Prop Change?

[lahiggs]

I have a 76 MGF with 75hp Evinrude. The boat runs good, but if I have 3 or more people in the boat I have to ask everyone to get in the bow so I can get up on plane. It has a 13x19 prop now, would it help if I went to a 13x17? If so, what sort of top end will I lose? Whats a good prop to get? Is aluminum the best? Any help would be greatly appreciated. Also, I read somewhere about cupped and uncupped? What exactly is that? How do I know if I have either?

 

[DJ]

Re: Prop Change?

First off, what is your wide open throttle RPM? It should be at least 5500. <br /><br />I would be willing to bet you are over propped. A 19" is a lot of prop for a 75 looper.<br /><br />Yes the 17" will help. You may not lose any RPM.<br /><br />I would go as far as saying you may need a 15".<br /><br />Cupped is the shape of the blades. Cupped props hold a bite on the water better and can be run trimmed up higher. Any cupped prp will be identified as so Most props for mid to larger size outboards are.

 

[lahiggs]

Re: Prop Change?

Anyone have any suggestions as to the brand of prop would be best for 15' tri-hull? I am new to the prop game and would love to get it right on the first try. What part does diameter play? I am unsure of my RPMs at WOT, I have no tach and dont know if I want to spend $200 to get one.

 

[sloopy]

Re: Prop Change?

Tiny Tach = $30.00

 

[lahiggs]

Re: Prop Change?

where do i find one of these tiny tachs?

 

[cobra 3.0]

Re: Prop Change?

http://www.cabelas.com/cabelas/en/t...nt=0&cmCat=srchdx&cm_ven=srchdx&cm_ite=srchdx

 

[lahiggs]

Re: Prop Change?

Does anyone know which would be better? Aluminum or stainless steel? I cant find any 13 diameters in stock, so I guess I will go with 13 1/4x17. Does this sound alright? I have the tiny tach on order now, thanks!

 

[lahiggs]

Re: Prop Change?

I have another question. How do I know if I have a largee gearcase or small gearcase? The engine model is 75643D.

 

[lahiggs]

Re: Prop Change?

I switched from a 13x19 to a 14x17. Unfortunately, while washing it today, I broke the sppedo, so I dont know if I was going faster or slower. The holeshot was better though.