I know this is an old chesnut and has been well thrashed out in this
group, but I have group googled about this ongoing problem and none of
the answers quite fit. I had the outboard serviced recently by the
Johnson agent in my area, the thermostat was replaced and everything else
checked out, however the motor will only run at full throttle for 2 mins
before the overheat alarm comes on. I use a 50-1 2-stroke oil
fuel mix. Once throttled back to idle, alarm goes off in 2-4 mins. After that
I can plane at about 2/3 throttle indefinitely The water pump indicator
at the top of the motor has a steady stream out of the hose at all times
and after the OMC warning goes off, the water stream is hardly warm let
alone hot.
I have checked for debris clogging the intakes etc. Motor is flushed out
with fresh water after EVERY trip. Spark plugs are correct model and
new. I don't think the motor is overheating at all, but I play safe anyway.
Before I go back to the agent, can I get some suggestions as to what might be
the problem. Details of the rig:
1989 30hp Johnson electric start 2-stroke, runs only in salt water on a
4metre aluminum runabout. I use only Johnson oil products.
thanks
Brian M