2002 johnson 90hp running problem

I have a 90 horse 2002 johnson it will idle fine it will run good @ about 8 miles per hr.Then the more throttle u give the worse it will run .mechanic has changed power pack,cleaned carbs,checked lines ,checked valves& still hasnt found the problem does anyone have any suggestions ??
Thanks

Re: 2002 johnson 90hp running problem

timing or fuel

try running, just before it breaks up try priming it, if it goes faster u got fuel restriction/lean condition

Re: 2002 johnson 90hp running problem

Sounds like you need a new mechanic, one that diagnoses before doing. Way less expensive that way!

Maybe a little more clear explanation rather "the worse it will run" might get more help. Is it breaking up and shaking, or running smooth, but no power?

Re: 2002 johnson 90hp running problem

wayneg said:

I have a 90 horse 2002 johnson it will idle fine it will run good @ about 8 miles per hr.Then the more throttle u give the worse it will run .mechanic has changed power pack,cleaned carbs,checked lines ,checked valves& still hasnt found the problem does anyone have any suggestions ??
Thanks

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Re: 2002 johnson 90hp running problem

I agrre with need a new mechanic beleive me i wasnt real happy with him,the boat is running like it isnt getting fuel skiping & sputering really bad when i first take off it seams to run good then i stop & take off again it acts up

Re: 2002 johnson 90hp running problem

Did your mechanic check the fuel line all the way to the tank pickup? You may have debris on the pickup screen, a cracked pickup tube, a sticking anti-syphon valve in the tank outlet, etc. Sounds like a fuel starvation problem, especially since it gets worse at higher power settings. Also, any air leak into the fuel line will cause starvation. IO would suggest looking at a shop manual for an organized check list of things to look for. Good luck!

Several things you might try to confirm fuel starvation: 1) try activating the choke/primer at high power to see if the running issue momentarily clears or, 2) spray fuel/oil mix into the carb throats while at high power. CAUTION: Do not operate the motor any longer than absolutely necessary will the inlet air silencer removed!

I really hate wrenches that just start throwing new parts at a motor, hoping one of them may fix the complaint.