1977 Evinrude 6 HP dies when Hot

[Bill Riordan]

!977 6 HP, when cold it idles perfect, take it out for a rip on the inflatable dinghy and it runs great! Then when I come back it won't run at less than 1/2 throttle, breaks up and dies.

So Far:

Carb rebuilt and cleaned about 1/2 dozen times
New fuel pump
2 new coils, one was cracked and I thought hat was the issue, nope....
new plugs
new water pump, telltale is strong
new thermostat
tank and hoses are new, I ran it with the gas cap cracked open thinking the vent was faulty/clogged.
Compression is 70 and from what I read that is normal for this motor

I do not see a temp sensor on this motor

Running out of ideas, btw this is the first year for electronic ignition, no points/condenser

Help!

 

[Bosunsmate]

how do your spark plug electrodes look?
Try a spark test when it is dying, sometimes thats the only way to know whether its a failing electric component.
But you could ohmns test the stator and everything but it seems like it will be ok unless hot

 

[boobie]

Do a cylinder drop test on it when it acts up. Find out if it's one cyl or both.

 

[tomhath]

Last fall the ignition module on my '81 Johnson 9.9 went out. Heading back to the dock it ran fine for a couple of miles, then died at idle when I got there. After that it would start and run for a second and die. Replaced the module and it runs fine now.

I can't say that's the problem with yours, but when it works cold and fails hot it's often the sign of an electronic component failing (capacitors/condensers are prone to it).

 

[racerone]

Run with a timing light.-----Observe spark behavior when motor falters.-----Test both cylinders.----What happens when you operate the manual fuel pump ?

 

[Bill Riordan]

Replaced the magneto coil this weekend, it tested fine when cold but that didn't tell me much, unfortunately it didn't solve the problem but at least I eliminated a possibility for $20....

About the only thing left to replace in the electronics is the CDI (Power Pack) , just about to order one.

The only other electronic part I haven't replaced is the timing sensor, my understanding is they either work or don't, not prone to impacts of heat, thoughts?

Bill