88 5.0 rpm problem

[lynnboy021]

i have a sunbird barltta 229 with a 5.0 well it had a 5.7 but could not fix the problem with the 5.7. anyways motor starts up really good and idles good also but in the water is a another story. i dont know if my motor is to small or what my rpm is at 3 to 4 rpm but the boat really only goes like 5 to 10 mph. i try playing with tabs and trim but no luck but if i am at wot with about 3 1/2 to 4 rpm i can feel a kick and when i get that kick the boat wants to take off so i have 2 props i think they are 15x15 and 15x17 i think but both are the same speed and rpm.... now on my 5.7 everything worked really really good so all i did was just changed motors but i dont know if this will make a diff but on my 57 the carb had a spacer about 1 inch and on the 50 i did not put that spacer do i need it?? maybe i have a carb problem??? oh i have a 2 bbl rockchester thanks

 

[lynnboy021]

Re: 88 5.0 rpm problem

anyone???

 

[91rr]

Re: 88 5.0 rpm problem

Have you tried running the other prop? It sounds like your prop might be slipping.

 

[lynnboy021]

Re: 88 5.0 rpm problem

yes i did but both are the same and both are brand new never used. how do i know what type i need for my boat?

 

[mcleaves]

Re: 88 5.0 rpm problem

Sounds like a spun prop hub or engine coupler. Dropping in engine size isn't going to help your situation, but your description of revving with no speed and then an occaisional catch sounds like slippage someplace in the drive system

 

[91rr]

Re: 88 5.0 rpm problem

I would have to agree with mcleaves. I bet it is the engine coupler or the splines on the shaft. When you put the prop on does it slip on the splines or is it nice and tight? You might also try putting it in gear and try turning the prop by hand to see if something is slipping. With the engine off of course.

 

[91rr]

Re: 88 5.0 rpm problem

Did you ever figure out your problem?