No Planer

[ddrieck]

Have Merc 500, 50 horse, S/N 496513A on a 1979 16" Starcraft. I have pulled the carbs, taken them apart, and cleaned them. Reassembaled with the same settings on the needle screws. Did a de carb in the driveway hooked to a hose and earmuffs (smoked out the nosey nieghber) Installed new clean portable 6 gallon tank, fuel line, sweeze bulb, and spark plugs. Starts fine, idles smoothe but will not build enough RPMs to break over to plane out. I get a very very slight stumble at full throttle. Back it of just a bit and stumble goes away but still will not plane out. Could this be a lack of fuel volume and pressure? Should I rebuild the fuel pumps?

 

[Tadd_P]

Re: No Planer

just cause your idle screws were good before doesnt mean that is where they will be right after your cleaning man. Take the idle screws out 1 1/2 turns and then take them in till the motor stumbles. Then back them back out 1/8 turn or so. Then try to plane out you might be surprised.

 

[ddrieck]

Re: No Planer

I did back out to 2 full turns and started back in at 1/4 turn intervals. Still will not plane out. Even tried change to the extra prop that came with the boat. Still no Plane. Did pull the plugs during all this and they were wet. Maybe running so lean its rich?

 

[Tadd_P]

Re: No Planer

yeah something going on there. Your plugs should not be wet. Getting plenty of spark? Do you have a tester? If not get one. Are the plugs new? Something is causeing the wet plugs. Check into that before you mess with the carbs anymore. One wrong move there could end up in a whole in the piston.

 

[studlymandingo]

Re: No Planer

Verify that you have spark on all cylinders.​

 

[Laddies]

Re: No Planer

If your high speed jets are clean and if the spark advance is working. It almost has to be the high speed winding in the stator, Ck it

 

[RICKRICK1]

Re: No Planer

1978 SKEETER with Merc 500 (50) Had this same problem, would accelerate to about 2800 RPM and then would stumble. Found Bottom carb needle valve was sticking. Had to replace it. no further problems ran fine, planes fine. Hope this helps.