5.0 Stalls when opening throttle after warm up
 

Have a 5.0L V8, Alpha I on a 1993 MX20.
Have had the boat out twice since buying it and had the same problem each time.
Starts fine, idles fine, rev the throttle and all is good. Pull away from the dock, ride around for 5 or so mins at low RPMs, all is good. Gradually throttle up to get on plane and power drops out almost immediately and stalls. If I catch it soon enough and quickly rev the throttle is sometimes stays running for a few secs. Try to restart it, doesn't start. Quickly rev the throttle while trying to start it usually does and runs for a few second before stalling. After about 15 mins of this trying and waiting game it will start. I slowly increase the RPMs to WOT and it runs fine the rest of the trip at low RPMs and WOT. Any thoughts? I'm inclined to think it is a fuel issue but really have no idea.

Re: 5.0 Stalls when opening throttle after warm up
 

Sounds like it might be a bad accelerator pump on your carb. With the engine off, if you look down the carb, do you see fuel squirting when you open up the throttle? Another possibility is your choke is not operating correctly and is remaining closed.

Re: 5.0 Stalls when opening throttle after warm up
 

I had the same issue on one of my other boats in the past. It was an electric choke issue. It only cost me about $100 at the marina to get it fixed. Ran like a top after that.

Re: 5.0 Stalls when opening throttle after warm up
 

Was raining last night but will check the accelerator pump this weekend. Doesn't make sense that it would be the choke since each time I've let it warm up to operating temp before leaving the dock - not counting it out though. I also pumped out the gas since I have no way of knowing how old it is, having just bought the boat. I will try a new fuel and a new fuel filter this weekend. The gas smelled a bit different than the fresh gas I had in a can.

Re: 5.0 Stalls when opening throttle after warm up
 

Choke appears to be functioning correctly and the accelerator pump appears to be fine according to the test mentioned above. Finished emptying the tank. Dumped the filter contents into a container and it was about 40/60 water to fuel. Put on a new filter and added 10 gals of fresh fuel. Hopefully that was the culprit. We'll find out this weekend.

5.0 Stalls when opening throttle after warm up
 

Wow. That's a lot of water!

Re: 5.0 Stalls when opening throttle after warm up
 

Just got back from the lake. Bad gas was apparently the issue.

Re: 5.0 Stalls when opening throttle after warm up
 

It amazing what fresh fuel can do. One gallon of 10% ethanol fuel can absorb a tablespoon of water from humid air. I'm don't recall how long it takes to do that but ethanol likes water.

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Re: 5.0 Stalls when opening throttle after warm up
 

I had the same problem. Boat starts fine, idles fine, after warm up it reaches 3000 rpm and starts the stalling process. Release throttle and continues to run, then does intermediate stalls and finally quit. It starts again after cooling down but the same process. Gas was left I the tank with fuel stabilizer from last year but it does seem like bad gas behavior.