[mrichzx14]

Hi my names Matt and Iam new to this site, just recently bought a 93 barchette and it has a 4.3.
The motor needed some work so we tore it apart and in putting it back to gatter we decided to port the heads. I dont no if it helped out but I took it out with a 19 pitch and its runing 47mph on the gps at 5,800. Was thinking of putting a 23 pitch on it to get it down to 4,800, what do u guys think.

[mikeyt]

Originally Posted by mrichzx14

Hi my name is Matt and I am new to this site, just recently bought a 93 Barchetta and it has a 4.3.
The motor needed some work so we tore it apart and in putting it back togetherr we decided to port the heads. I dont no if it helped out but I took it out with a 19 pitch and its running 47mph on the gps at 5,800. Was thinking of putting a 23 pitch on it to get it down to 4,800, what do u guys think.

I think your tach is out of wack. There is no way you are running that 4.3 at 5800 rpms. Access the backside of your tachometer and see where the small dial that is marked 2-4-6-8 is set. Give the dial a spin or two or three then reset it to 6cyl. More likely you are running at about 4800-5000rpms at WOT with the 19". You could try a 4 blade 20" or a 3 or 5 blade 21" to get your top end up a bit but i would suggest you find a shop that will let you test run a prop or two. You should be hitting 50-51mph if everything is in good condition. Going to a 3 blade 21" will likely mean you will lose a slight bit of low end grunt which means if you do any skiing, wakeboarding or tubing it will struggle a little.

[edgar]

Hi i have a 1996 mariah shabah 180 and trying to find out whats the stock prop that came with this boat. I put a new 14x23 aluminum prop and my rpms are at 55 full throttle. It had a 14x23 when i got it but looked pertty bad so i changed it.

[edgar]

Hey mikeyt i belive we have the same boat, what pitch are you useing on youre boat? I was looking to get more top end for my boat. This is the thing when i got the boat it had a 14x23 aluminum prop but it looked pertty bad so i bought the same prop but new. With the old prop its at 46 47rpms wot and trimed right. With the new prop its at 54 57 or more wot rpms. The hub looks good so what esle can i check.Do i need a bigger pitch?

[mikeyt]

Originally Posted by edgar

Hey mikeyt i belive we have the same boat, what pitch are you useing on youre boat? I was looking to get more top end for my boat. This is the thing when i got the boat it had a 14x23 aluminum prop but it looked pertty bad so i bought the same prop but new. With the old prop its at 46 47rpms wot and trimed right. With the new prop its at 54 57 or more wot rpms. The hub looks good so what esle can i check.Do i need a bigger pitch?

What is a "bigger" ptich? Something is wrong with either your tach or your prop dimensions. The most popular prop for the 180 with a 4.3L was a 14.25 x 19" pitch. The 3.0L will handle a 19" but sometimes a 17" works better. A 23" pitch would have your WOT rpms down under 4000 and the recommended range for either engine is 4400-4800 rpms at WOT. There is a small dial on the back of your tach that allows the tach to be set for the # of cylinders the engine has. Give the dial a spin a few times then reset it to either the 4 cyl or 6 cyl setting depending on which engine you have. Sometimes a bit of corrosion builds up in there causing the tach to read incorrectly.

All that said there is 1 member here who says he runs a 23" pitch on his 18' Barchetta with the 4.3L and gets good performance. I dunno how he does it but....I'm taking him at his word.