Expert: chris Wethered - 5/12/2008

Question
I have a 4.5 hp  1985 mercury,cleaned the carb, replaced the points, but will still not idle. I had a guy look at at it he think it is something in the electrical. When starting to get in the trolling speed the motor will just stop, plug looks like good spark. I do not want to spend 120 to take it to a shop plus parts.  Need to know the best way to check coil,condenser any other.

THANK YOU VERY MUCH FOR LOOKING AT MY REQUEST

Answer

Hi Rick,

Coil Checking

remove the spark plug caps and measure the resistance between the high tension wires. 8k ohms +- 20%
Test resistance between the little pole and laminations. Reading should be 0.56 ohms +- 10%

Also you should rebuild the carbs, that should help with the idling.

Hope it helps

Chris