Prop Selection on a "New to Me" Rig

studlymandingo

Commander
Joined
Mar 22, 2006
Messages
2,716
I've been reading over several of the threads on this forum for prop selection. Very helpful and interesting stuff. I just traded in my old 16' CC with a 75 Evinrude for a 1986 18' Winner Sea Quest Center console. The boat is equipped with a 150 Mariner that appears to run quite well. The boat had a dinged up, chunked out 14 X 70 aluminum prop on it. I put it in the water with this prop just to give it a quick trial run. I was given a 14 3/4 X 23 SS Yahama Prop by the guy I got the boat from. I immediately put the prop on, and headed out into Tampa Bay. The first thing I noticed was the sky, it quickly came into view when I pushed the throttle forward. It took longer than I wanted to plane off, and the RPM's at WOT were around 4800. I realized this was too much prop for my setup, and went to a local marine salvage shop to see what kind of trading I could get into. I traded the prop for a SS Rapture 14.25 X 21, and headed back out into the bay. The boat planed out faster, not as fast as I would have liked, and I was getting 51-5200 RPM at WOT. I had the 60 gallon tank full, and my 220 lb neighbor on board. After returning home, I read about the vent holes for hole-shot performance, and the Rapture already had holes, but there were plugs in them; I've taken them out, but a cold front has pushed in, and the water was really rough today. It was difficult to restrain myself from going out anyway, but somehow I managed. I'm hoping for improved hole-shot, but obviously the 5100 WOT is too low. Do I need to have the prop pitched down slightly, will a different brand work better, could the engine be in need of a good tune-up? These are all questions that I just don't have answers to yet. I'm hoping that some of you out there can help.
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: Prop Selection on a "New to Me" Rig

Pull your sparkplugs and see if you're running on all 6. If any are burning differently than the others, there may be a problem. I'd expect the 21 to do better.
 

studlymandingo

Commander
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Mar 22, 2006
Messages
2,716
Re: Prop Selection on a "New to Me" Rig

The plugs all looked like I would expect to see in an outboard. I dumped a can of SeaFoam into the tank (approx 30 gals in a 60 gal tank). I took the vent plugs out of the prop. Ran the boat around Pinellas Point in Tampa Bay. I do get a better hole-shot, and the WOT is up to around 5400. The motor is running more smoothly, I really think there was some stale gas in the tank when I got the boat last week. After reading all of these posts regarding the motor height, I think I'm going to raise it a notch and give her a run to see any difference there may be. I'll keep the posts coming regarding my results.
 

Ron G

Commander
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Apr 28, 2005
Messages
2,905
Re: Prop Selection on a "New to Me" Rig

You really need to stick to one thread,did ya do what they suggested on the other thread yet?
 
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