4 Blade Comprop
 

I have a 96 200 4.3 with a 4 barrel carb 220 hp, engine was replaced in 2007. Currently the boat has a 19 pitch 3 blade aluminum prop and tops out at 40 mph gps verified at 4800 rpm at 6200 feet elevation. It is very slow out of the hole, and I intend to get the smart tabs, but I have heard very good things about the 4 blade comprops. I was wondering what you guys thought about going to a 4 blade 18 pitch comprop? I don't mind loosing a few mph if it rips out of the hole.

Re: 4 Blade Comprop
 

Some people swear by composite props, some people swear at them. Personally, i think composite props are good for spares or smaller outboards. When it comes to performance they are the bottom feeders but they are less expensive. I guess you get what you pay for. An 18" 4 blade will increase your WOT rpms to over 5000 so you might consider a 19" 4 blade which will have less of an effect on rpms. See if your local prop shop can give/rent you a loaner to try out though.

Re: 4 Blade Comprop
 

When you speak of WOT are you referring to the max rpm at full speed or the RPM when you give it full throttle from a stand still. People keep referring to over revving. My Barchetta 182 with 4.3 revs at about 4200 rpm when I give it full throttle while tubing etc. My max RPM at full speed (on plane) is pushing 5000 so I usually back it off a bit. Looking for a better hole shot as well and others have suggested going from my aluminum 3 blade 14 with 19" to a four blade of same pitch and size. I guess my question is do I need a higher RMP at takeoff to get a better hole shot.
Shawn

Re: 4 Blade Comprop
 

Rpm's at WOT refer to the rpms when you are at maximum speed. The idea behind prop selection is to keep your WOT rpms within the manufacturers recommended range, which for the 4.3 (and many other motors) is 4400-4800 rpms. Running at over 5000 rpms simply induces extra wear on the motor / outdrive. Running at less than the 4400 rpms at WOT is causing excessive loading/lugging for your engine. Personally, mine hits about 4900-4950 at WOT which i dont believe causes a problem to worry about particularly since i very seldom run at much more than 4000-4500. If you are much over 5000 or less than 4400 at WOT then you are simply not running as efficiently as possible. Ideally, you should be somewhere around the 4700-4900 mark at WOT.

Coolfish: going to a 19" 4 blade will 'likely' add about 100-150rpms so if you are at 4800-4900 then i think you will be okay to make that change but you will be pushing the limit. Going to a 4 blade will definitely add some 'bite'. Adding a pair of Smart Tabs will also make a difference in your holeshot.

Re: 4 Blade Comprop
 

Thanks Mikeyt, I have already added smart tabs and they are great but still need some extra umph to get out of the hole with passengers in the back. Hate asking people to move to the front to get going. Will try a 4 blade prop next.
Thanks
Shawn

Re: 4 Blade Comprop
 

I ended up buying a 4 blade 18 pitch comprop for my 96 200 Shabah 4.3 mercruiser from bass pro shops, and even at 6000 ft elevation the boat rips out of the hole now. It smokes the 19 pitch 3 blade aluminum. I did loose about 3 mph on top, but well worth every penny. I would highly recommend one, plus they are cheap. I'm very happy with my Mariah now..... Every time I put the hammer down out of the hole I get a big old grin. People riding in the boat are amazed it only has a 4.3, they all swore it was a big V8.