150 Johnson Fast Strike wot rpm drop

[Gene Holder]

'91 on Ranger is in otherwise top shape. Will initially turn full wot rpm and then drop back about 600 rpm. Carbs have been cleaned, compression good on all six, ignition redone last season, but #1 plug looks wet or black while all others are nice and tan<br /><br />Eng used in bass tournament fishing so is either off or in a Helluva hurry.

 

[JB]

Re: 150 Johnson Fast Strike wot rpm drop

Howdy, Gene.<br /><br />You are losing a cylinder as soon as the ignition system gets hot.<br /><br />Verify this by pulling plug wires. The dead cylinder(s) will cause no drop in rpm.<br /><br />Switch Ignition parts until the trouble switches.<br /><br />If you have lost 2 cylinders, side by side, overhaul the carb for those two.<br /><br />Good luck.