67 80hp johnson engine misses and wont start after warms up

[pmack2787]

The motor will start right up when it is cold, but it will only sputter for a second without actually starting when it is warmed up. It also misses throughtout the rpm range. it has a freshly rebuilt feul pump, new coil, new plug wires, and plugs. I have checked all of the linkage adjustment. and the distributor timing. I have not rebuilt the carb but i did check the float level. I am running out of things to check. please help.

 

[OBJ]

Re: 67 80hp johnson engine misses and wont start after warms up

Take a look at the points pmack. Missing is generally caused by losing spark. You may just need a new set.

 

[pmack2787]

Re: 67 80hp johnson engine misses and wont start after warms up

I have filed the points with a points file, will this be good enough or will they have to be replaced

 

[Texasmark]

Re: 67 80hp johnson engine misses and wont start after warms up

I would change points and condenser. Filing works, but unless you have a very fine file and are good at getting the angles to match you may not have enough point surface area to conduct the current you need to charge the coil to enough energy to properly fire the plugs.<br /><br />A bad condenser could shunt current around the points (more than it's supposed to do) and keep them from interrupting current rapidly enough to get the required high voltage field for the plugs.<br /><br />Both could add to misfiring due to low voltage to the plugs.<br /><br />HTH,<br /><br />Mark

 

[pmack2787]

Re: 67 80hp johnson engine misses and wont start after warms up

thanks for the help does anyone know if there is a way to convert these to HEI ignition. points that are prone to corrosion dont seem to me like the most reliable option

 

[Texasmark]

Re: 67 80hp johnson engine misses and wont start after warms up

Ask a dealer and I agree on converting.<br /><br />Mark