Re: [Amel Yacht Owners] Onan Cranks But Won't Start

Olivier Beaute

Good morning Gary,

the Onan sometimes starts with difficulties because of electric power (although the main engine starts easily).
Is your starter battery in good condition (how old is it?)? Did you charge it while your 6 months on the hard.
To make sure this is not a battery problem, start your engine first, run it at 1200 rpm, then try to start the genset.
The problem could also be the pre-heating plugs that are dead (is the starter battery voltage going down when you're pre-heating?).

In french, we say: let's start with the beginning! The beginning is the starter battery. Then you will investigate the fuel supply line...

Good luck.


On Wednesday, January 20, 2016 7:25 AM, "Germain Jean-Pierre jgermain@... [amelyachtowners]" wrote:

Hi Gary,

Think simple… if your engine starts then shuts down,  it is likely a fuel problem.

Good luck,

Jean-Pierre Germain,
SY Eleuthera, Amel Super Maramu 007

On 20 Jan 2016, at 04:57, 'Mike Ondra' mdondra@... [amelyachtowners] <amelyachtowners@...> wrote:


Hello Gary.
Aletes’s Onan suffered similar symptoms this last spring after not being used for over 6 months. Check my posting Aug 1, 2015 “Onan generator will not run”. Carbon buildup at exhaust manifold/mixing elbow junction had restricted exhaust flow to the diameter of a pencil. Once relieve she started on the first bump.
Mike Ondra
Aletes SM#240
From: amelyachtowners@... [mailto:amelyachtowners@...] On Behalf Of amelliahona
Sent: Tuesday, January 19, 2016 9:21 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Onan Cranks But Won't Start
Hi All:
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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