910, but I didn't have one for the RTV until now. The test looks pretty simple. I just need to wait for tropical storm Isaias to pass before I make my way out to the barn.

Thanks,
Gary

 

[Mark_BX25D]

I'd be looking carefully at the wiring TO the solenoid. It may have a corrosion problem and is making poor connection. You swap out a new solenoid, jiggling it in the process, and make the connection work for a time. Rinse, repeat.

I don't know that model, but pay as much attention to the ground side as you do the supply side.

A little corrosion can allow you to measure correct voltage with a meter, but it won't allow enough current to pass to make things work.

 

[gcmiller]

I finally found some time to do some more troubleshooting on my RTV-900. I’m leaning towards the problem being a low-quality solenoid, but I haven’t convinced myself yet.

I downloaded the WSM and followed the test procedures. First, I tested the timer relay connector voltage and all was good (12V on terminal 4 with the key off and 12V on terminal 3 with the key on).

Next I tested the timer relay and it was good there too (I hooked up a light and 12V to the relay, as described in the WSM, and the light came on when I removed the voltage from terminal 3 and the light turned off 7 seconds later – just as it should).

Next, I removed the engine stop solenoid and it tested GOOD on the bench. When I applied 12V, the plunger retracted. When I removed the voltage, the plunger popped back out.

After I reinstalled the solenoid, the RTV started on the first try, but that was only because the plunger was already in the correct position, which is out. The RTV would not start after that, unless I used my finger to pull the plunger out first.

What I’m finding is that roughly 7 seconds after I turn off the engine I can hear and see the plunger try to pop out, but it is moving only a few millimeters, instead of the full travel of ½” to ¾”.

The plunger pulls against a C-shaped lever when it retracts. So when it pops out there is nothing that provides resistance. In fact, the C-shape lever provides some assistance to pull the plunger out.

I checked to see if there is some stray voltage on the solenoid that may be trying to keep it retracted, but there is none. I also checked for corrosion, poor connections/connectors, but all looks good.

I’m at a loss. I THINK I have a bad solenoid, but I don’t KNOW I have a bad solenoid. Any ideas or do I throw $120 at it and hope for the best?

Thanks,
Gary

 

[Dave_eng]

I would like to look at the parts illustration for your machine but discovered there are many different models of RTV900
Can you please clarify which one you have.

Dave

 

[gcmiller]

I would like to look at the parts illustration for your machine but discovered there are many different models of RTV900
Can you please clarify which one you have.
View attachment 47055

Dave

Dave, I have the RTV900G (first in the list).

 

[Mark_BX25D]

Bad connections on either side, supply or ground, could do that, but you've checked for that. If you used a test light and not just a meter, I'd say it's time to roll that $120 dice.

 

[Dave_eng]

As you look at these images keep in mind I have not worked on this engine.

I suspect there is a missing spring. Particularly one called a start spring.

The solenoid, if it has no spring inside, has to be working against a spring to return the plunge to a position where the engine can start..

There is an external spring but also an internal one.

Worth checking out

Dave

 

[gcmiller]

The external spring is there for sure. I have not taken things apart enough to see the internal spring, but I triple checked with my fingers that the arm is indeed putting tension on the solenoid to help pull it out, so I feel good about the springs.

Next, I removed the solenoid and quadruple checked that the arm is naturally moving to the position it would be in if the solenoid were in the out position, making me feel even better about the springs.

I bench tested the solenoid again and all was good (again), so this time when I reinstalled the solenoid I was very careful about how I positioned it. The solenoid has two slightly oval holes used to bolt it to the motor and there’s just a little bit of wiggle room – maybe a millimeter or two. When I bolted it back this time I made sure it was mounted as far in the direction of the extended position as possible and now it’s working. I’ve tested it half a dozen times and it continues to work.

I’m still a little pessimistic about it, but it seems right now that my problem with this third solenoid was probably positioning. Or Mark was right from the start and it was corrosion or a bad connection, but this thing is super clean and I checked connections dozens of times. I’ll keep an eye on it and see if the problem returns. As I said, I’m not convinced the problem is solved for good, but it’s hard to troubleshoot further when it’s working.

The problem with the first two solenoids was different, they would not retract with voltage applied. I still had the last one in the garage and I confirmed it was bad with my 12V power supply. I tossed the original, but it was 16 years old so I’m going to tell my self it was bad.

Thanks for all the help,
Gary

 

[Mark_BX25D]

That's frustrating. I hate problems that 'solve' themselves, because you can't be sure they won't unsolve themselves, usually at the worst possible time.