runs rough

bullstedman

Cadet
Joined
Dec 26, 2010
Messages
18
I have a 18304 a evenrud 1973 she runs rough at lower rpms its like a intermittent engine miss. It has new plugs it doesnt seem to do it after half throttle. could this be a points issue or a coil or is it the champion plugs?
 

rickryder

Commander
Joined
Jun 24, 2010
Messages
2,722
Re: runs rough

Might be a carb issue.... How dose it idle? Have you cleaned out the carb?
 

bullstedman

Cadet
Joined
Dec 26, 2010
Messages
18
Re: runs rough

Its seems to idle fine but rough at times it will run perfect and flutter and than smooth again.
 

rickryder

Commander
Joined
Jun 24, 2010
Messages
2,722
Re: runs rough

It wouldn't hurt to drop the bowl on the carb and see if there is any dirt in it.....sometimes a bit of crud floating around getting stuck in a passage will give you idle/low rpm roughness... Check if you have a good spark and if you haven't looked at the points that wouldn't hurt either....check all wire connections for corrosion and that they are tight.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,385
Re: runs rough

Basic health check.
Compression
Spark
Fuel delivery
Spark plug condition
Post results.

If you don't know if the carb's are due for a service then they are due.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: runs rough

I don't find a 18304 only 302,303.1963.?
Also don't find any 73 18hp.63s have a low speed mixture adjust.
Sounds like a lean sneeze.With it warm in gear Adjust the lowspeed needle toward rich (out)
till it smooths out.
 
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