i1046 - Cuts & Mulches Poorly / Deck Noise

Hello!

I came into a good deal (family) on an i1046 with under 50 hours on it couple of years ago for $500 so I jumped on it.

A problem I've had since the onset is it does not seem to mulch or cut well below the highest setting. Generally this is OK as I like to cut around 4in for a bulk of the growing season. But when things are growing fast in spring and fall I like to cut a little lower so im not out every two days and when I attempt to go anywhere below that highest deck height it makes almost like a grinding noise intermittently and mulches very poorly.

Now I always TRY to follow the 1/3rd rule which means with my grass every 3-4 days and I wait for dry grass when feasible, my grass is VERY thick for the most part. Even if I cut high and then go over it a second time lower the noise is still present and the cut is poor.

I have replaced the belt and greased the zerks (the middle spindle doesnt have a zerk), I also clean the deck every so often (not with the washout port).

Ideas I am thinking about -

Take off deck and see if spindles are noisy when free spinning, if so replace bearings or spindles altogether
Spray deck with non-stick
Replace deck springs
Get very particular (learn) and level the deck (although I think its pretty well level)

Has anyone ever experienced something similar? Anything else I should check?

Thanks for your help!

Obligatory Lawn Pic

How are the blades? They need to be sharp and sharpened often if you're going to be mulching since they're cutting and re-cutting the same grass over and over. And the deck needs to be kept clean, not just every so often. Could the noise you're hearing be clods of grass stuck to the deck falling down and hitting the blades?

middle spindle is possible culprit with no zerk fitting

https://www.cubcadetpartsdistributor.com/