71 60hp erractic idle/hard start at times

[robertshadow]

Idles ragged, sputters & speeds up intermittently. Compression 150lbs on all 3 cylinders per cheap compression gauage. Carbs just<br />cleaned & kits installed (improved idle concern,but didnt fix it). On the #1 cylinder I can disconnect the plug while running or close the idle needle & the sputter will go away. If I <br />disconnect plug on 2 or 3 or turn idle needle too far in out it will die. If it sits for week or <br />several days its hard to start like no fire. <br />My gut tells me its an ignition problem, as I could find no issues with carb. Also seems to drop<br />a cylinder intermittenly while cruising, again seems like loss of spark for a split second. Coil<br />housing is cracked, but I cant find any external<br />carbon tracking. Also I cant imagine that only <br />affect number one cylinder. I am considering removing flywheel & looking at distributer cap/spark distribution setup (havent had it apart<br />before). I am looking for tips on diagnostic steps<br />I might take before dig into it or what others have found to be root cause on similar problems.

 

[OBJ]

Re: 71 60hp erractic idle/hard start at times

Pay attention to the points. There set at .010....as I recall. Make sure there clean and not burnt or have any oil around them. Take a Q-tip and clean them with alcohol if oil is present. If there really burnt, replace them.<br /><br />Look at the distributor rotor contacts. They tend to get crusty (from continued arcing) after a while and may need cleaned up. Same with the rotor contact itself.<br /><br />Make sure the distributor isn't cracked anywhere.<br /><br />These older distributor can be a real pain so be prepared to be patient.<br /><br />One thing to always remember with this system, always use a top notch battery. Make sure it's fully charged. A low battery can blow the amp. The battery must be at 12volts. A little below 11volts and you risk the amp.

 

[robertshadow]

Re: 71 60hp erractic idle/hard start at times

Thanks, it will probably be saturday before I get a chance to work on it again. Battery good & hot.<br />I have meter & can check voltage during cranking. <br />1 odd thing i notice when its hard to start, if the engine stops in the right spot, & the key is<br />left on, the engine will fire when I disconnect &<br />reconnect the lead to the points(i assume to points, it goes under flywheel). It will just almost bust off & run when this happens. 1st time<br />caught me by surprise. Good thing I didnt have my<br />hand on flywheel. I can back to turning it over by<br />key, & it wont even kick. I have seen some auto<br />ignition modules that wouldnt fire in crank position, but engine would bust off as soon as<br />ignition switch allowed to go from start to run. <br />Sometimes it seems to kick a little when I left of<br />the switch, but its inconsistent. Does seem to have slight oily residue around distrubuter area. <br />I guess I just need to remove flywheel & inspect.