prop question?

[wellcraft1]

I have a 1990 wellcraft 186 eclipse with a 175hp 4.3l mercruiser. The tach doesn't work. What pitch prop should I be using on this boat? (19p or 21p) Does anyone have a similar boat? My boat is 19.5 ft long overall and weighs 2700lbs dry weight. Currently, the boat runs 43 mph on the speedo w/ a 19p aluminum prop. I want to get a stainless prop though.

 

[achris]

Re: prop question?

The ONLY way to get the right prop is with a tacho.

 

[BMDODGE]

Re: prop question?

all you have to do is hook up a good timing light w/tach reading - find out what the RPMS are at with it at wide open throttle - i believe it should be around 4500 - 4800. if i'm wrong someone will correct me a 19p sound's good as long as your not over-revving it. what are you looking for in a prop ; speed or watersports (holeshot) ??<br />Bruce

 

[Chris1956]

Re: prop question?

Wellcraft1 - It would seem that you are at/near optimum, based upon my experience. I have a boat and engine combination very similar to yours (19' SeaRay BR w/ 205HP 4.3LX Alpha, 2500 pounds dry). I run a 21P Rapture SS, and have about the same top speed at 4500 RPM. <br /><br />I am always concerned abot running these iron pushrod motors ar high RPM, so I propped mine not to exceed 4500RPM, and actually never cruise higher than 4200RPM.

 

[Northern Eclipse]

Re: prop question?

I have Wellcraft 196 Eclipse with a 350mag and alpha1 drive I turn a 21p mirage at 4500rpm and about 58-62mph depending on load, try a 21p with a normal boat load and see if it will plane easy or not, If stepping up is not a strain then you should be fine, But if its lugging to plane then stick with your 19p, If tach is out, check at the ignition coil and see if the Gray wire has broken off, thats your tach's signal wire, You can get a new tach for about 25 bucks.