?? spark plugs not firing ??

alandchris

Petty Officer 2nd Class
Joined
Dec 25, 2007
Messages
106
Hello Gents
Service Manual on order - probably another week to get it. Any help/advice would be appreciated.

2004 9.9 Merc 4 stroke elect start. Problem => starts perfect, idles perfect - throttle up and the motor does not respond, meaning it bogs. The bog is consistent from a little throttle to a lot of throttle.

What was done in the last week or two - total carb rebuild with Merc OEM parts. Carb cleaner and compressed air done - all passageways/jets are clean. Actually, all new jets put in. New plags, gapped at .035 as the owners manual indicates. Removed and blew out the gas line/bulb assembly. Replaced the fuel filter with Merc OEM. Fresh premium octane fuel in tank. Took apart the fuel pump - diaphram and all look ok. Tested fuel going into the carb by having the engine idle - pulled off the fuel line to the carb - appears the fuel is coming through at a healthy rate - although not a steady rate - more of a slightly pulsating rate. I did take the plugs off to inspect them, they appeared wet and "carbony" - and this was after a few hours of trying to get the engine to run correctly.

My local dealer recommended to rebuild the carb again - or buy a new one. I'm pretty sure I did the rebuild correctly as well as cleaning out all the ports.

Any ideas ?
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: ?? spark plugs not firing ??

There's a very good chance the dealer is right.
 

alandchris

Petty Officer 2nd Class
Joined
Dec 25, 2007
Messages
106
Re: ?? spark plugs not firing ??

Thx for the reply Laddies.

Without running a pressure test - does the fuel delivery sound normal to you, pulsating and all ?
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: ?? spark plugs not firing ??

Normally when a engine surges(pulses) it's fuel. You also should check the plugin and lines, it's quite common for a clean carb to be replugged from junk if the fuel line.
 
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