No start issue

dmoore

Member

Equipment
2006 B7800, RC72-BA 72" mid mount mower, RB 1672 72" rear blade
Feb 8, 2010
78
6
8
62
Exmore,Virginia
So I cut our 4 acres today with my 2006 B7800. Shut it down for an hour for lunch. Went to start it again to wash out the deck and nothing. Fuel solenoid clicks but no starter engagement. First time in 16 years this has ever happened. So I am thinking one of the safety switches must be the problem or blown starter fuse at the starter. Fuse checked out good. I grab a test lead with alligator clips and jump out the starter solenoid while pushing in on the clutch and key in the run position. Nothing. I then tie the seat down as to depress both seat switches. I jump the solenoid again and it starts. As soon as I untie the seat and 2 seconds later it shuts down. The PTO is disengaged if your wondering. So I jump out both seat switches and still the same thing. I am now wondering if the clutch safety switch is the culprit. It seems to be closing the switch externally. Tough to get to the boot to pull it up far enough and jump it out. This is where I stopped for now. At least I got it back in the barn. The PTO safety switch could also be the issue. I looked down in that area and there are two. Thoughts?
 

GreensvilleJay

Well-known member

Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
9,368
3,801
113
Greensville,Ontario,Canada
Without the wiring diagram it's near impossible to say exactly what is causing the 'no start' condition.
old tractor...could have a 'frayed or chewed' wire finally gave out, crap in some switch,loose connection,??
 
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dmoore

Member

Equipment
2006 B7800, RC72-BA 72" mid mount mower, RB 1672 72" rear blade
Feb 8, 2010
78
6
8
62
Exmore,Virginia
Dead battery. Corroded contacts. Bad ground.
Battery is perfectly fine, I can bypass the starter solenoid and it cranks fast. Tractor is immaculate and is stored in my climate controlled building since I bought it new.
 

dmoore

Member

Equipment
2006 B7800, RC72-BA 72" mid mount mower, RB 1672 72" rear blade
Feb 8, 2010
78
6
8
62
Exmore,Virginia
Without the wiring diagram it's near impossible to say exactly what is causing the 'no start' condition.
old tractor...could have a 'frayed or chewed' wire finally gave out, crap in some switch,loose connection,??
Are there wiring diagrams posted here?
 

mikester

Well-known member

Equipment
M59 TLB
Oct 21, 2017
3,038
1,562
113
Canada
www.divergentstuff.ca
Battery is perfectly fine, I can bypass the starter solenoid and it cranks fast. Tractor is immaculate and is stored in my climate controlled building since I bought it new.
Now that you've ruled out typical problems using logic you should simply start buying new parts for your immaculate tractor stored in the climate controlled building. Use the following order:
1. replace starter solenoid
2. replace key switch
3. replace starter
4. replace fuses
 

GreensvilleJay

Well-known member

Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
9,368
3,801
113
Greensville,Ontario,Canada
jumper +12 to control tab of starter solenoid, if it spins, solenoid/starter is fine.
follow 'control wire' back to where ever it goes(some safety switch ?),test there.
 
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woodman55

Well-known member

Equipment
L6060HSTC, RTV 1100
May 15, 2022
716
516
93
canada
So I cut our 4 acres today with my 2006 B7800. Shut it down for an hour for lunch. Went to start it again to wash out the deck and nothing. Fuel solenoid clicks but no starter engagement. First time in 16 years this has ever happened. So I am thinking one of the safety switches must be the problem or blown starter fuse at the starter. Fuse checked out good. I grab a test lead with alligator clips and jump out the starter solenoid while pushing in on the clutch and key in the run position. Nothing. I then tie the seat down as to depress both seat switches. I jump the solenoid again and it starts. As soon as I untie the seat and 2 seconds later it shuts down. The PTO is disengaged if your wondering. So I jump out both seat switches and still the same thing. I am now wondering if the clutch safety switch is the culprit. It seems to be closing the switch externally. Tough to get to the boot to pull it up far enough and jump it out. This is where I stopped for now. At least I got it back in the barn. The PTO safety switch could also be the issue. I looked down in that area and there are two. Thoughts?
I am leaning towards the pto switches, I am thinking the tractor thinks the pto is engaged. Does your tractor have a indicator light in the dash ? That could be one switch and the other for the start circuit. A test light would be very useful.
 

