9.9 hp outboard evinrude is bogging down?

Question

My 12 ft aluminum boat has a 9.9hp motor bored out to a 15hp. Every time we've been out on the boat lately it seems to run fine until we try to get it goin full throttle it bogs down to where it is hardly moving.

We thought it was the fuel filter. But now im thinkin we have too much weight in the boat. Maybe it's not enough power to push 2 full grown men weighing around 200 each. But i really have no clue if thats it.

Answer 1

if weight were the problem it would bog worse when not full throtle. Im inclined to say you need to do a check of the spark plug for running to rich. i'd guess your not able to burn the fuel when full open correctly. also air filter is in question. see look at this as any engine. they require air, fuel, and spark. the faster it revs the more air, fuel and spark needed. the spark doesn't need to be hotter , just faster and solid, the air clearly needs to be there in larger volumes, and fuel needs to match the air supply.  I wouldnt expect the 15 hp to throw you out the back of the boat but should get you there.

Answer 2

check the bowl on the carburetor if it has any dirt in it clean it out,its sounds like its got dirt caught up in the main running jet,that will cause it to run like that,those are good little engines and it will push that boat with the weight you have in it,good luck.