867 engine straining when going uphill with blades engaged

[ClevelandBrown 47]

My 867 ran strong for the first thirty minutes of grass cutting.  Then - all of a sudden - it started losing a little power when going uphill with blades engaged.  It didn't shut-off but was straining mildly (which it's never done even on the same hill).  The problem got worse as I kept going to the point that even a gentle rise would strain the engine.  I quit when it sounded like the engine was getting close to cutting out.  

 

The straining immediately stopped when I pressed the pedal to disengage the blades.  With blades disengaged, the engine didn't strain at all climbing the same (or steeper) hills.

 

Any suggestions about where to start?  The decking was greased an hour or two ago and everything seems to turn freely.  It seems to have full power when going on flat land.

 

Regards,

Sam

[Darb1964 1,119]

Did you check the deck to see if something got wrapped up in the blades.

[oliver2-44 10,715]

Also check the spring loaded deck tension pulley to be free.

[peter lena 9,273]

agree with above, i would drop the deck and check for something wound up in blades . also take time to scrape it out , mabey light file blade edges, obviously  , something pulling it down , can you move the pto drive belt easily by hand ?  pto pulleys spin easily ? pete

[Stepney 2,354]

I echo all of the above for a first case.

If not, Id look for other slightly less obvious things. Plugged up tank vent, timing and spark up to snuff,  weak fuel pump, is it running hot? 

[oilwell1415 563]

Is the governor linkage binding up?

[ClevelandBrown 47]

Y’all are the best.  I checked for something binding the blades but there wasn’t anything there.  So, I oiled the tension pulley that seemed a bit sluggish as well as the throttle/governor linkage.  No problems after that!  
 

Thanks for your help!  This community is teaching me so much about how to care for these beautiful old machines!

 

Regards,

Sam