'92 carb problem?

[CWilliams]

I bought a 92 Four Winns 19' boat last year as a first timer. Has a 5.0L (302) with 19 pitch prop. Boat drove great during test drive with 2 people on board. Later with 4 adults/2 kids and pulling a skier, boat would not plane up without putting everyone up front and had a hard time increasing rpms. Also sputtered and hesitated when jamed to WOT for the hole shot. Figured not so good for a 200hp engine. Later realized engine had been modified with Edelbrock Performer 289 intake and Carter 4 barrel carb (625 cfm). had carb rebuilt but same results. Spark plugs are black, so not burning right. Sounds fine in idle, but smell the fuel burn with slight black smoke. Runs at 50 mph in WOT, which i understand is fast for this boat, but it surges a little at top speed. It seems the modification has shifted the torque to the high rpm spectrum and it has no torque out of the hole. Is the carb too big for the engine? What other problems might it be? I doubt it was recammed. thanks for any suggestions.

 

[petryshyn]

Re: '92 carb problem?

625 cfm sounds a little high for stock 289. I think it came with 550. Doubt that it can't be compensated for with adjustments. <br />Hesitation can be caused by a multitude of things. <br />>Be sure you have a good strong accelerator pump stream. <br />>Advance timing a little at a time until a ping is heard, then back off slightly. The max advance you can get will reduce hesitation. <br />>Carboned up intake valve can also cause hesitation. Use injector cleaner in every tank. This will help clear it out. <br />>If the carb has a spring loaded secondary valve, make sure the spring is adjusted to spec. (weak adjustment = hesitation)<br />>The hesitation can also be something as simple as an ignition wire, cap, rotor or plug breaking down(leaking to ground) under accleleration. Make sure the ignition system is up to snuff.........<br />>about the black smoke and plugs.....try lowering the float level and tweaking the idle mixture.(also be sure the choke comes off fully)make sure the float isn't saturated (heavy)<br /><br />don't "read" spark plugs unless the engine has been up to operating temperature the time before you pulled them. (An engine started for a minute or two will result in rich mixture (choke) and blackened plugs will be normal)<br /> This has been my auto experience.....hope it helps.