9.8 tohatsu doesnt rev or go faster after half throttle?

[eeh1025]

Hi there i have a 2005 9.8 tohatsu four stroke short shaft and i have it on a 14 foot semi v boat, the cav plate sits about 2 inchs below bottom of boat.

heres the problem when i take the boat out there is 2 to 3 guys and gear and the when i start moving it seems like once i hit about 1/2 to 3/4 throttle it doesnt rev or go faster, could a proper change help me out i have the stock 8.5x9 should i swithc to 8.5x8 or 8.9x7 or should i try something else
thanks alot
Ernie

 

[tommays]

Re: 9.8 tohatsu doesnt rev or go faster after half throttle?

If it runs well ( reaches correct rpm and speed) when the boat has one person then you will have to try a smaller porp that allows the motor to reach the correct RPM with a full load

 

[TOHATSU GURU]

Re: 9.8 tohatsu doesnt rev or go faster after half throttle?

Raise the engine up on the transom bit by bit and watch your performance improve. When the engine is no longer improving in performance drop it back to the previous setting.

 

[eeh1025]

Re: 9.8 tohatsu doesnt rev or go faster after half throttle?

Hey there
thanks alot im gonna try and bring it up a bit also would u prop it down 1 size to the 8 or to the 7 factory is 9
thanks

 

[TOHATSU GURU]

Re: 9.8 tohatsu doesnt rev or go faster after half throttle?

Dropping down in pitch will increase RPM , but wait until you get the engine mounted correctly before you start making prop changes.

 

[docksider]

Re: 9.8 tohatsu doesnt rev or go faster after half throttle?

Raise the engine up on the transom bit by bit and watch your performance improve. When the engine is no longer improving in performance drop it back to the previous setting.

If I were to try this (just to see), should I worry about the growing gap between the top of the transom and the mounting bracket? Are just the clamps enough to secure things long term?

Thanks.

 

[TOHATSU GURU]

Re: 9.8 tohatsu doesnt rev or go faster after half throttle?

Wooden shims are the answer.

 

[docksider]

Re: 9.8 tohatsu doesnt rev or go faster after half throttle?

Wooden shims are the answer.

Easily done. Thanks for the clarification.