GreensvilleJay

Well-known member

Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
9,368
3,801
113
Greensville,Ontario,Canada
I grabbed the wsm, there's 3 safety switches ( clutch,pto, hst) that all have to be closed to ground the starter relay. you should be able to jumper to bypass the 3 switches. if it starts yo KNOW it's one of the 3 switches and/or their wiring.
if the 'preheat' lamp comes on ,then the main switch is supplying +12 to the starter relay
 
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Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
5,075
2,310
113
North of Pittsburgh PA
Battery is perfectly fine, I can bypass the starter solenoid and it cranks fast. Tractor is immaculate and is stored in my climate controlled building since I bought it new.
Curious, how did you bypass the starter solenoid?
 

B2710HSD

New member

Equipment
B2710HSD belly mower flail water bowser logging bench
Aug 12, 2011
8
1
3
CHEPSTOW UK
So I cut our 4 acres today with my 2006 B7800. Shut it down for an hour for lunch. Went to start it again to wash out the deck and nothing. Fuel solenoid clicks but no starter engagement. First time in 16 years this has ever happened. So I am thinking one of the safety switches must be the problem or blown starter fuse at the starter. Fuse checked out good. I grab a test lead with alligator clips and jump out the starter solenoid while pushing in on the clutch and key in the run position. Nothing. I then tie the seat down as to depress both seat switches. I jump the solenoid again and it starts. As soon as I untie the seat and 2 seconds later it shuts down. The PTO is disengaged if your wondering. So I jump out both seat switches and still the same thing. I am now wondering if the clutch safety switch is the culprit. It seems to be closing the switch externally. Tough to get to the boot to pull it up far enough and jump it out. This is where I stopped for now. At least I got it back in the barn. The PTO safety switch could also be the issue. I looked down in that area and there are two. Thoughts?
sounds similar to a couple of problems I had on my b2710 with the hst pedal switch. firstly the switch actuation mechanism was worn so would not activate the switch in the "pedal neutral" position. secondly the switch adjustment screw came loose and allowed the switch to move out of alignment with the actuation mechanism. lying on my back under the hst pedal side allowed me to see the operation of the switch to work out what was happening. Also the "pedal neutral" position on mine was in such a small envelope of operation that sometimes it was necessary to turn the key to the start position and slowly move the hst pedal to find the neutral start position.
 

GreensvilleJay

Well-known member

Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
9,368
3,801
113
Greensville,Ontario,Canada
re bypass
he may mean bypass the starter relay. from the wiring I saw, power from ign sw goes to one end of a 'starter relay' and the 3 safety switches are in series from the relay to ground. You can 'bypass' them simply by jumping +12 on starter to the starter solenoid contact...
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
5,075
2,310
113
North of Pittsburgh PA
re bypass
he may mean bypass the starter relay. from the wiring I saw, power from ign sw goes to one end of a 'starter relay' and the 3 safety switches are in series from the relay to ground. You can 'bypass' them simply by jumping +12 on starter to the starter solenoid contact...
That is probably what the OP meant. Looks like there is no start relay on the B7800, just an output from the OPC to the starter solenoid, via a switch on the clutch pedal. Did not look further to see if there are other permissive inputs to the OPC. Certainly might be, as I believe the B7800 has a operator presence switch on the seat.
 

dmoore

Member

Equipment
2006 B7800, RC72-BA 72" mid mount mower, RB 1672 72" rear blade
Feb 8, 2010
78
6
8
62
Exmore,Virginia
re bypass
he may mean bypass the starter relay. from the wiring I saw, power from ign sw goes to one end of a 'starter relay' and the 3 safety switches are in series from the relay to ground. You can 'bypass' them simply by jumping +12 on starter to the starter solenoid contact...
precisely
 

dmoore

Member

Equipment
2006 B7800, RC72-BA 72" mid mount mower, RB 1672 72" rear blade
Feb 8, 2010
78
6
8
62
Exmore,Virginia
That is probably what the OP meant. Looks like there is no start relay on the B7800, just an output from the OPC to the starter solenoid, via a switch on the clutch pedal. Did not look further to see if there are other permissive inputs to the OPC. Certainly might be, as I believe the B7800 has a operator presence switch on the seat.
Correct, a run switch & a start switch. Both jumped out they are not the issue. I have not had time to jump out the hydro & PTO switches just yet. I am thinking one of them is the problem. Thank you for the responses. I am ordering a FSM tomorrow. After 16 years I guess I will need one.
 
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Mark_BX25D

Well-known member

Equipment
Bx25D
Jul 19, 2020
1,611
1,140
113
Virginia
Now that you've ruled out typical problems using logic you should simply start buying new parts for your immaculate tractor stored in the climate controlled building. Use the following order:
1. replace starter solenoid
2. replace key switch
3. replace starter
4. replace fuses
No. This is just firing the parts cannon. It's the most expensive and frustrating way to fix a problem, and usually takes the longest.

There is a lot more troubleshooting to be done. Getting those wiring diagrams is the first step.
 
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