B7200 HST Decompression Lever Questions

[NoJacketRequired]

Our "new to us" B7200 HST has been doing a great job blowing snow, and it seems like the snow is never going to end... Haven't tried to start it yet when very cold - all starts have been at temperatures of -5C and above. In reading the Operator's Manual I see a recommendation to use the decompression lever for cold starts.

The Bowden cable for the decompression lever is fine - it moves quite freely when disconnected from the lever on the cylinder head. The decompression lever itself is very, very sticky, as in needing to be tapped lightly with a mallet to move it. I want to cycle the lever back and forth a few times to free it up before reconnecting the cable.

Here's my question. How do I know when I have reached the travel limits of the lever, both in the "decompress" direction and in the "restore compression" direction? I'm quite concerned about going too far in the decompression direction, and not getting it returned far enough to the "restore compression" position.

On a similar note, is there a better way to free up this decompression lever? The tractor has been used only in the summer for the past 8 years, so it's been at least that many years since the decompression lever has been used.

Thanks for any guidance you might be able to provide.

Mark.

 

[D2Cat]

Spray some of your favorite rust solvent like PB Blaster on the pivot point right at the valve cover. Move the lever until it frees up. Then reconnect the cable end.

If you need more details of what/how the decompression lever works under the valve cover you can look at the parts list and see it. Go here. Slide down and click the "accept" box, then go down and list you model of tractor.

http://www.kubota.com/part/partsList.aspx

 

[NoJacketRequired]

Thanks, D2. I'm struggling to make the parts list search tool work, keep getting timeouts. Will have to find a way to get the parts book so I can see if that decompression lever has detents or mechanical stops to limit its travel.

Given the size of the return spring, it's obvious this lever should move rather freely. Time for some more lubrication and flexing of the lever with gentle persuasion!

 

[torch]

Since you are in Canada, you might have better luck with the Canadian parts site:

https://kubota.ca/en/parts-services/parts-catalogue/parts-finder

 

[fatjay]

Please post back on how successful that is. Mine is a struggle to move by hand on my b8200. I haven't needed it yet, and hope I don't, but I'd like to be able to should I need to.

 

[Tooljunkie]

Took mine a while, lubed and cycled every time i used machine. Lever on injection pump as well. Had a brake hanging up too. All got sprayed and moved repeatedly until they submitted to my will.A year later and all still behave.

 

[NoJacketRequired]

Thanks for this feedback, Tooljunkie. Just out of curiosity, do you remember if the decompression lever has hard limits on its angle of rotation? I don't want to end up bending something because mine is quite stiff indeed.

 

[D2Cat]

The return spring should be totally relaxed when compression release is closed. Once you get the lever free to move you'll see it's limitations. At the dash your knob will pull out 1 1/2" or so.

When the CR is open your engine should turn over like the glow plugs were removed!

 

[sinisterbiker]

Would it be possible for someone to post a pic of that setup, i have a b7100 with a hole in the dash for it but no cable, just the lever on the head. Ty

Sent from my SM-G930T using Tapatalk

 

[Tooljunkie]

If i recall i didnt move it all that much at first ,as it loosened it freed up the whole stroke of lever. Then you will feel the limit.

 

[D2Cat]

Sinisterbiker, I think your B7100 has a plug in the dash because there was no compression release on that tractor. If you look at the front of the valve cover you will see the part where the breather pipe goes, that's all that should be there.

 

[sinisterbiker]

Sinisterbiker, I think your B7100 has a plug in the dash because there was no compression release on that tractor. If you look at the front of the valve cover you will see the part where the breather pipe goes, that's all that should be there.

Ok, this is whats there D2 cat

Sent from my SM-G930T using Tapatalk

 

[D2Cat]

Maybe your tractor was manufactured as they were finishing up the old style valve comers.

I checked my tractor today, and it's not there.

 

[torch]

Mine was made in 1994. It has the hole with the black plug in the dash like yours, but the hole is not labelled and there is no lever on the head. D2cat may be on to something -- yours might have been made right at the change. Or maybe a previous owner "upgraded" to the newer specification.

 

[JunkyardDog]

I have an L245 with a "seriously" stuck Decompression Release Lever. I have tried PB Blaster and it is still stuck tight. There is no movement at all. There is too little shaft external to the cover to get a grip on. And yes, I did already remove the lock screw.

I really would like to avoid heating up the cover as it is aluminum and will warp easily. Has anyone had any other success getting it unstuck when it is stuck solid? How did you do it?

I hate to go so far as to make a custom socket (read as get it made) to fit over the end and use an impact on it. Cost aside, making a tool to use once does not seem practical.

 

[torch]

I really would like to avoid heating up the cover as it is aluminum and will warp easily.

Heat the steel, not the aluminium. Let the heat soak into the aluminium for a couple of minutes, then apply ice to the steel and penetrating oil to the junction. You may have to repeat a few times, but eventually the heat/cool cycles should wick the penetrating oil into the joint.

 

[JunkyardDog]

Finally! It came loose. I pulled out the propane torch. It took a while to find the lighter that was right in front of me. Found a small container and filled it with ice. I tried it one more time and it moved just a smidgen. Intimidation works! I didn't even use the fire and ice.

I forgot to take pictures as I was losing daylight. But, I cleaned it up and re-assembled. All but the actual decompress adjustments are done. I'll get to that when more light allows.

Thanks!