Wow I just looked at the prop on my boat and it is a 25 pitch that can't be good!!!It is hard to read the other numbers but I will try

A 25p prop would explain your slow speed....A stock 350 can't pull that prop...But something isn't right here. I would start with your tach. You can't be pulling 4800rpm's with the drive in and a 25p prop on a 350...The best way to trim your boat is to have the drive in/down to take off. Keep it there till your speed stops increasing. (Here is where your GPS will help) Tap your trim button for about a second or two...Watch your speed. You want to give it 5-10 seconds at each setting to make sure the boat gets setteled in. Then tap the trim again and watch your speed. Once your speed starts to slow down trim the drive back the same way till you get your max speed....THIS WILL BE DIFFERENT each time out based on water conditions,weight and balance of boat...I pull a full 500rpm's less with the drive all the way in...

BH

maybe its more like 4600 not sure this is the prop info quicksilver 48 3706 A40 25P what does all that stuff mean how can I find out the diamter of it

Missed a number in the sequence. Correct P/N is 48-13706A40-25P.

Got this direct from www.mercurypartsexpress.com.

"Mirage Plus Propeller
The part: 48-13706A40 has been substituted with: 48- 13706A46.
14 1/2 X 25 RH SS 3 BL"


BTW a 25" pitch is way, way too steep for that engine.
I'll be it was turning 4400 rpm and not 4800.
Engine rpm drops about 200 for every 2" increase in pitch.

4600 Still seems real high...I would guess more like 3800...Especially with the drive in..Double check that tach reading

BH

hmm
 

So I defenitly have the wrong prop on the boat?? Do you guys think that a 21 pitch prop 14 3/4 in diameter would get me to the rpm and speed I should be at? I also found my drive problem the peice that the hydrolic lines go into is cracked all the fluid came out should be an easy fix. I just want to make sure you guys think this will solve my problem before I go out and spend hundreds on a prop!!

I do.
Running a prop that big in pitch is over loading the engine. You stand a chance of burning it out if you continue. Besides, fuel consumption will decrease by going to a 21".

Which piece was cracked? The one under the outdrive?
Is the fluid, or what's left, look like a dirty milk shake? If so, the hydraulic system will have to be flushed out. Boy, you're in for a real treat with that chore. Here's a link to a similar topic where I posted flushing instructions. Flushing Hydraulic System

Its the piece under the outdrive that the zinc screws on to. As far as that milky stuff goes its not really milky becuase there is nothing left I will have to save that till next year I will try to make it till the end of the year. My rings both off of the selenoids oh boy

Huh????
You lost me on that one.

Re: hmm
 

I decent prop shop will let you pay for it and try it. If it's not the right pitch they should let you get another one. Just don't beat it up on your trial.