Boat ran great all day and then between a stop and going again it was hard to start backfiring and sputtering.  Won't idle below 1500 or 1600.  Idle screw has no affect as it won't stay at 1000 RPMs.  What could the problem be?


Got it to kinda run but it would idle at 2000 or so for a few minutes and then drop drop and stall out.  Runs good above 2k.

ANy ideas before I start messing with the carb and idle settings...I found a post on here with instructions for it.

It's a Holly 750 DP on a Ford 460.

You mean the gasket could be shot and there is a vacuum leak?

Will try tomorrow. Don't think the neighbors would enjoy the motor starting up right about now.

It only takes a few minute to pull the carb off and the gaskets are pretty cheap...replace anyways. cheap insurance!

Check your ignition timing as well. Might have a little effect on this, but the 460 likes between 10 and 13 degrees in my experience. (can be kinda hard to do this, as most marine engines have dampners from different years, etc.)

Best , and easiest, way to find true TDC on a 460, rotate the engine backwards (Tighteneing the crank bolt) until #1 is coming up on compression stroke, when at TDC, mark the dampner with a silver sharpie. rotate over again but watch #6 and when it starts to go down, mark it again. that should be 10 degrees BTC.

Also a good way to find out if your dampner/timing indicator are even remotely close.

That sucks! Glad you got it figured out though!