Mercury 500

ericanderson

Recruit
Joined
May 6, 2012
Messages
2
i have a mercury 500 50hp from mid 70 (i think) it will run good out to my best fishing spot after a while i try to come back it idels rough and has no power (wont stay running) even with choke and high idel.
any thoughts.
i squeez the ball fells stiff but wont run. HELP ME
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Mercury 500

Start with the simple checks.

What is compression on each cyl?

Spark test, can you get a hot blue arc across a 7/16 inch gap on each plug wire?

With the engine trimmed level and the motor NOT running, shift into Forward gear and open the throttle to WOT, look down the carb throats while squeezing the primer bulb, watching for ANY fuel. A firm hand-shake is all that's needed, crushing the primer can overcome the floats and cause flooding. Are any of the carbs flooding?

Repost your finding and the serial # of your motor so we can be sure which ignition you have.
 
Joined
May 4, 2012
Messages
22
Re: Mercury 500

I have this same engine. I do not know much about outboards. If I flooded it, does that mean fuel will leak out of the carbs? Also, I tried to use the choke and all I got was a click. My ignition is the top mounted kind.
 

ericanderson

Recruit
Joined
May 6, 2012
Messages
2
Re: Mercury 500

Start with the simple checks.

What is compression on each cyl?

Spark test, can you get a hot blue arc across a 7/16 inch gap on each plug wire?

With the engine trimmed level and the motor NOT running, shift into Forward gear and open the throttle to WOT, look down the carb throats while squeezing the primer bulb, watching for ANY fuel. A firm hand-shake is all that's needed, crushing the primer can overcome the floats and cause flooding. Are any of the carbs flooding?

Repost your finding and the serial # of your motor so we can be sure which ignition you have.

the compression is 85-90 all cylinders the serial # 3820556 1974 they dont look like they are flooding
thanks for your reply
 
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