40hsp Yamaha outboard precision blend

[Scooter14]

Hello,
The engine starts fine and runs, I go 4-5 mph and when I go to full throttle I still only go 4-5 mph, I get no power to speed up?
Thanks

 

[99yam40]

Re: 40hsp Yamaha outboard precision blend

Give a little history on your motor .
When did it last run good?
What all have you done to the motor before and after problem showed up

 

[Scooter14]

Re: 40hsp Yamaha outboard precision blend

Hi,
The motor ran fine last year when the inflatable tube popped. Bought an new tube, started up fine this year, put in new gas, launched it and it ran fine. A few days later it ran fine for about 10 minutes and then started to bog down and I could not get it to go over 4-5 mph. I hauled it and cleaned the carbs, the tach goes up fine but I knew it wasn't under a load, launched it again (getting good at backing up) and still no power???
Thanks

 

[99yam40]

Re: 40hsp Yamaha outboard precision blend

Check compression and spark on all cylinders, then check timing just to make sure it is advancing like it is suppose to. If all that is good then it's back to the fuel/carbs.

Did the motor go under water when the tube popped?

 

[robert graham]

Re: 40hsp Yamaha outboard precision blend

Description of problem not crystal clear, but if motor revs up but boat won't go, then maybe a spun prop?