Mechanos
Veteran Member
I'm curious about this compression release. I am not familiar with this device and was just wondering if my 955 has one.
850 Won't Start
- Thread starter Republic of Texas
- Start date
- Views: 13530
Mechanos
Veteran Member
What engine is in the 850? Is it covered in the CTM-3 manual?
OP
Republic of Texas
Bronze Member
The engine in the 850 is the 3T80J. I looked through that manual and I did not see this engine mentioned.
OP
Republic of Texas
Bronze Member
The "compression release" is the only name I know to give it. I'm not sure what it's actually called, and I'm pretty sure that due to my inexperience, I am butchering the name and the intent of this device.
I will add an image in an hour or so.
OP
Republic of Texas
Bronze Member
If I am missing something, please let me know. All information will be greatly received and appreciated.
OP
Republic of Texas
Bronze Member
Video Added
Attempted to start. Almost started. Decided to check coolant level after this attempt. Radiator had extreme pressure when cap was released. Coolant found to be low.
Finally got it to start. Here's a video of what appears to be coolant coming out of the exhaust.
Video:
John Deere 850 Head Gasket - YouTube
I feel more confident that it's a head gasket, but not 100% until I see it. Should I take the head in and have it checked regardless? While I have the head off, what else should I look for?
Thank y'all so much for the help. Much appreciated.
Attempted to start. Almost started. Decided to check coolant level after this attempt. Radiator had extreme pressure when cap was released. Coolant found to be low.
Finally got it to start. Here's a video of what appears to be coolant coming out of the exhaust.
Video:
John Deere 850 Head Gasket - YouTube
I feel more confident that it's a head gasket, but not 100% until I see it. Should I take the head in and have it checked regardless? While I have the head off, what else should I look for?
Thank y'all so much for the help. Much appreciated.
AGGIE00
Gold Member
- Joined
- May 9, 2010
- Messages
- 449
That little engine will take more abuse than most can dish out. Definitely check the head for cracks and warp, but from my experience a head gasket is all you will need. While it is off check the water pump and replace the thermostat. Ask Deere for the torque specs and pattern. It's pretty simple with a torque wrench.
The compression release is a slide rail on top of the head that holds the exhaust valves open. This is used for cold starting so the engine can be spun freely and started by simply disengaging the realease while it is spinning.
The compression release is a slide rail on top of the head that holds the exhaust valves open. This is used for cold starting so the engine can be spun freely and started by simply disengaging the realease while it is spinning.
Mechanos
Veteran Member
Yes... I sure would. I think I'd even pony up to have it magnafluxed.
eastshores
New member
Joined just to share my recent experience since this thread was helpful. I have a John Deere 850 that was running fine.. I don't run it too often but ran it the day before and then came out and it wouldn't turn over.. didn't really do anything. I figured OK apparently the alternator isn't charging the battery and hooked up a charger. Next day with battery at 100% the same thing.
This set forth a series of tests. I first checked the cable connections to the battery. They were basically fine.. I had recently put a new battery on it and used dialectic grease so there wasn't any corrosion. Tightened just in case and still nothing. I thought ok maybe a safety switch.. so I wiggled all the levels and rocked it back and forth etc. with nothing. That's when I decided maybe the ignition switch went bad. I pulled the switch out, and it's a little confusing. If anyone else comes across this.. there are two wires that you should concern yourself with.. the thick white wire is a hot wire that comes off the starter to the ignition switch. There's a black wire with a white strip, that returns to the solenoid on the starter and this is where you want to check that when you turn the switch, that you register 12v. In my case it was fine and therefore I ruled out the safety switches as well as the ignition switch.
So my mind thought.. OK .. my solenoid has gone out since it wouldn't even click. I pulled the starter and took it down to Autozone. They were able to hook it up to their test machine and it fired right up. This was a big help because that isolated the issue to having a bad ground as some of the posters on here had advised. I bought a new ground cable and headed home. Installed the starter. Replaced the ground cable and when I was loosening the bolt in the frame for the ground cable I noticed it was basically stripped. It was tight.. but the threads were mashed flat. I found another bolt laying around and grabbed a nut and was able to secure the cable using the bolt with the nut to lock it down. Turned the key and she fired right up!
Thanks to all of the posters before me, it helped a lot. My father passed away last year and although he tought me a lot it is always nice to hear the voice of experience when mine is no longer here.
This set forth a series of tests. I first checked the cable connections to the battery. They were basically fine.. I had recently put a new battery on it and used dialectic grease so there wasn't any corrosion. Tightened just in case and still nothing. I thought ok maybe a safety switch.. so I wiggled all the levels and rocked it back and forth etc. with nothing. That's when I decided maybe the ignition switch went bad. I pulled the switch out, and it's a little confusing. If anyone else comes across this.. there are two wires that you should concern yourself with.. the thick white wire is a hot wire that comes off the starter to the ignition switch. There's a black wire with a white strip, that returns to the solenoid on the starter and this is where you want to check that when you turn the switch, that you register 12v. In my case it was fine and therefore I ruled out the safety switches as well as the ignition switch.
So my mind thought.. OK .. my solenoid has gone out since it wouldn't even click. I pulled the starter and took it down to Autozone. They were able to hook it up to their test machine and it fired right up. This was a big help because that isolated the issue to having a bad ground as some of the posters on here had advised. I bought a new ground cable and headed home. Installed the starter. Replaced the ground cable and when I was loosening the bolt in the frame for the ground cable I noticed it was basically stripped. It was tight.. but the threads were mashed flat. I found another bolt laying around and grabbed a nut and was able to secure the cable using the bolt with the nut to lock it down. Turned the key and she fired right up!
Thanks to all of the posters before me, it helped a lot. My father passed away last year and although he tought me a lot it is always nice to hear the voice of experience when mine is no longer here.
