Performance issues with 1989 Pirata 454 engine.

[gogger]

We have been working all summer to get the engine running well in the Pirata. She runs great at higher speeds. But when we have been idling a while or running at slower speeds like when surfing. She seems to load up and not want to idle very well. Will stall when trying to accellerate. It has a holly carb. We put a new coil on and new spark plugs. It still has the points and condenser distributor. Just wondered where you think we should go next in the quest for better performance?

[92SupraComp]

check your timing and also sounds like the carb needs to be rebuilt. you can have a mechanic do it and it will be like new. or you could send it off to a aftermarket place and actually get much better performance from it. (ie. Jet Performance, A.E.D.)

[cadunkle]

Stall when accelerating sounds like accelerator pump. Look down carb and push throttle, should see two strong streams of fuel down the throat while moving the throttle. If you do see this, you may need a different accelerator pump cam or larger discharge nozzle. Before doing any carb tuning though, verify your initial timing is set correctly. 8*-12* should be good for initial, so long as it starts easy and doesn't detonate. I have my 454 running at 10* initial. While checking timing, verify the timing advance smoothly with RPM and returns to the initial you set it at. Timing not advancing and coming down properly could cause stumble/stall and poor idle.

If you haven't changed the points and condenser, do so. Take care to gap properly and verify gap after running briefly. Worn points means weak and inconsistent spark. You can lightly file off any carbon tracking or pitting with a fine file or fine sand paper, blow off points after. This will help if dirty but accelerates wear on points.