Hello. My old (1996 vintage) Scag SSZ CV22 with a 61" deck won't stay running when I engage the mower deck. Here are the symptoms:
Starts and runs OK, but doesn't want to run with the choke on. I need to push the choke in right away to keep it running.
Once running, applying full choke kills the engine
When I engage the mower deck the main idler shakes quite a lot and it kills the engine.
If I apply part choke I can get it to stay running with the deck engaged, but it won't run full speed.
With the belts removed, engaging the deck switch has almost no effect on the engine.
With the belts removed all 3 blades turn freely by hand with no discernible difference in friction and no noises.
Each idler turns very freely but each has a fair bit of vertical play, especially the main idler.
Belts were replaced last season when the mower was thowing the main belt while mowing. After replacing the belts it ran fine for the rest of the season.
Here's a video of the belts when I try to engage the deck:
I'm a pretty handy DIY guy, but not sure where to go from here. What should I check next?