310-8 will not crank

[urdrwho 0]

Personally I would like to disable the entire safety interlock circuit but my 17 year old is going to start doing so mowing so I will leave it intact.

For a long, long time every now and then when I turn the key to start the tractor, nothing happens, not starter engaging ...noting. Sometimes if I sit there is push hard on the clutch pedal it will engage; sometimes if I sit and rock the tractor a bit it will engage and then sometimes nothing works. Tonight nothing was working and I gently pushed on the mower PTO and just as I started to push with resistance it cranked.

Recently the seat safety switch stopped working and I could get off the tractor to move a branch without it stopping. Yeah! Tractor seemed to run just fine without the switch working.

I believe it is a safety switch issue but how do I determine which one? My service manual says I have three switched the seat, drive and PTO. It doesn't show their locations ...yea the seat is self explanatory.

There is a switch I know if that operates when the brake is engaged. Is it the drive safety switch.

There is a switch that the PTO lever hits and is located by the battery. I would guess it is the PTO safety switch.

How can I isolate the problem to find which switch? The PTO is high on my list and maybe I could jumper the connector? If I remove the connector does that make it a dead starting situation?

[rmaynard 15,417]

:woohoo:

First thing I would do is take a look at the wiring diagram. If you don't have one, you can download a manual from MyWheelHorse.com.

I would do a process of elimination. Bypass the PTO switch. If that doesn't fix it, bypass the clutch switch. Once you have determined which switch is the culprit, hook the other switch back up and make sure it still works. Then get some new switches and correct the problem properly.

I am an advocate of proper use of safety switches. A temporary fix to get you by is okay.

[urdrwho 0]

First thing I would do is take a look at the wiring diagram. If you don't have one, you can download a manual from MyWheelHorse.com.

I would do a process of elimination. Bypass the PTO switch. If that doesn't fix it, bypass the clutch switch. Once you have determined which switch is the culprit, hook the other switch back up and make sure it still works. Then get some new switches and correct the problem properly.

I am an advocate of proper use of safety switches. A temporary fix to get you by is okay.

Thanks for the tip about where to find the wiring schematic. I found it on the site.

Darn tractor started without a problem this morning. Intermittent electrical problems are a pain! Now I must wait to see when it happens again. Hopefully it doesn't happen when I am way out in the field.

So who knows except that I can mow today. Just don't shut it off far away from the house. javascript:emoticon('')

[kpinnc 11,867]

Not sure what year model your 310-8 is, but my 1987 one had a bad "low oil" switch in the engine oil pan. It's basically just a float-type switch that opens the "start" interlock, resulting in the exact same problem you describe. No click, nothing.

On the 1987 model, the only three interlock switches that effect starting should be low oil, clutch, and PTO engagement. The seat switch comes into play once the tractor is running, and should only ground the ignition if closed while the PTO is engaged.

You may also want to check the starter key switch itself.

Kevin

[WH Raider10 17]

I had the same thing happen a few weeks ago. I was tilling in the rain and I parked the 312-8 under the trees. After an hour the low oil light was blinking and I couldn't restart it anymore. The oillevel was fine but probably one of the contacts from the safety switches became wet from the rain. The next day it started right up.

Pieter-Jan :woohoo:

[Boston Horse 2]

So - I am experiencing the exact same problem as urdrwho... I tested the seat switch, PTO switch and the clutch switch, and they all seem fine. I checked the fuses with a volt meter - OK. The only thing I can think of is the oil float switch is bad. How can I temporarily bypass this switch to see if it is the problem? Right now, I get no clicking - nothing. Its like there is no battery in the tractor. I would love some help on this!

[Tim 97]

i had the same problem with a 314. brought it in to a dealer

they told me the ignition switch is grounded to the plate that is on

the plate makes contact through the mounting screws

it is common for the screws and the area between the plate to rust up

they just cleaned up the area around the screws and i was good to go

[Boston Horse 2]

Tim - good idea, but I believe the only purpose of the ground on the ignition is to shut the engine off - not to get it running.. but I certainly can be wrong on that. I also just looked at the "Demystification Guide" and tested the ignition switch, and that is fine too... AAARRRGGGG!!!!

[Boston Horse 2]

So this is where I need some true expertise... On my 1987 WH 310-8, I have not been able to get it started after I accidentally shorted out the ignition trying to repair the chain for the deck (insert rookie comment here). Anywho - I FINALLY traced the problem to this relay. I believe this is the culprit as when I remove all 4 wires attached to the relay together, the mower wants to start. The only issue is that I have to have the blades engauged to start. So - my questions are -

1) can anyone supply me with a part number for this relay?

2) Is there any way to test this relay to see if it works? I already connected the case of the relay to the battery and the terminal on the far end to the positive - and it clicked, but I got no power to the other two posts...

3) Also - any thoughts as to why the PTO has to be engauged to start the tractor? Its entirely possible I reversed a wire in my haste to get this thing started... any thoughts?

Here is a pic. It says 3006 on the steel and H B S on the three leads coming off.

[Save Old Iron 1,566]

Is there any way to test this relay to see if it works? I already connected the case of the relay to the battery and the terminal on the far end to the positive - and it clicked, but I got no power to the other two posts...

