Troy built 33" walk behind blades disengage

luxeder

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I have a 15 year old walk behind Troy Built with twin blades (33") cut.

from time to time when using the machine, the blades will stop turning.
it can happen every few minutes or once or twice per mow.

Has anyone else had this issue? is there an adjustment that a novice can make?

It's getting very frustrating to mow, when you have the re-engage the blade every few minutes....

thank you
 
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I have the same problem on my 34044 (same model but recoil start). The mower will continue moving forward but the blades will be disengaged. Looking on page 5 of the Parts Catalog (for Models 34041 and 34044), Ref#41 and 44 are the Interlock Cam and Interlock Latch. I think that they are what keep the blade engagement lever from disengaging until the operator presence control is released. I will try to figure out why the cam and latch are disengaging.
 
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SRTsFZ6's above post has the parts catalog page on line. The page that shows the interlock cam and the interlock latch (Ref. #'s 41 and 44) is actually here: https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/troy-bilt/legacy/wide-cut-mowers/34044-8-5hp-std-33-cut-s-n-01/drive-assembly

Yesterday I spent some time looking at the mechanism from the outside. I cut some grass as well. The disengagement seems to be random. Bouncing or rapidly moving the mower side to side does not make the blades disengage. The interlock latch falls into place by gravity. Apparently, it is held in place by the tension from the idler pulley extension spring. I'll have to double check, but I think that the blades can be disconnected by pushing the engagement lever forward/down. I don't think this is advisable though. The correct way to release the blades is to release the operator presence control. I think that this rotates a part which lifts the interlocking latch up. I expect that I'll have to disassemble the mechanism.

I'd like to raise the mower up so that I can more easily work under it. I wonder if anyone has any experience in raising the mower and setting it on something.
 

(Account Closed)

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Looks like those two parts have an "edge/lip" in the middle of them that likely lock them together when your underway. (hard to tell W/O seeing the machine up close).

If those edges are worn, (I'm guesstamating now), that may be allowing the disengagement of the blades..

Kinda like worn "dogs" in a manual transmission. The dog jumps out of gear due to wear, being worn to an angle, etc(should be square or better yet "back cut"..
 
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View attachment 42801 I took off the control shaft assembly:
  1. Disconnect 3 operator-actuated rods from the bell cranks by removing cotter pins and washers.
  2. Disconnect the 3 controlled rods from the 3 bell cranks.
  3. Remove the 4 bolts from the top of the deck thereby freeing the assembly.
  4. Extract the assembly from under the deck by moving it to the left and rotating and twisting it as necessary.
From there it took a bit of imagination and thinking to understand the logic of this clever mechanism. The interlocking cam and latch appear to be in good shape and the mechanism appears capable of functioning normally. Basically, in order for the blades to disengage, the operator presence lever (which also controls the transmission brake) must be released. The blades are disconnecting randomly and often. I will reassemble and check the adjustment and function of the operator presence control rod (and probably the brake).
 
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Yesterday I tried mowing. The blades disengaged more frequently the more I mowed. There is a gap of about 1/16" between the release dowel and the latch when the operator presence control lever is held against the handle. The end of the lever rise 1½" above the handle before it will disengage the latch from the cam. The operator presence control lever was still held against the handle when the blades disengaged. The next time that there is a dry day, I want to mow until the blades disengage. Then, without removing my hand from the operator presence control, I'll turn off the engine, and then feel to see what position the latch, cam and release dowel are in. Perhaps I'll tie the levers in place with a piece of rope. Maybe the inside of the cam is worn. The cam must have a fixed connection to the shaft.

If the operator isn't present, the large tension spring will loosen the belt and engage the blade brake. The tension of the spring also keeps the cam locked to the latch.

The compression springs on the ends of the two connecting rods make connections that support tension only. Motion cannot be transmitted by compression or pushing on the road.

2019-02-12 14.16.32.jpg2019-02-12 14.16.06.jpg2019-02-12 13.39.57.jpg
 
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I found the solution. Adjust the Operator Presence Control rod to be shorter. This is adjustable but is not covered in the owners manual. The interlocking latch disengagement dowel was too close to the latch.

  1. Remove the cotter pin from the link end.
  2. Remove the link end and washer from the bell crank.
  3. Loosen the lock nut.
  4. Turn the link end up the control rod (I turned mine 2 full turns).
  5. Insert the washer on the link end and the link end into the bell crank.
  6. Install the cotter pin.
  7. Tighten the lock nut.

If the blades still pop out, repeat the procedure.

Here is an illustration of the parts: Troy linkage.jpg
 

BlazNT

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I found the solution. Adjust the Operator Presence Control rod to be shorter. This is adjustable but is not covered in the owners manual. The interlocking latch disengagement dowel was too close to the latch.

  1. Remove the cotter pin from the link end.
  2. Remove the link end and washer from the bell crank.
  3. Loosen the lock nut.
  4. Turn the link end up the control rod (I turned mine 2 full turns).
  5. Insert the washer on the link end and the link end into the bell crank.
  6. Install the cotter pin.
  7. Tighten the lock nut.

If the blades still pop out, repeat the procedure.

Here is an illustration of the parts: View attachment 42905

Thank you for coming back and posting the fix. It will help someone else with this problem.
 
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