Lazer HP ?

[northeast]

Yesterday while mowing with a 2000 lazer hp 48"deck,20hp kohler
and ultra vac,was cutting up hill full speed and heard grrr sound
backed off a bit on levers and came out of it,was wondering if it could be wheel motors slipping or main blade belt slipping?it is the origanal belt with about 300 hrs on it.Anyone else experience this ?
mowed same property all last season without this problem.anyhelp here would be greatfull. Thanks Nick

[Cutter1]

My hp did this last year. Did it start to shake?? When you backed off the sticks, did it stop?? What it was for me was the tension spring underneath for the hydros. Its too small!! When you are going up hills it slips a little and makes that noise. They replaced it with a spring 1 1/2 times bigger and it has never done it since.

[65hoss]

If it starts to shake and is not running as fast it is probably the hydro fluid to low and its sucking some air. I had that happen in the fall, dealer added some fluid and problem solved. If you look in the little tank, the fluid should be up just over the divider in the middle.