Speed problem?????
 

I cant seem to break 82mph I have a 34' advantage with twin 620's and bravo drives.I have tried going from a 4 blade prop to a five blade, lower and raise the drives even diffrent rotations on the drives,I have even taken everything out of the boat for less weight.Everything I try shows the exact same speed on gps speedo.Does anyone have any suggestions other then engine mod.

Re: Speed problem?????
 

Is it staying at 82mph with different changes. Or is 82 the best you have been able to get. I think we need more info.

Re: Speed problem?????
 

It is staying at 81-82 no matter what change I do.

Re: Speed problem?????
 

RPMs the same too?

Re: Speed problem?????
 

No,now with the five blade I droped from 5600 to 5200 rpm but a 25 pitch is to small always hit red line.So the five blade is getting me more speed for the rpm but I know that 400 rpm left is where all the power is.

Re: Speed problem?????
 

How old is the boat? Check for excessive hook at the transom.

Re: Speed problem?????
 

i agree -- check for a hook in bottom

Re: Speed problem?????
 

Have you compared notes with anybody with the same hull or the manufacturer?

Re: Speed problem?????
 

The hull is a 2002 and yes I talked to a guy with the same year as mine and he is running 84 with 575's and four blade props. That is a good idea about the hook I have not checked for that. Thanks for the advice I will get back to all of you and let you know what I found.

Re: Speed problem?????
 

Yep, if you have "hook" you will hit a wall reguardless of how much power you put in. --- JP

Re: Speed problem?????
 

May sound stupid but try bringing a hand held GPS with you next time you test, you may have a GPS Gauge that sticks!! Had same problem on Fountain.
Does the boat ride bow down?? Do you think it is plowing??
Of course a hook will slow you down but you should see difference.

Re: Speed problem?????
 

No,now with the five blade I droped from 5600 to 5200 rpm but a 25 pitch is to small always hit red line.So the five blade is getting me more speed for the rpm but I know that 400 rpm left is where all the power is.

What is the pitch of the 5 blades?
What is the pitch of the 4 blades?
speed@rpm with 5 blade?
speed@rpm with 4 blade?
What is a 620?
Do you have dyno sheets for the 620's?
What is peak torque rpm?
What is peak HP rpm?