Logo

Tohatsu 9.8 4T won't accelarate from idle

csobml

New member
Hi
I have the problém with accelerate from idle speed, motor getting shuts off. The engine is 5 years old carrefully maintained and has driven up to 100 mth. In past the motor working well, this year before first start I have adjusted valve clearance (exhaust valve of 2nd cylinder was slightly out of limit). Start and restart is quick without problém , idle going well, choke working, high rev is possible and stable, but quick trottling from idle is not possible, Engine is equipped accelerate pump, so the the first opinion pointed on problém with it. Carb seemed perfectly clean however was cleanned two times with pressure air, and fisching line- jets, tubes, check hoses, clips. Accelerate pump was cleaned and checked function from operational position with throttle rod. Throttle cables was checked for synchronize. From my point of view the movement of knob from accelerate pump is too small for neccessarry effect. When I press the knob manually during throttling, engine accelerate well, but throttle rod don't allow press the knob more. Some models does not have accelerate pump anymore and working, well, may be the problem is otherwhere. Please for help.
 
What is your actual model?

Did you do a complete disassembly of the carb (including jets and emulsion tube nozzle), followed by an overnight soak in real carb dip, followed by a thorough blow-out of all passages with generic carb spray? Just blowing out with compressed air is not adequate cleaning.

It does sound lean, so I would review all the cleaning, and make sure the accelerator pump works well when on the motor.

Also verify that the oil is not over full.
 
Thanks for reply
Model is MFS 9.8 A3S. The carb was not cleaned completly. The jets was unmounted cleanned and inspect deeply. Emulsion tube nozzle was cleaned only by air. I am not sure how to unmount them, in the repair manual is not described this operation. Some tubes contain valve which looks like as one direction through. Where to focused on more? Could you describe how to do it, is it possible to do in home condition? I do not have special tools.
 
After the jets are out, the nozzle pops out the bottom. No valve. There are many small passages that must be cleaned in addition to just the jets.
 
Back
Top