Roush Motors Prices??

[Got the Bug]

Originally Posted by GEE TEE

What was the fix for your stumble? My Roush 427R has a tip-in stumble that I have been working on. I tried to get info about the carb setup from Roush to verify that mine hasn't been tweeked by someone, but no reply.

Mine has the Holley Street Avenger 870, but I noticed that Roush is now supplying them with the 770 carb.

How long have you owned the motor? My recommendation would be to go back to the dealer that you bought the engine from and ask them to be your advocate in getting the issue resolved. This was a known problem on some motors several years ago and Roush ended up swapping out the carbs.

[Roush #1]

Gee Tee

Check on the top of the float bowl and see if you have a paint dot there.
My 427SR #444 came with a 770 with a blue dot on the top of the float bowl and had the stumble problem. Roush sent me another carburetor with a green dot on it and the problem is gone.

I don't really know the difference in the two and it is nothing visible. The green dot model has the same size air bleeds, squirters and jets as the blue dot.

I know two other Roush 427 owners that had the same stumble problem and Roush replaced their blue dot carbs with green dots and fixed the stumble.

Jody

[jhv48]

If that doesn't work, try richening up the idle air screws about 1/8th of a turn out each. That stumble could be a slight lean transition.

Worked for me on another engine.

[GEE TEE]

Originally Posted by Got the Bug

How long have you owned the motor? My recommendation would be to go back to the dealer that you bought the engine from and ask them to be your advocate in getting the issue resolved. This was a known problem on some motors several years ago and Roush ended up swapping out the carbs.

My engine is #180, built in 2005, it now has 13,500 miles. Since I'm the third owner of the car/engine I doubt Roush will help me out with the performance issues. In fact, I've contacted them twice asking for carb tuning specs (jets, power valves, diaphram springs) so I could verify my carb is as it came from Roush. So far, no response. There are lots of things I'd like to know about this engine (recommended plugs/gaps, timing, advance curve) but Roush is keeping quiet. I have eliminated my tip-in stumble through a coordinated attack on initial timing, advance curve, idle speed, idle mixture, and diaphram spring change. The jets and power valves should be OK based on the AFR plot on a recent dyno sheet I received with the car. The car is much more driveable now although it still won't idle below 1100RPM, and it bucks and complains if I ask it to cruise below 1800RPM. Maybe I'm just asking too much from an engine with a big (how big is Roush proprietary info) cam.

[madmaxx]

Mine cruises all day at 1400 rpm as smooth as a rolex watch. You need the correct carb, it is a knonw issue with early Roush engines. You need to find the right person at roush to talk too.

Originally Posted by GEE TEE

My engine is #180, built in 2005, it now has 13,500 miles. Since I'm the third owner of the car/engine I doubt Roush will help me out with the performance issues. In fact, I've contacted them twice asking for carb tuning specs (jets, power valves, diaphram springs) so I could verify my carb is as it came from Roush. So far, no response. There are lots of things I'd like to know about this engine (recommended plugs/gaps, timing, advance curve) but Roush is keeping quiet. I have eliminated my tip-in stumble through a coordinated attack on initial timing, advance curve, idle speed, idle mixture, and diaphram spring change. The jets and power valves should be OK based on the AFR plot on a recent dyno sheet I received with the car. The car is much more driveable now although it still won't idle below 1100RPM, and it bucks and complains if I ask it to cruise below 1800RPM. Maybe I'm just asking too much from an engine with a big (how big is Roush proprietary info) cam.

[SP01715]

Originally Posted by GEE TEE

My engine is #180, built in 2005, it now has 13,500 miles. Since I'm the third owner of the car/engine I doubt Roush will help me out with the performance issues. In fact, I've contacted them twice asking for carb tuning specs (jets, power valves, diaphram springs) so I could verify my carb is as it came from Roush. So far, no response. There are lots of things I'd like to know about this engine (recommended plugs/gaps, timing, advance curve) but Roush is keeping quiet. I have eliminated my tip-in stumble through a coordinated attack on initial timing, advance curve, idle speed, idle mixture, and diaphram spring change. The jets and power valves should be OK based on the AFR plot on a recent dyno sheet I received with the car. The car is much more driveable now although it still won't idle below 1100RPM, and it bucks and complains if I ask it to cruise below 1800RPM. Maybe I'm just asking too much from an engine with a big (how big is Roush proprietary info) cam.

Call Lance at Hillbank. He has the direct number to the department at Roush that builds these motors. He called the guy on a sunday on his cell when I had a question, and I had my answer in about 5 minutes.