Engine Won't Idle After 45 Minutes

phatsat67 wrote: You just need to look at the indicators and determine if it's fuel related or ignition related.

Or both! Actually looking (like looking under the hood of your car) won't tell you everything you need to know. Without a fuel pressure gauge and multimeter you're just guessing.

I believe I know the solution with all of you having the same problem since I just went through this myself. Look down your carb after it's all warmed up and shut off (remove flame arrestor), and if it's dripping gas down the primary (front 2 holes)you've found your problem.
The solution may be one or several things.
1. Fuel pressure too high.
2. float valve not sealing
3. debris in float bowl blocking valve.
4. float level set too high
I was sure it was 2,3,or 4 since my fuel pump was stock, but after ruling out everything else including a new carb, it turned out my old stock fuel pump was putting out 10 psi. A autozone fuel pressure regulator (dial type) was just crap, leaked and pressure was inconsistent. A new Holley fuel pump was still too much pressure
not to drip and flood. Finally a new Holley fuel pressure regulator made it work perfect after a few adjustments. No more shower into the carb. You really can't tell anything without a fuel pressure gauge I found.
Of course, I also had a weak spark due to bad points to confuse me even more.
It's all sorted out now. Hope this helps someone.

BuffaloBFN wrote: What are yall getting in the flame arrestors?

After only 21 years it was completely plugged with black gunk.

I have the usual spacer under the carb, and since everything was new, thought a vac leak was out of the question. My idle got unpredictable, and i realized that the gasket was not wide enough on the spacer-to-intake side. It had sucked itself in to create a leak. I made my own gasket, and all's well.

Bosch232 wrote: Issues: Starts and runs fine after first starting. Ski for awhile (approx. 45 mins.) and eventually when at idle the motor will chug and then stop. It starts back up but you have to idle at much higher RPM to keep engine running. Once it is time to ski and you take it out of neutral you have to quickly put it in gear and start pushing the throttle up or it will stall.

I had this exact problem on my 1989 2001. Numerous remedies were tried by mechanics without success including a carb rebuild.

What DID complete solve this problem was cleaning out the completely plugged metal flame arrestor on top of the carb by soaking in gummout then blowing dry. Amazingly, none of the mechanics had thought or bothered to clean it.

Ross, what lake do you go out on?

I would definetely look for a vacuum leak...I had this also..cold it would idle fine..once it got to running Tº it would stall, or need to move the screws to get it running etc...I had a leak between carb base and manifold...due I had changed the stock one for a performer....

is there black stuff in the exhaust, this will indicate a rich mixture. A sticking float will dribble fuel at idle that will cause the issue you speak of....

        1989 Nuatique 2001
          Motor: Pleasure Craft Marine
          Type:   351
          Model: PLD-PR-R12
          Carb: Holley 4 barrel (dont know the model number)
          Motor hrs: less than 400

Issues: Starts and runs fine after first starting. Ski for awhile (approx. 45 mins.) and eventually when at idle the motor will chug and then stop. It starts back up but you have to idle at much higher RPM to keep engine running. Once it is time to ski and you take it out of neutral you have to quickly put it in gear and start pushing the throttle up or it will stall.

A carb rebuild is in the works, but the puzzling thing is that it's fine for the first 45 minutes or so. Suggestions & Ideas welcome.