485 Merc starting hard, running rough and wont idle

[chris mig]

First I will say what I have. 485 merc with pertronics, electric fuel pump. I have good fuel pressure, the carb was rebuild last Sept. and was running awesome for the 2 trips we had at end of season. I had 2 runs 2 weeks ago and ran perfectly, 1 run out last week was good as well but the next trip 44 hours later I had found I had left the key on, it started and ran rough but then cleared up at higher speed, (and noticed my oil pressure was lower than usual 40 psi, usually around 70) and that went to normal when it cleared up. Before I get out there and tear in to all kinda stuff, could I have damaged the coil with the ignition on for all that time. I am a shellfish diver and need to get to work as quick as possible. Any help will be greatly appreciated, for where to start

 

[Scott Danforth]

its never the coil. coils either work or down.

what is your compression numbers?
what is your fuel pressure?
what is your starting procedure?
when was the last time you cleaned the carb?

 

[chris mig]

carb cleaned in Sept, 3psi fuel pressure, couple pumps off throttle and held at about 1/3 to 1/2 throttle. fresh rebuild low hours. was just running strong the other day

 

[chris mig]

Ok so I found bad wire connection at resistor wire now it runs as it should. But now tiring to dial it in an finding it wont run well at idle unless the air/fuel adjusting screws are in all the way. Should I just pull carb and go thru it again? It was done last Sept and when winterized I ran ethanol free fuel thru the system before fogging.

 

[chris mig]

So just found a sloppy rotor, swapped that out with another, way better. Also just found one spring on my air/fuel mixing screws to be larger than the other WTH (bought that way) swapped them both from another carb, thank god for spare parts. Running 100% better