diff --git a/stopify-continuations/src/runtime/runtime.ts b/stopify-continuations/src/runtime/runtime.ts
index fe02ecd3..0181ba50 100644
--- a/stopify-continuations/src/runtime/runtime.ts
+++ b/stopify-continuations/src/runtime/runtime.ts
@@ -11,17 +11,17 @@ import { FudgeRuntime } from './fudgeRuntime';
 export * from './abstractRuntime';
 
 let savedRTS: RuntimeImpl | undefined;
-export function newRTS(transform: string): RuntimeImpl {
+export function newRTS(transform: string, stackSize: number = Infinity, restoreFrames: number = Infinity): RuntimeImpl {
   if (!savedRTS || savedRTS.kind !== transform) {
     switch (transform) {
       // Default to shallow runtime.
       case 'catch':
-        savedRTS = new LazyRuntime(Infinity, Infinity);
+        savedRTS = new LazyRuntime(stackSize, restoreFrames);
         savedRTS.kind = 'catch'; // TODO(arjun): Sloppy
         break;
-      case 'lazy': savedRTS = new LazyRuntime(Infinity, Infinity); break;
-      case 'eager': savedRTS = new EagerRuntime(Infinity, Infinity); break;
-      case 'retval': savedRTS = new RetvalRuntime(Infinity, Infinity); break;
+      case 'lazy': savedRTS = new LazyRuntime(stackSize, restoreFrames); break;
+      case 'eager': savedRTS = new EagerRuntime(stackSize, restoreFrames); break;
+      case 'retval': savedRTS = new RetvalRuntime(stackSize, restoreFrames); break;
       case 'fudge': savedRTS = new FudgeRuntime(); break;
       default: throw new Error(`bad runtime: ${transform}`);
     }
diff --git a/stopify/src/runtime/abstractRunner.ts b/stopify/src/runtime/abstractRunner.ts
index 8c7a681e..0b78d7c1 100644
--- a/stopify/src/runtime/abstractRunner.ts
+++ b/stopify/src/runtime/abstractRunner.ts
@@ -59,6 +59,11 @@ export abstract class AbstractRunner implements AsyncRun {
    */
   init(rts: Runtime) {
     this.continuationsRTS = rts;
+    
+    this.continuationsRTS.stackSize = this.opts.stackSize;
+    this.continuationsRTS.restoreFrames = this.opts.restoreFrames;
+    this.continuationsRTS.remainingStack = this.opts.stackSize;
+
     const estimator = makeEstimator(this.opts);
     this.suspendRTS = new RuntimeWithSuspend(this.continuationsRTS, this.opts.yieldInterval, estimator, () => {
       switch (this.mayYieldFlag.kind) {
diff --git a/stopify/test/semantics.test.ts b/stopify/test/semantics.test.ts
index 8c5f0aee..cb63b8d7 100644
--- a/stopify/test/semantics.test.ts
+++ b/stopify/test/semantics.test.ts
@@ -290,7 +290,7 @@ describe('Test cases that require deep stacks',() => {
         yieldInterval: 25
     };
 
-    test.skip('non-tail recursive function (deep, lazy)', onDone => {
+    test('non-tail recursive function (deep, lazy)', onDone => {
         const runner = harness(`
             function sum(x) {
                 if (x <= 1) {
@@ -299,7 +299,7 @@ describe('Test cases that require deep stacks',() => {
                     return x + sum(x-1);
                 }
             }
-            assert.equal(sum(200), 1250025000);
+            assert.equal(sum(100000), 5000050000);
             `, { captureMethod: 'lazy' }, runtimeOpts);
         runner.run(result => {
             expect(result).toEqual({ type: 'normal' });
@@ -316,7 +316,7 @@ describe('Test cases that require deep stacks',() => {
                     return x + sum(x-1);
                 }
             }
-            assert.equal(sum(200), 1250025000);
+            assert.equal(sum(100000), 5000050000);
             `, { captureMethod: 'eager' }, runtimeOpts);
         runner.run(result => {
             expect(result).toEqual({ type: 'normal' });