toolbox

I have a 97 35' Fountain that ran 88.5 on gps @5600 rpm's last year. Over the winter I put on Imco -2" lower units on and I am running 88 on gps now at 5600 rmp's. Everything is the same except the lower units. I was told I should except to see a 4-5 mpn increase and personally was excepting to see an honest 3 mph increase.

My question is has anyone else had this problem? If you did what steps did you take to improve your speed? Would adding a 1" spacer possibly give me more top end? Did I possibly raise the X dimension 2 high?

Also, I am told that the boat has a stock X dimension. How would I go about checking my X dimension?

Any info good or bad would be greatly appreaciated. I want to get past that 90 mph mark pretty bad.

Thanks in advance,
T.J.

mrv8outboard

what is the gear ratio? what is the prop pitch? and what were the rpm's @wot again? this way we can see if it is just alot more slip.

toolbox

1.5 gear ratio, labbed 28 p hydromotives, 5600rpm's @ wot,

Imco told me today to try 28 bravo's beacuse the hydromotve's have to much stern lift. Has anyone heard of this?

Strip Poker 388

I have heard that about the hydros.

Your x dim may be high to start with on the boat.

rv

Something is wrong, your rpm should have gone up if you are using the same prop. Are you at the rev limiter at 5600 rpm? Even if you had a high X before it is even higher now at your rpm should have gone up. Your slip may go up too and not get anymore speed. Then it is time to try different props to get your slip back down. But for now you need to figure out what is wrong.

Rick

toolbox

There are no rev limiters on the boat.

sterndrivespec

we put two inch shorties on a step bottom 35 and gained about 4 or 5 mph.but you MUST use bravo props.hydro's dont work on shorties.we are going to try merc's new 5 blades on that boat in the near future.

toolbox

Thank you for the input. I am testing some 28 Bravo's this weekend. What hind of power did you have in th 35? I would like to know some of your set ups if you would mind?

Thanks
T.J.

Jonas

i have got some 30's b-1's that are supposed to be cut down to a 28 but still have the gain of the 30's dont really understand that but thats what i was told.
if u want em i paid 1000- + frt on oso last yr i would let em go for 550+ frt
i clearing out all the sets of props i bought for the old boat.
also stellings standoff boxes 3500 - new never in water.. just kickin around garage

Treadwellmotorsports

toolbox.

first of all if your under 90 a nose cone will loose you speed. you may try other props to get your speed up a little but bottom line is your boat is to slow. at about 92 to 93 mph the nose cones or i should rephrase the torpedoe on the shotries will hurt you. if you did a standard shortie you would be ok. oh and if you go to bravo's the boat will not handle as well. bravo's are not surface prop's. hydro's are more surface props. keep what you have and add a little horsepower then you will see a big gain..

Treadwell