9.9 to 20 HP Suzuki that doesn't go to full speed well

[biederboat]

I got my Suzuki 9.9 (DF9.9BTHSS) that worked fine except didn't go fast enough for my 14' Klamath so I got the 20HP update and it seems to work fine except that at high speed it starts throttling down. I pressure up the oil hose and that doesn't make it work good so it must be something inside. Is it possibly the filter (which I did replace it) or something else? It seems to do it very regularly so I'm just thinking it's something inside that I need to update or fix up.

Thanks for any help!
Biederboat

 

[99yam40]

I got my Suzuki 9.9 (DF9.9BTHSS) that worked fine except didn't go fast enough for my 14' Klamath so I got the 20HP update and it seems to work fine except that at high speed it starts throttling down. I pressure up the oil hose and that doesn't make it work good so it must be something inside. Is it possibly the filter (which I did replace it) or something else? It seems to do it very regularly so I'm just thinking it's something inside that I need to update or fix up.

Thanks for any help!
Biederboat

I guess this oil hose you speak of is the fuel line to the motor, and you are pumping the bulb.
Is this 20 also a 4 stroke motor?
do you think the motor is overheating or low on oil or low oil pressure causing the RPM limiter to slow down the rpms?

 

[biederboat]

I guess this oil hose you speak of is the fuel line to the motor, and you are pumping the bulb.
Is this 20 also a 4 stroke motor?
do you think the motor is overheating or low on oil or low oil pressure causing the RPM limiter to slow down the rpms?

Oh sorry, I meant that gas (not oil) hose that I pressured up that didn't help it. And it is a 4-stroke. I did replace the oil recently (for a new one, quick change). I do think it is all something about the gas coming into the outboard but is it maybe before, in or after the fuel injection?