diff --git a/src/magpie-transformer.ts b/src/magpie-transformer.ts
index f7b8609a4dbc86789fc0f39f0a12e3a994caff38..a7f0accb779a5d89d1493ac7d1bc27872efd6559 100644
--- a/src/magpie-transformer.ts
+++ b/src/magpie-transformer.ts
@@ -39,7 +39,8 @@ class MagpieTransformer extends Transform {
     /**
      * Timeout for a server
      */
-    private serverTimeout = 30 * 1000;
+    private readonly serverTimeout = 30 * 1000;
+
     /**
      * Logger
      */
@@ -71,6 +72,7 @@ class MagpieTransformer extends Transform {
         this.delay = options.delay || 200;
         this.concurrent = options.concurrent || 10;
         this.requestOptions = options.requestOptions || {};
+        this.serverTimeout = options.serverTimeout || 30 * 1000;
     }
 
     /**
@@ -97,30 +99,19 @@ class MagpieTransformer extends Transform {
 
         this.pending++;
         setTimeout(() => {
-            let foundServer = false;
-            // if the server is not reacting wait for a timeout and then call the callback
-            setTimeout(() => {
-                this.pending--;
-                if (!foundServer) {
-                    this.logger.warn('Too fast. ServerTimeout triggered');
-                    this.emit('free');
-                }
-            }, this.serverTimeout);
-
-            const options = {...this.requestOptions, ...{url: data.url}};
+            const options = {...this.requestOptions, ...{url: data.url, timeout: this.serverTimeout}};
             MagpieTransformer._request(options,  (err, res, _) => {
                 this.pending--;
-
-                foundServer = true;
                 if (err) {
-                    this.logger.error(err, data.url);
-                    this.push(null);
+                    this.logger.warn(err, data.url);
+                    this.emit('error', err);
+                    return this.emit('free')
                 }
 
                 const doc = new Document(data.url, res);
                 this.logger.info('Success', data.url);
                 this.push(doc);
-                this.emit('free')
+                return this.emit('free')
             });
         }, this.delay);
         callback();
@@ -129,7 +120,7 @@ class MagpieTransformer extends Transform {
     // Wrap it for easier mocking
     private static _request(opts, done) {
         // All options forwarded to request()
-        request(opts, done);
+        return request(opts, done);
     }
 
     // @ts-ignore
diff --git a/test/magpie-transformer.spec.ts b/test/magpie-transformer.spec.ts
index 8539062f642bcc6261a4b674e0f7190426164e0b..2ca8604aba22e6c2ec991e3336f345f570f91990 100644
--- a/test/magpie-transformer.spec.ts
+++ b/test/magpie-transformer.spec.ts
@@ -20,7 +20,11 @@ describe('Test magpie-transformer', () => {
         chai.should();
         // start a test server to fetch data from
         const requestHandler = (request, response) => {
-            response.end('ok')
+            if(request.url === '/timeout') {
+                setTimeout(() => response.end('ok'), 1000)
+            } else {
+                response.end('ok')
+            }
         };
         server = http.createServer(requestHandler);
         server.listen(3000, (err) => {
@@ -58,7 +62,7 @@ describe('Test magpie-transformer', () => {
         const options = {
             objectMode: true,
             logger: coreMock.getLogger(),
-            delay: 2000,
+            delay: 200,
             concurrent: 1
         };
         const magpie = new MagpieTransformer(options);
@@ -73,7 +77,7 @@ describe('Test magpie-transformer', () => {
             } else {
                 const time = timer.end();
                 timer.start();
-                time.should.be.greaterThan(2000);
+                time.should.be.greaterThan(200);
             }
             if(counter === 2) {
                 done();
@@ -159,6 +163,72 @@ describe('Test magpie-transformer', () => {
         magpie.end()
     }).timeout(5000);
 
+
+    it('Test delay with slow server', (done) => {
+        const options = {
+            objectMode: true,
+            logger: coreMock.getLogger(),
+            delay: 200,
+            concurrent: 1,
+            highWaterMark: 10000,
+        };
+        const magpie = new MagpieTransformer(options);
+
+        // listener to check output
+        let counter = 0;
+        let timer;
+        magpie.on('data', (data: any) => {
+            data.res.body.should.contains('ok');
+            if(counter === 0) {
+                timer = new Timer();
+            } else {
+                const time = timer.end();
+                timer.start();
+                time.should.be.greaterThan(1200).lessThan(1300);
+            }
+            if(counter === 2) {
+                done();
+            }
+            counter++;
+        });
+
+        // send three mocks and measure time between results
+        for(let i = 0; i < 3; i++) {
+            const mock = JSON.stringify({url: 'http://localhost:3000/timeout'});
+            magpie.write(mock);
+        }
+        magpie.end()
+    }).timeout(50000);
+
+
+    it('Test server partial not available', (done) => {
+        const options = {
+            objectMode: true,
+            logger: coreMock.getLogger(),
+            delay: 200,
+            concurrent: 1,
+            serverTimeout: 100
+        };
+        const magpie = new MagpieTransformer(options);
+
+        // listener to check output
+        let data = 0;
+        let timer;
+        magpie.on('data', (err: any) => {
+            data++;
+        });
+        magpie.on('error', (err: any) => {
+            if(err.code === 'ESOCKETTIMEDOUT') {
+                data.should.be.eq(1);
+                done()
+            }
+        });
+
+        // send three mocks and measure time between results
+        magpie.write(JSON.stringify({url: 'http://localhost:3000/'}));
+        magpie.write(JSON.stringify({url: 'http://localhost:3000/timeout'}));
+        magpie.end()
+    }).timeout(50000);
 });
 
 /**