I have an Evinrude jet drive outboard motor that runs great; but when put in the water, the rpms will not come up to increase the impellar when the throttle it put down. Once you take it out of the water and put it in gear; the rpms will go up and it runs great. Can you tell me if this is an impellar problem or something else? Motor was rebuilt last year but the impellar was not replaced.

SOURCE: free download for repair manual for an Evinrude

My outboard motor is old and used.When I went to run it for the first time everything worked except when I went to put it in forward gear the boat went slowly but when I gave it more gas the engine just reved up but the boat wasn't going any faster.The motor is 40hp gale model.I think because it is bought used the prop is not the right one and it seems like it's slipping as I go faster.
I would appreciate any feedback on this problem.

Thax, Don

SOURCE: gear box oil leak

Here is a website where a manual for you outboard may be purchased.  Outboard Marine went out of buisness in 2000 and thus no parts of origial manufacture are support is available . Therir are secondary markets .    THe Lower case splits in half and their is a seal around the prop shiftm which is pressed in. The seal between the cases are cut o-rings which are placed and glued into place with gasket seal.
The water pump is located where the case splits a little bit higher. You must open the little port on the side and take out one of the screws to the connecting shift linkage to split the case. After splitting the case the drive shaft and water pickup tube(s) wil come out of the powwer head or the tubs may stick into the power head which is ok. Place the lower skag into a vice and remove the 4 or 5 screws to the water pump housing. Remove and replace impellor and impellor plate if available. If part(pieces) of the rubber impellor is missing flush out the tubes and the power head to remove them.   When reinstalling the lower unit use a flash light to make sure that the tubes return  to the proper place in the power head and the shift lever is resecured. If you need more assistance, just write back. I was an Outboard motor mechanic for five years about the time of your motor.  

SOURCE: Johnson Outboard Motor 175HP

Not knowing what year it is...Light and alarm? Reason: overheat low oil etc. check water flow..water pump. The motor is most likily going into S.L.O.W mode. its a fail safe system. Last possibile reason ..CDI box and or stator.. pull plugs check compression...should be 120-150 lbs.

SOURCE: motor kills when put into gear

u have no spark in #2 cyl check for spark with plug if its week regap it

SOURCE: My mercury 35 hp outboard motor idle's fine but won't run

While at the river try to adjust the fuel air mixture. When you are on the water it puts the engine under a load and if that dont work then dont be afraid to bump up the idle stop screw slightly.