i just put a teleflex tach on my boat and it seems to read too high of rpm. i have it on a 1986 johnson 28hp spl. when the motor is at idle it is reading about 1300-1500 rpm and it is easy to hear the motor is not running that fast. at wot it reads almost 6500rpm. it doesn't sound bad at wot and considering it is pushing a 15 ft fiberglass tri hull with a 9 1/4 x 12 prop i don't think it could get to that high of rpm. i have the pole setting at 5. i double checked teleflex's chart and 5 should be the correct setting. does anybody know if johnson used differant pole setting for the 28spl? or even on the 25 or 30 hp? the tach zero's out when the key is turned on so i assume the zero setting is right. i'm using the johnson 3 wire plug wiring harness plugged into the control box for my feed so i also am assuming that it is wired correctly. black-ground purple-ignition grey-send i know i could just assume it is reading 6-800 rpm high and just subtract from the reading but that seems to defeat the purpose of a good tach. anybody have any suggestions of what to try?