Still stumbles at take off

[mikebc]

Hey guys, thanks for all of your help so far, but I can't get rid of that darn stumble when I first put the hammer down. It's a '87 3.0. Last night I put the ignition kit in to replace the points, a little more power and a touch more speed. I reset the timming to 6degrees, it was way the heck out at 12! I've put in new plugs, wires, cap, rotor, and decarbed the engine. I also cleaned the heck out of the carberator with spray cleaner and ran 2 tanks of cleaner in the gas. My fuel is very fresh and midgrade. This stumble at take off is only for a second, and then it runs fine. Starts and idles fine. This stumble came with the boat when I purchased it last year, I just can't seem to shake it! Thanks again guys, Mike.

 

[rodbolt]

Re: Still stumbles at take off

that is most likly the biggest complaint on a 3.0.<br /> the ones with the mercarb tend to be worse. it may be time to open up the carb for a refesher. some stumblked when new. some I could play a bit with and get most of it out. others still had a hint of stumble even after everything. seems if you get it past 1000 or so its less.

 

[JStutz]

Re: Still stumbles at take off

I have had the same trouble with mine since I bought it last year. I have even rebuilt the carb with no luck. Gonna have to live with it!<br /><br />Jeff Stutz

 

[mikebc]

Re: Still stumbles at take off

It does have a mercarb on it. The stumble sounds like something I'll just live with then, maybe a louder stereo system will take care of that stumble, say 80-90 decebels worth! Thanks guys.

 

[trog100]

Re: Still stumbles at take off

we used to call that kinda thing a flat-spot.. its the switch from idle jet to intermediate.. there is a brief weak mixture spot as the throttle is opened .. its kinda built in with some engine/carbs and hard to get rid of..<br /><br />u could try running the idle mixture a little on the rich side.. even if it means adjusting the throttle stop screw to make up for it idling slightly slower cos the mixture is bit rich..<br /><br />if its possible to play with the accelerator pump linkage and get it to start squirting gas a little earlier that might help..<br /><br />my mercarbed engine dosnt do it.. thow looking at the plugs it does seem to be running on the rich side.. which is probably why..<br /><br />course.. going straight from engine idle to full power dont help things like this.. i always take mine up slowly.. he he..<br /><br />trog100<br /><br />ps.. u could also try those "projected nose" NGK plugs like i use.. BPR6FS.. is the number..