Automatic Compression Release

[dkamp]

I have a Craftsman 917.203900 with a Briggs Engine 44R677-0021-G1 (2 cyl,22HP)
Sometimes it is HARD to start unless I roll the engine past compression cycle. (It acts like a low or dead Battery) I assumed it has an issue with ACR.
I just finished adjusting the Valves the intake on both were very loose. Now all is good with that adjustment.
One Youtube video showed to roll the engine and watch for the rocker to make a slight dip when closing.
I watched very closely and do not see any form of rocker arm dip. So I wanted to verify, does my engine actually have the ACR?
if it does.......Do I need to replace the 4 lobed Cam, ( PN 797242) or something else?
David

 

[ILENGINE]

Pictures of that cam do show an ACR. Don't see many failures with the twin cams but could be possible. So if the bump isn't happening on the valves then there is a good chance that the ACR is broken. So the only option would be to replace the camshaft.

 

[StarTech]

Ran into this recently helping someone on another forum. Depending when the engine was it might still have the non ACR camshaft. Briggs did supersede it to new the newer ACR camshaft and replacements will be the ACR style camshaft.

The old PN 792555 was superseded to 797242 version.

 

[dkamp]

I do see a Mfr date of Jan 2014 on the engine, if that helps nail down if I actually have ACR or not.
Should I go thru the trouble to add the newer Cam with the ACR? or live with the occasional Roll the engine manually to get over the compression stroke so it has momentum to spin and start up?

 

[Craftsman Garage]

I have only seen ACRs on Vtwins newer than 2018 I think. I know for a fact that yours does NOT have it. These Briggs Vtwins always have high compression. I say replace starter and battery and clean the Battery cable ends and the starter mounting surface with a wire brush.

 

[Craftsman Garage]

Hey... I realized after I looked up your model No. That I have the exact same tractor! I rebuilt the same engine last year and it didn't have a compression release so there's your answer.

 

[dkamp]

Hey Craftsman Garage, thank you for your information. Yesterday I did buy a new 320 CCA Battery and cleaned all connections on Battery and Starter. I had to wait for my Gasket maker stuff 24 hrs to dry after sealing the Valve covers. I will test how it cranks today.
Another subject..
I do have a RS8007340774 Transaxle made by General Transmission (GT87100 plastic case) I had issues with. after replacing the variation Control assy it fixed my Issues, but if you know of tweaks to that transaxle, please direct me to them. it takes considerable pedal push to Reverse.
Again, thanks for verifying the ACR.

 

[Craftsman Garage]

Yeah, I know a lot about that transmission. I actually just finished swapping my plastic transmission for metal hydrostatic transmission. Alright, so I was having trouble with the pedals sticking, like it would go forward but when I press reverse, it was rock hard. It also would go into neutral when I let off the pedal which was extremely dangerous. What I did was I took every screw and spring off the top of that transmission until there was just the driveshaft. Then there is a big plastic piece with a small oval-like shape on the right, it is not a complete oval but I figured out that the issue with the pedal sticking was that, so I sanded it down until it was a smoother oval shape. Then I found a official General Transmissions video on YouTube showing how to disassemble and reassemble the transmission. I followed that guide because I wanted the linkage to be factory. I also replaced the CVT belt with an an oem one because yours will inevitably fail. Now this transmission is on my Craftsman Professional T7400 and working great. Eventually I will get a better transmission for it, like a k57 or K66ELD, but for now it is working fine. I haven't had any problems. OH, and don't use any grease! Wash all the old grease off if there is any, and assemble it completely dry. I found that adding grease would attract dust and other Junk, and speed up wear. Good Luck buddy, and feel free to ask me whatever other questions you have.

 

[Auto Doc's]

Is it cranking properly after the valve adjustment was done? I do not think these early ones had ACR.

 

[dkamp]

it is working well after the valve adjustment. I also found why it was surging while giving it some needed attention.
I noticed that where the carb attaches to the Plastic Intake manifold, there was a gap from the plastic being warped. I little Gasket maker sealed it until I get another intake manifold.