Mercruiser 470 won't fire when warmed up

arnettmark

Cadet
Joined
Sep 5, 2010
Messages
11
I just purchased a 1979 SeaRay with a 470 Mercruiser. If I shut it down when it is warmed up, it never wants to restart. It turns over fine but won't fire. I'm planning to replace cap/rotor/plugs/wires & check the timing, as well as a carb rebuild this winter. Anything else I should look at?
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Mercruiser 470 won't fire when warmed up

carefully check the point advance plate.
had some issues were it lost the ground when warm.
some I even had to route a seperate ground wire for the plate.
 

EddiePetty

Lieutenant Junior Grade
Joined
Aug 25, 2008
Messages
1,008
Re: Mercruiser 470 won't fire when warmed up

"If I shut it down when it is warmed up, it never wants to restart. It turns over fine but won't fire."

....first, by all means, conduct a COMPLETE tune-up prior to any troubleshooting!!

Then,the next time this no-start condition shows itself, remove the flame arrester and slowly advance the throttle to all-ahead full so as not to squirt fuel from the accelerator pump. Peer into the carb's throat all the way to the bottom of the manifold. Inspect for LIQUID fuel either dripping from the venturis, bowl vent or fuel pump vent line. Any evidence of LIQUID fuel from these ares indicates the need for either, and/or repairs to the carb/fuel pump.
Additionally, after a re-start (with the flame arrester still removed), inspect the throat of the carb for the same aforementioned sources of LIQUID fuel.
:)
 
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