Fast yesss but may be not enough.

[dompie99]

Good day to all and welcome to this new '' summer period ', again.

As stated a few times last year, I've rebuilt this 3.0L V6 225hp and started it this year and ran excellent.

My problem is ( or is it ?? ) this one.

Jacked up quite high with about 8'' of setback, I ran a Chopper 30'' at around 5600 to 5700 and the speed was around 80 to 82 mph on the GPS Speedo onboard.

Now the Foot was '' all the way down '' and couldn't ask for more, or so i felt.

When I got someone else onboard, the speed dropped by about 10 mph ...


What's wrong with this set-up.

HST Hydrostream.

[David - WI]

The motor you have is pretty heavy compared to a 2.4L or 2.5L... maybe other people have different results but I think to carry the weight of the 3L you would need more than 225 horsepower?

I don't think the "chopper" style prop is helping at all; you need something with "stern lift" instead of "bow lift" to carry the extra weight; I'm going through the same thing looking for a prop to replace the chopper.

The motor on my HST is about 100 pounds lighter and makes maybe 210 hp and ran 88 mph according to the previous owner.

[rankink]

How much does the 225 weight(is it an opti) ? what lower is on the engine? How high did you have the engine up in relation to the pad?

HST's hate the extra weight. Especially when running below 250 HP

[David]

Sounds like my life when I had a 150 XR4. Mounted on a Virage, add a passenger in the front, - 10 mph +/-. Same motor on an SS2000, same result. Now I did try putting the passenger in the rear with the SS2000, and my speed went back close to solo.

Option 1. More setback to offset the passenger weight
Option 2. Prop with more lift. The 30 choppers (except the newest) have less blade area and likely less lift.
Option 3. Get a 300.

[Dave_r]

I had a 700 lb Kevlar Stoker with a 2.5 260 ss, my dad had a HST with the same motor. The bottoms are almost identical.

i always lost 10 mph with a second passenger upfront. Those big deep tunnels are excellent for rough waterNAND turning but do not carry weight well. Drove it for 13 years tried every prop that exists it's just the nature of the beast.

My STV was also affected be a second passaenger but would carry through and just wind up over a longer run and get top high end but I still lost 7-9 mph on it with the same 260 I had on the stoker.
To make the HST less affected by a second passenger its about setback and weight, but your limited by the design of the tunnels as they are straight and do not progressively compress the air like a STV or newer designs providing more lift with less power.

- make sure the foam is dry and no unnecessary weight is in the front half of the boat (wet seats, crap under the deck,etc..)
- SETBACK, HST love setback but it costs in agility. I like hard turns and 18" or more setback can have the rear end slip around if your cutting hard , but if your mainly straight line running it's the way to go.

a member here BALZY I think had a HST with lots of setback that ran well someone may know how much.

finalky IMO a 225 pushing a relativity heavy boat to 80+ is doing well.

I had a healthy 2.4 225 carb bridge port on the Stoker and saw 92 on Radar, I think with play and a light load(<1/4 fuel) a stock HST should hit 85 ish but they are so impacted by weight.

my 30 cents.

[JohnR]

Is it an OMC or a Merc 3.0 225? There's a few quick, easy upgrades to get another 40hp out if the Merc assuming it's a regular EFI and not an Opti but like others have said prop selection and set back will effect it as well.

[BeefKid]

more setback... my buddy got one with a 225 omc on it and it ran 98 with a 28 has a stainless marine bracket on it and adding 3" plate... boat will run 100+ right now think he has bout 18-20" of setback runs great

[wired247]

Fat chicks slow you down!

[dompie99]

Lolllll. Fat chicks��. I live this one,, fornthe answers. Here they are:
It is an Black Max 225 originaly. .030 oversize with 300 heads and re-jetted according to the new size.
i have a LWP with dual water hoses and 1,62 ratio
i used a cleaver but at 30" pitch i will retry it This WE
Last year, i went 89 mph with a 28" but was kind of worried about rpm because it ran around 6000
i know Crankbearing has done the machining but i am still conservative with a 15 hrs engine on the rebuilt
it is a carbed engine. At about 250 hp's

[dompie99]

Okay, here a finding that could ''&%?%*?% ' change my perception about setback plates on an HST..

If you wait till the 29th second, you will se MY rig on the river rat that happened in 1992 or 1994 . and it ran 102 mph on radar.

https://www.youtube.com/watch?v=b9quZGWesw4https://www.youtube.com/watch?v=b9quZGWesw4

[dompie99]

Anyone have a sugestion ???

[dompie99]

Here are some numbers about last Week-end testings.

Prop: Cleaver 31''
Engine: 3.0L 225hp's
Gear ratio: 1,75 to 1
Engine RPM: 5200
GPS's Speed: 80 mph
Height: 1'' below Pad
Setback: 6''


Does these numbers sounds right, I get about 10-16% slip

[BeefKid]

at 5200 thats bout 8% slip... id raise the motor

[dompie99]

what would be your ''ball parc figure'' as of height ??

At this moment, I am at 1.5'' above pad.

[BeefKid]

id start lower than that maybe 3/4 up then if you still have water pressure and the boat feels good go up 1/8 or a 1/4 at a time just make sure you keep an eye on water pressure... if you loose it come down a 1/4

idk were my buddies motor is right now but like i said he has 24" of setback lol the prop is almost 5' from the pad... runs great too