'95 speedster propulsion help

[Alinvictor]

Hi,
I have a 95 speedster and I am verry confused with what is going on. The boat seems to run ok 1/2 of the time. On the lake I am doing around 45mph@7000RPM. This is during the good running half. Sometimes while on the water after a brake when I am trying to move the boat I will have some propulsion up to 4000RPM and is doing around 10mph but as the more tuch I put on the trottle the engine speed jumps to 7000RPM and there is no increase in propulsion at all. It stays at the same 10mph. I have to mention this is happening for both engines at the same time(they both jump from 4000RPM to 7000RPM at the same time) and this event start ocuring sometime at the end of last season. The engines itselfs are running almost perfect and they both start in a millisecond with no hesitations. I am fairly good with the mechanical aspect of an engine but I have totaly no clue where this can come from. I am verry confused I am greatfull for any ideeas you guys can have.

Thanks
Al

 

[Bills86e]

Propulsion is thrust that when the prop turns, its like a screw to move the water in a contained space. When the hydrodynamic size of space increases, the thrust is
decreased. Your wear ring tolerance that surrounds your prop should be .008 as good, and .040 as bad. You may have Seaweed in your water inlet tunnels preventing flow. Hope this Helps!

 

[Alinvictor]

Thanks,
I have been reading alot and I think you are very right...:agree:

 

[voodoo]

Read the replies in the other post you have going for the same symptoms - me thinks you have a torn rubber tube or neglected grease and the bearing/seals are worn away.