what would cause the motor to loose power?

[gazza2007au]

i brought my cousins johnson 9.9hp with a 15hp carby it has been sitting for 2 years i was the last person to use the motor 2 years ago and it ran good now i got it running it ran fine on the trailer than we took it down to the local lake we took off the motor powered up fine than bogged down for a second than picked up and ran fine for about another 20 seconds than it started to bog down than pick back up than bog down than pick back up while keeping the throttle at WOT but the motor would never stall what could be wrong? i also throttled back and the same thing happen just at a slower speed
also im having problems with the cooling system the motor got warm enough to the touch and my pee hole wasnt peeing much water if any at all mostly drops i used a compressor with compressed air to clean the pee hole nozel and i also removed the gearbox and used the compressed air to clean out in the water tube to make sure it was free of anything obstructing the water flow would it be possible for someone to show me a few pictures of a impeller shagged/on its way out/perfect so i can match it up with mine to see where i stand without me needing to pull my gearbox off again if its not needed

cheers

 

[tashasdaddy]

Re: what would cause the motor to loose power?

i think you will find you answer here, http://forums.iboats.com/showthread.php?t=299680

dirty carbs, clogged pee hose, temp also could be thermostat.

diagrams here: http://shop2.evinrude.com/ext/index.aspx?s1=86d3d72aeba35dacbc349b439cb45104

 

[Silvertip]

Re: what would cause the motor to loose power?

Surging as you described is very likely due to a lack of fuel -- probably due to a fuel pump that is going bad. You don't look at an impeller to tell if it's bad because many of them that are bad look perfectly fine. Replace it rather than risk destroying the engine due to overheat.