A few ideas:
An obstruction in the exhaust or air intake
Faulty stop solenoid
Is the preheat working correctly
If you have bled the fuel system and have fuel in the lines to the cylinders – perhaps a clogged injector
Also, I know you probably know this but be careful if the engine cranks but does not start. Remember to drain the water-lift muffler after a few cranks as the exhaust will not push the saltwater up the exhaust and it will back up into the pistons.
With best regards,
Super Maramu 2000
Currently cruising: Marsh Harbour – Abaco Islands - Bahamas
From: amelyachtowners@... [mailto:amelyachtowners@...] On Behalf Of amelliahona
Sent: Tuesday, January 19, 2016 9:21 PM
Subject: [Amel Yacht Owners] Onan Cranks But Won't Start
My boat, SM #335, has an Onan 7MDKAL-431 Spec B, 7 kW genset. It has 2,300 hrs on it and it has been basically flawless with normal matinenance. 6 months ago I changed the oil, it operated fine and we put it on the hard in Puerto Rico for the hurricane season. Now, having splashed yesterday, I can't get the darn thing to start. It cranks, attempts to start but will not sustain combustion. Inspection of the water pump reveals all impeller blades intact (new impeller), no missing blades to account for since last change. The oil level is good, oil is clean. It seems to crank a bit slow, so I took the starter off, cleaned up the brushes and commutator and re-installed it cleaning up all the terminals as I went. Still cranks seemingly slow, but realy plenty fast to start if somehting else wasn;t wrong. I changed the fuel filter and bled the system. I checked all the sensors (mine doesn't have the fault flashing light sytem). I installed my new spare electric fuel pump (what a pain in the a..), the engineer that designed that location should be keel-hauled. I'm kind of running out of ideas. Browsed the forum back a year or two and didn't come up with this scenario or additional ideas. Any additional thoughts?
Appreciate the help.
Gary Silver, Amel SM #335 Puerto Del Rey - Puerto Rico
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