Sun Odyssey 36i started life as a charter boat
with Sun Sail. The next owner hardly used it so for the last four years the engine Yanmar 3YM30
has probably run for a maximum of 50 hours.
This week I tried starting it after 2 months of non use.
fired instantly, roared for a few seconds then died. Further attempts to start failed.
I checked that fuel
filter/water separator is clean and by opening the bleed screw at the next filter established that fuel
is arriving at the next filter. There was a little air that I bled.
Still did not start.
I cracked open the nut at the aft injector. No fuel when cranking the engine with throttle open. I cracked open the nut where the injector pipe leaves the injection pump
and cranked. Still no fuel.
I loosened the nuts on the banjo fittings on the hose feeding the injector pump
from the filter and pumped fuel using the lever on the pump
. Fuel flowed.
I opened the filter on the engine. The cartridge has black muck and so has the bowl. The metal bottom of the cartridge is brown which appears to be rust presumably caused by water
in the fuel.
I cut open the cartridge, the inside is clean.
Then I removed the hose with the banjo fittings. The fuel is meant to flow through the bolt and then through orifices just before the bolt end.
The lower bolt smaller orifices were clogged with black algae. The upper bolt with larger orifices were also dirty but not clogged. The inlet to the injector pump
Here are my thoughts. I would appreciate any comments.
My positive test of fuel arriving at the injector pump by loosening the bolts did not establish fuel getting to the injector pump. The fuel bypassed the blocked lower orifices.
There is no fuel arriving at the injector pump or the dirt has clogged the pump and maybe the injectors. The reason for engine not starting.
The initial engine start and roar was due to a build up of oil
or fuel in the cylinders.
My question is:
How did the algae get past the two filters?
My thoughts are that the fuel has dissolved water
that went through both the separator-filter and filter on the engine.
The water separator-filter is probably not effective to separate water at the flow rate of probably less than 10 liters per hour (based on 2 liters use and 70% return to tank) of a small engine.
Through engine non use, the water separated out of the fuel in the hose and created an environment
for the algae to grow.
Can anyone think of any other reason?
I cleaned the filter bowl and banjo fittings. I am about to re-assemble with a new filter. Hopefully the engine will start.
Should I run injector cleaner though the pump and injectors?
Any advice or comments welcome.