I have a 1986 245 with the 230 engine. With over 500,000 kms (300,000 miles)

Most of the time it runs well.
However, several months back, it started to require longer cranking to start (in any weather). That was the only noticeable problem back then.

Lately, it sometimes starts but idles very rough. Sometimes when we are driving, and the motor is warm (or not) it will starts to "stutter" as if it wants to stall, then in about 2-3 seconds, it runs fine again.

I am wondering if this is indicative of an O2 sensor gone bad??

And I also read an archive that jobber O2 sensor for Ford (bosch) systems are the same unit for less $$$.

Thanks in advance for your input.

Goldy - in Alberta Canada (no snow yet.... :) )