You are close - very close on this one. Tim was giving good advice pointing you toward one of the possibilities which can cause intermittent starter operation. Corrosion on the relay case or on the tractor frame where the relay mounts is a valid reason for the issues you are seeing. It is correctable by cleaning the relay case and the tractor frame at the mounting area.

The case of the relay is metal and the case bolts to the chassis - so the case should be grounded - electrically connected to the battery negative (-) terminal. You have already identified the trigger terminal and activated the solenoid - you do have the polarity reversed (case should be negative and trigger terminal positive) but that will not corrupt your troubleshooting. Your confusion is due to the expectation of voltages being seen on the two remaining relay terminals.

Even with the relay activated, battery voltage will not be present at the other two relay terminals. The function of the relay contacts when activated will be to make the remaining two relay terminals short together. This is identical to the function of a starter relay but the lockout relay is not designed to carry heavy current - just a few amps at most to energize the starter relay.

So with the relay wired directly across the battery terminals and energized, the remaining two relay terminals should show near 0 ohms resistance with an ohmmeter. When you remove the battery positive jumper from the relay, the relay de-energizes and the ohmmeter should show a high (meter in overrange) resistance.

The diagrams below demo the principle described above. The relay shown is a starter relay but the lockout relay is IDENTICAL IN FUNCTION - it's just not designed to carry heavy current thru the switch contacts like the starter relay.

[Boston Horse 2]

SOI - you are a man among men - I love the diagrams - very helpful. So - I just put the negative from the battery to the case of the relay, the hot from the battery to the trigger terminal on the relay (far right stud, labeled "S") and I checked for Ohm's on the remaining two studs. Drumroll please... nothing. I hear the relay clicking but there is no change in Ohm's at all on the remaining two studs. Can I get my shovel out and bury this relay yet or is there something else I can do? More importantly, where can I get a new one? I can't believe that a silly mistake like sparking the ignition killed this relay... but it must have. Also - does this relay have anything to do with the PTO switch? For some reason, when I connected all the relay wires together, the tractor only starts when I have the blades engagued? Is this related to the relay or do you think I put a wire on backwards elsewhere? THe PTO switch has 6 terminals, but I am only using 4 of them. Do the wire orders matter?

[kpinnc 11,867]

The PTO actually has two switches. One is closed when the PTO is engaged, and is in series with the seat switch which is normally open. When you close the seat switch (remove weight from the seat with the PTO engaged), it grounds the coil and shuts off the tractor.

The second PTO switch is normally closed (when the PTO is off), and is part of the "start" interlock, being in series with the clutch switch. Those two PTO switches are identical, but are wired differently at the plugs. Try switching the two PTO connector plugs to make sure they aren't backwards.

Good luck!

[Save Old Iron 1,566]

Can I get my shovel out and bury this relay yet or is there something else I can do?

You could remove the metal case from the black plastic base and inspect the contacts. They may be able to be cleaned like ignition system points.

The world of serious tractor fixin' hangs in the balance as we await your next move.

[Boston Horse 2]

CASE CLOSED!!! SOI - you were right. I was able to open up the metal case on the relay by prying the crimps open and unsoldering the ground. When I looked at it, I noticed that the points were clean, but they were not touching under load... so I simply bent the tab a hair and got them to touch. That was it. I have been staring at wiring diagrams and RS discussions for 4 days, laying under the tractor in the garage for just as long and testing every inch of this machine to be fooled by a relay that was not making contact... PROBLEM SOLVED! I have no idea how this tab could have bent when I shorted the ignition, but it did, and its all set. With regard to the tractor only starting with the blades engauged, I took KPINNC's advice and checked the two switches on the PTO switch to figure it out, and that is all set too. Victory!!! Thank you all for your help!

[Save Old Iron 1,566]

so I simply bent the tab a hair and got them to touch. That was it. I have been staring at wiring diagrams and RS discussions for 4 days, laying under the tractor in the garage for just as long and testing every inch of this machine to be fooled by a relay that was not making contact...

Yep, you can make the problem and the troubleshooting sound as sexy as you want ... but the fixes are generally very simple. I congratulate you on your stick to it attitude and the fact you were willing to do an autopsy on the defective part.

I fully expect you to be one of the folks who chimes in on the next post that requires help in this area. You are now the official RS relay adjustment expert.

BTW - a little clarification on the B H S terminal designations - the relay you repaired is the classic style "horn" relay used decades ago in automobiles.

B- battery

H - horn

S - switch

case is grounded as you saw with the braided strap.

[Save Old Iron 1,566]

Tonight nothing was working and I gently pushed on the mower PTO and just as I started to push with resistance it cranked.

urdrwho, we didn't want to to forget about your issue.

The fact the PTO lever requires excessive forward force to activate the PTO switch suggests the physical position of the switch or physical position of the PTO lever requires attention. The PTO lever is mounted thru a plastic collar on the dash tower. If the plastic collars breaks, the PTO lever moves away from the safety switches somewhat, probably enough to cause an intermittent issue by not engaging the PTO safety switch(s). Replace the collar or readjust the position of the 2 safety switches closer to the cam on the PTO lever.