485 Mercruiser won't start

rtoomey641

Petty Officer 3rd Class
Joined
Jul 8, 2016
Messages
93
Hi new to forum 485 Mercruiser engine backfires and will not start carb was flooding took apart and cleaned ran fine before flooding overheated before that
 

boltonranger

Petty Officer 1st Class
Joined
May 2, 2004
Messages
204
More concise details help.
Do you have spark?
Are you certain you have fuel?
Did you dribble any fresh fuel into carb to try to start with?
Have you pulled the distributor cap and checked the pickups for carbon or corrosion?
Was anything done to the motor after the overheat, like compression test ?
Details please.
-br
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,830
If you overheated it, better do a compression check, might have blown a head gasket. That is a 470 type engine, so very sensitive to overheating.
 

rtoomey641

Petty Officer 3rd Class
Joined
Jul 8, 2016
Messages
93
Hi sorry so long to respond weird shift at work compression cyl 1(140) cyl 2 (135) cyl 3 (135) cyl 4 (132) new fuel pump just installed I think fuel line might be clogged tries to start runs for a second then dies when I look in carb I see wet gas that is confusing me is it running out or flooding?
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,830
Compression looks OK. On that engine it is wise to change the impeller every other year to prevent an overheat.
 
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