Honda 4 stroke outboard

[mikehoyt]

This question also posted on C&C Owners groups.

Looking for input from other Honda outboard owners who may have encountered same problem.

I have 7.5HP 4 stk circa 1979.

Works very well most of the time.

Occasionally it will stall. Usually about 5 - 10 minutes after first started and usually when departing a marina and shifting from reverse to fwd. (not very comforting). Only happens about 1 in 10 times.

Lower plug fouls a bit over time (one month of using every weekend). Upper plug does not foul. Using NKG plugs from Honda dealer.

Occasionally will skip while running.

A separate problem occurred initially this year but has since disappeared. Water pump was working but not pumping sufficient volume. Discharged water was scalding. After boat was docked it started to work fine and has worked well since.

What I am looking for here is others who have had similar symptoms and an idea of what fixes worked. Engine is on the way to the shop and I wish to have the dollars spent in the right places rather than on a tune up that does nothing.


Thanks,

mike

[fishclan]

Mikehoyt
I would start with a Compresion test if that comes up normal, Then it would most likely be in the ignition.
David

[Variant_530]

I did have a similar problem. Not all that you mention but I did have insufficient discharge water exiting the engine. The engine seemed to over heat and stall periodically.
I found that the thermostat was completely encrusted in salt and corrosion residue.
I removed the intake manifold cover and cleaned out the thermostat and water snorkel and it fixed the problem. Now the engine runs fine.

[Hobgoblin]

Mike,

I have a 9.9 hp Yamaha approx. 2 years old now, and i had a similar problem last season.
One plug was fouled( don''t remember which one) and when testing(this winter,at home) at had almost no water exiting the engine as well.
Thru last season it seemed that whenever i had to enter and dock at the busiest locks it stalled when needed but only when shifting from FWD to REV.
I cleaned all cooling tubes( whitout taking the engine apart)and flushed with water thru adapter at the bottom (near prop).
Adjusted valve timing,they were all to wide.
Renewed plugs and oil and had a testrun.
Now runs like a swiss watch, without stalling( 2 months now)I''m still wondering if it was the baby-clams(fresh water) fouling the tubing,or bad plugs or a combination, but I think I''ve tackled my problem.
Best regards,

Marc, The Netherlands

[mikehoyt]

Received back from shop yesterday.

Compression is fine.
Valves were adjusted but were not far off to begin with & not source of problem.
Carb was cleaned and all tiny jets, etc.. blown out.
etc...

Fouling of lower plug appears to be wearing of rings over time (20+ years). It has been suggested that I use a plug that burns a little bit hooter in lower cylinder.

Thnking I should be on lookout for new motor over next year or so...

Where is thermostat located? Would like to check that.

Thanks,

Mike