Raptor SD Clutch Engagement Sudders Machine Violently And Almost Kills The Engine.

[mhavanti]

I have a Raptor SD60 that is doing a great job thus far. However, that isn't very long since it only has almost 3 hours on it.

During the engagement of the electric clutch, the mower shakes violently to the point of almost killing the motor. Most of which I realize is the rapid pull of the blades on the engine as though brakes were applied. However, how violent is yours is my question.

 

[Kremeneon]

Mine is pretty violent. The clutch engages quite hard/positively, not really allowing the engine any time to get things moving smoothly, just BAM! blades. The heavier gator blades I have amplify the engagement shudder also. The idea is though, since the engagement is so positive, that you only run the engine up enough to not stall when the clutch engages so as to impose the least shock on components and wear on the clutch. Run the engine all the way up and it will handle it better, but it is a helluva lot more shock on everything.

 

[mhavanti]

Mine is pretty violent. The clutch engages quite hard/positively, not really allowing the engine any time to get things moving smoothly, just BAM! blades. The heavier gator blades I have amplify the engagement shudder also. The idea is though, since the engagement is so positive, that you only run the engine up enough to not stall when the clutch engages so as to impose the least shock on components and wear on the clutch. Run the engine all the way up and it will handle it better, but it is a helluva lot more shock on everything.

I've engaged the clutch both at full throttle and low throttle to find the least amount of shock on the belt and the crankshaft and rod bearings. It is about equal other than the lower rpm doesn't seem to want to flip the mower. lol

 

[katit]

Read manual. Engage at 3/4, disengage at 1/2. I engage at little over 1/2 where engine doesn't almost die and there is no big shock. Works good.

 

[Kremeneon]

Read manual. Engage at 3/4, disengage at 1/2. I engage at little over 1/2 where engine doesn't almost die and there is no big shock. Works good.

Yep, that 's what the little [* and [ * marks are on the throttle slider. PTO engage about 3/4 and PTO disengage at idle ( I think its idle, maybe a little higher up). I'd like to note there is a brake on the clutch -so when you disengage, it actively stops the blades and holds them stopped, they don't just freewheel to a stop. which is why you want to turn off the blades at lower RPM. To save wear on the brake side of the clutch also.

This is also why you can't just easily hand turn the blades with engine off (and key out), the clutch is still braking the belt.

 

[katit]

Also, disengaging at high speed might cause it to throw a belt, be careful..