diff --git a/src/glkapi/glkapi.ts b/src/glkapi/glkapi.ts
index 463d8c0..95783fb 100644
--- a/src/glkapi/glkapi.ts
+++ b/src/glkapi/glkapi.ts
@@ -248,7 +248,7 @@ export class AsyncGlk implements Interface.GlkApi {
         // Timer
         const timer = this.timer
         if (timer.last_interval !== timer.interval) {
-            state.timer = timer.interval || null
+            state.timer = timer.interval
             timer.last_interval = timer.interval
         }
 
diff --git a/src/glkote/common/glkote.ts b/src/glkote/common/glkote.ts
index 3734759..6da5405 100644
--- a/src/glkote/common/glkote.ts
+++ b/src/glkote/common/glkote.ts
@@ -296,7 +296,7 @@ export abstract class GlkOteBase implements GlkOte {
     }
 
     protected ontimer() {
-        if (!this.disabled) {
+        if (!this.disabled && this.timer) {
             this.send_event({type: 'timer'})
         }
     }