trouble with an early 80's model 25hp

Joined
Oct 11, 2012
Messages
19
Ok let me start by saying this motor runs like a dream. The problem isnt the running with this one it the power. Itseems to not have any power when i get it on the water. I have it on a 14 foot v bottom aluminum fishing boat. it should have more than enough power to posh it. When i barrel test it it revs great and pushes the water strong. When i take it out fishing and ask it for the torque to push this little boat it barely gets the boat moving. the engine doesnt rev up like it would if i had a slipped hub, so that problem is solved i think with the hub. its like it is straining to push the boat. I had a 9.9hp merc on the same boat that pushed it 5 times better than this one does.. Can anyone help me out with this one? Where do i start? the foot is great no slipping Plugs Wires and Coils are all new and marine grade. Carbs have been cleaned and adjusted properly so im lost now..
 

jasper60103

Commander
Joined
Sep 18, 2008
Messages
2,055
Re: trouble with an early 80's model 25hp

I have an '81 25 hp Johnson and it pushed my 16' semi-V in the low 20s, and my setup weighs about 400#.
My first thought is you could be running on one cylinder. Have you done a proper spark test yet?



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Joined
Oct 11, 2012
Messages
19
Re: trouble with an early 80's model 25hp

yes i have replaced all coils wires and plugs.. checked the spark to make sure flywheel is doing its job from the magneto and the sparks great it doesnt skip like it would if it were only running on one cylinder
..
 
Joined
Oct 11, 2012
Messages
19
Re: trouble with an early 80's model 25hp

or stator which ever one you want to call it.. lol i get them confused..
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: trouble with an early 80's model 25hp

May I ask how you are testing your spark?
 
Joined
Oct 11, 2012
Messages
19
Re: trouble with an early 80's model 25hp

testing it by pulling the wire off and using a spark tester that plugs into the wire like a spark plug and it lights up greatly..
 
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