71 40 hp evinrude

rude 71

Cadet
Joined
Apr 29, 2012
Messages
7
iam at a loss i bought a boat from a fella and it ran pretty good the first time out.the sec time i notice a big loss in power at wot, what i have done since, replaced fuel pump,replaced both coils and condencers, checked points look great and regaped, cleaned carb put freash fuel in , replaced fuel connecter. the first time we checked it, the bottom cylinder was intermittent, when we unplug the top cylinder while running it has no change, but when we unhook the bottom cylinder the motor dies. we have checked the cutout switch by unhooking while running no change. i am at a complete loss have no idea where to go from here. my boys really want to go on the boat. wondering if anyone hase any pointers. PLEASE! thank you so much for your time.:confused:
 

rude 71

Cadet
Joined
Apr 29, 2012
Messages
7
Re: 71 40 hp evinrude


thank you for the info, i for got to mention the motor fires right up and runs. just dont run on both cylinders,you can hear the top cylinder trying to fire every once in a while. when we take plugs out you can tell the bottom is fireing but the top is just wet and doesnt look like its been fireing. also brand new ngk plug. sorry i know it is complicated but iam just frusterated. thank you again
 

rude 71

Cadet
Joined
Apr 29, 2012
Messages
7
Re: 71 40 hp evinrude

i have checked spark i have nice white fire that jumps 7/16" when i take the plug out it is soaked with fuel. still at a loss
 

akdiesel

Cadet
Joined
May 16, 2011
Messages
19
Re: 71 40 hp evinrude

Trash those ngk plugs and get the proper champion plugs sounds stupid but makes a difference. These motors don't do well with "HIGHER" grade plugs for some reason.
 
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