1979 100 hp evinrude no top end power

Jayflash7

Cadet
Joined
Jul 7, 2016
Messages
15
So this is my first post on this site so bare with me. I have a 1979 100 hp evinrude i bought 2 weeks ago and took the boat out and it ran perfect. It planed out and got up to about 26+ mph on a 1979 19 ft manatee. No problems. The next day i took it out and flew all over the bay. I was then heading back to the boat ramp at wot and out of no where it lost speed came off of plane and stayed at that speed. I brought the throttle down and tried to get back up but it would just speed up to where it was right before plane. I would say about 15 mph tops. I tried pumping the primer bulb at wot and no change. Put it on the trailer and brought it home. The next day i proceded to purchase new spark plugs and check if all were firing and they were. I then took her out again and proceded to open her up wot and she took about 15 seconds to come up on plane but still not at 26mph . Then after a little bit she bogged down and came back to 15 mph and stayed there. The boat has been sitting for 2 years atleast. Shes starts like a champ and idles fine and at lower throttle you would think shes a brand new motor but once i try to open her up she tops out at 15mph and doesnt plane. Any info would be helpful. Thanks.
 

Jayflash7

Cadet
Joined
Jul 7, 2016
Messages
15
Im thinking the high speed jets are clogged in the carb. Was thinking of taking her out and pushing in the choke while im wot see if she takes off if that would even narrow it down to that symptom. Would it be worth a try? . Im just trying to figure out why all of a sudden she has no top end power.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
If you keep running it with suspected plugged carburetors you could do major damage !---No fuel = no oil.---Do a compression test too.---Clean those carburetors.----Remove the high speed jets found screwed into the bottom of the float bowls.--Four of them.
 
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