diff --git a/libraries/AP_HAL/Scheduler.h b/libraries/AP_HAL/Scheduler.h
index 92ea71ed74..fa144b8f49 100644
--- a/libraries/AP_HAL/Scheduler.h
+++ b/libraries/AP_HAL/Scheduler.h
@@ -11,7 +11,7 @@ class AP_HAL::Scheduler {
 public:
     Scheduler() {}
     virtual void     init(void* implspecific) = 0;
-    virtual void     delay(uint32_t ms) = 0;
+    virtual void     delay(uint16_t ms) = 0;
     virtual uint32_t millis() = 0;
     virtual uint32_t micros() = 0;
     virtual void     delay_microseconds(uint16_t us) = 0;
diff --git a/libraries/AP_HAL_AVR/Scheduler.cpp b/libraries/AP_HAL_AVR/Scheduler.cpp
index 6381a50463..d811f6fdea 100644
--- a/libraries/AP_HAL_AVR/Scheduler.cpp
+++ b/libraries/AP_HAL_AVR/Scheduler.cpp
@@ -64,7 +64,7 @@ void AVRScheduler::delay_microseconds(uint16_t us) {
     _timer.delay_microseconds(us);
 }
 
-void AVRScheduler::delay(uint32_t ms)
+void AVRScheduler::delay(uint16_t ms)
 {
 	uint32_t start = _timer.micros();
     
diff --git a/libraries/AP_HAL_AVR/Scheduler.h b/libraries/AP_HAL_AVR/Scheduler.h
index f557ee83c7..f03742f813 100644
--- a/libraries/AP_HAL_AVR/Scheduler.h
+++ b/libraries/AP_HAL_AVR/Scheduler.h
@@ -25,7 +25,7 @@ public:
     /* init: implementation-specific void* argument expected to be an
      * AP_HAL_AVR::ISRRegistry*. */
     void     init(void *isrregistry);
-    void     delay(uint32_t ms);
+    void     delay(uint16_t ms);
     uint32_t millis();
     uint32_t micros();
     void     delay_microseconds(uint16_t us);
diff --git a/libraries/AP_HAL_AVR_SITL/Scheduler.cpp b/libraries/AP_HAL_AVR_SITL/Scheduler.cpp
index f273ca8423..b3a8adaa99 100644
--- a/libraries/AP_HAL_AVR_SITL/Scheduler.cpp
+++ b/libraries/AP_HAL_AVR_SITL/Scheduler.cpp
@@ -60,7 +60,7 @@ void SITLScheduler::delay_microseconds(uint16_t usec)
 	}
 }
 
-void SITLScheduler::delay(uint32_t ms)
+void SITLScheduler::delay(uint16_t ms)
 {
 	uint32_t start = micros();
     
diff --git a/libraries/AP_HAL_AVR_SITL/Scheduler.h b/libraries/AP_HAL_AVR_SITL/Scheduler.h
index 755e513ed9..5ae4d84792 100644
--- a/libraries/AP_HAL_AVR_SITL/Scheduler.h
+++ b/libraries/AP_HAL_AVR_SITL/Scheduler.h
@@ -16,7 +16,7 @@ public:
     /* AP_HAL::Scheduler methods */
 
     void     init(void *unused);
-    void     delay(uint32_t ms);
+    void     delay(uint16_t ms);
     uint32_t millis();
     uint32_t micros();
     void     delay_microseconds(uint16_t us);
diff --git a/libraries/AP_HAL_Empty/Scheduler.cpp b/libraries/AP_HAL_Empty/Scheduler.cpp
index 0698a3b3de..de4de5843d 100644
--- a/libraries/AP_HAL_Empty/Scheduler.cpp
+++ b/libraries/AP_HAL_Empty/Scheduler.cpp
@@ -11,7 +11,7 @@ EmptyScheduler::EmptyScheduler()
 void EmptyScheduler::init(void* machtnichts)
 {}
 
-void EmptyScheduler::delay(uint32_t ms)
+void EmptyScheduler::delay(uint16_t ms)
 {}
 
 uint32_t EmptyScheduler::millis() {
diff --git a/libraries/AP_HAL_Empty/Scheduler.h b/libraries/AP_HAL_Empty/Scheduler.h
index e64a4d7c52..e624291d5b 100644
--- a/libraries/AP_HAL_Empty/Scheduler.h
+++ b/libraries/AP_HAL_Empty/Scheduler.h
@@ -8,7 +8,7 @@ class Empty::EmptyScheduler : public AP_HAL::Scheduler {
 public:
     EmptyScheduler();
     void     init(void* machtnichts);
-    void     delay(uint32_t ms);
+    void     delay(uint16_t ms);
     uint32_t millis();
     uint32_t micros();
     void     delay_microseconds(uint16_t us);