[Harry21Z]

First post, but long time reader. I am the proud owner of a 98 Talari Z216 Cuddy. Its is set up with the 5.7 efi Bravo one. I bought the boat 10 yrs ago and have enjoyed many hours on it with only a few issues. This forum is great and i love that the club has grown over the years!
Quick thanks to all for helping me get closer to some prop issues. I run my boat at 8600 feet above sea level in CO. So needless to say much of the prop talk does not help me since i run at such high altitude. But recently i went to Lake Powell and bought a new prop and the boat ran like it has never run before. Ran a 17p four blade aluminum solas. i had a full tank, 4 adults and a ton of crap and i got up and out quickly. The 4 blade made a huge differnece. Now im wondering about getting a 4 blade for my higher altitude boating and maybe a SS for next yrs Powel trip. ANy thoughts?

[WetWilly]

Hi Harry21Z and welcome to the club!

Can you tell us the difference in altitude is between where you normally boat and Lake Powell?

WetWilly

[Harry21Z]

Hey Willy,
I normally boat at 8500 feet above sea level in Colorado.
I believe (dont quote me) that Lake Powell, Bull frog, Utah marina, is about 3600-3700 feet above sea Level.
After Powell, I loved the performance of thealuminum 4 blade 17 p blade so much I couldnt wait to try it at my normal lake. Well, at 8500 it didnt do as well as my 3 blade SS 15p. So i guess i will soon try and demo a 15p 4 blade SS.

[WetWilly]

Hi Harry,

It sounds like you're running too rich at the higher altitude and it's possible your EFI can't deal with that much of an extreme. I would try and give Mercruiser a call to see if there is any reprogramming they can do for your EFI system to compensate for the thinner air at 8600' before I go prop switching. Now I'm not saying your Mariah wont benefit from a new prop, but if the motor isn't performing at it's peak, all you will be doing is trying to compensate for this condition with the prop, which isn't a good solution.

A quick way to see if you're running too rich is to check the plugs after running around a bit at your regular boating spot. If they come out black (sooty) you're too rich (the ceramic tip should be tanish in color if the fuel/air mix is correct).

WetWilly