please help . please help 1997 force 120 hp

[robertrojo]

Question i have a 97 o 98 sportcraft 180 cc with force 120 hp and all am doing is 36 max mph at 5200 rpm with a solas 13 x19 pitch i want like 45 mph top end ... what can i do before i change the engine...

 

[roscoe]

Re: please help . please help 1997 force 120 hp

Well, you are running in the rpm sweet spot, so changing props would likely do little, if anything.

Is the motor mounted at the correct height?
Is there any difference in speed or performance at different trim positions?
Is the floatation foam in the hull waterlogged? Are you trying to haul around an extra 900# of water?

 

[robertrojo]

Re: please help . please help 1997 force 120 hp

Well, you are running in the rpm sweet spot, so changing props would likely do little, if anything.

Is the motor mounted at the correct height?
Is there any difference in speed or performance at different trim positions?
Is the floatation foam in the hull waterlogged? Are you trying to haul around an extra 900# of water?

I didnt even have fuel gas tank and only me and my two kids and wife let say 400 pound and my scuba gear and thats about it motor is from factory mounted so am pretty sure is good and no when intrimmed all the way up to the limit that the prop was rarely touching the water i gain only 100 rpm so from 35 mph to 36 thats it .... boat is in pretty good shape like new so i do know about the water u talking about ... thanks for helping me ....

 

[roscoe]

Re: please help . please help 1997 force 120 hp

What is the boat rated for horsepower?

I see boats like yours with 115 hp motors, so that "should" be enough hp.
But maybe not. Maybe your boat is just too heavy for that motor.

 

[robertrojo]

Re: please help . please help 1997 force 120 hp

What is the boat rated for horsepower?

I see boats like yours with 115 hp motors, so that "should" be enough hp.
But maybe not. Maybe your boat is just too heavy for that motor.

I read somewhere on this forum is rated for 200 but i also saw another year but with no diving platform and open in the back . It was runing 45 mph with a 80 yamaha ... thats why i dont get it ..... maybe my year is more heavy one question how can i check waterlogged ??? On the boat

 

[roscoe]

Re: please help . please help 1997 force 120 hp

OK, according to the NADA site, you should have a 1998 model, rated for 125 hp, and it weighs 1850 pounds.

1998 Sportcraft Boats Price, 1998 Sportcraft Boats Value & Used 1998 Sportcraft Boats Specs | NADAguides | NADA Marine Appraisal Guides

Add 450# to that for the outboard, battery, and 15 gallons of fuel and you have 2300 pounds, plus the trailer, around 500#.

So your rig should weigh approximately 2900 pounds. Thats kind of heavy.

The easiest way to check the foam is through an access hole, reach into it and under the deck, and check the foam for water.

Or you could take it to a truck stop, feed mill, moving company, etc, and weigh it.
Park it on the scale, unhook from your tow vehicle, and get a weight.

If it weighs around 2900#, great.
If it weighs 3600#, not so good.

 

[jerryjerry05]

Re: please help . please help 1997 force 120 hp

He's not pushing the trailer
The 5200 is a bit low.Should be about 5500.Dropping to a 17 will raise the RPM to 5500.
Not sure the speed will go up but your gas economy will get better.
You sure the speedo is right??
The stuff they put in these boats isin't the best quality.
A hose could be pinched off?
My speedo compared to my GPS is off about 3-4mph.
45 with an 80????? On a boat like yours?Sounds like a fishy story??
The type of bottom will have a lot to do with 45/80? A whaler type boat really screams with lower HP motors.
My dad had a whaler with a 70 and it did 40 and used very little gas.
You leave the plug in while it's out of the water?
Getting to the foam can be tricky? My boat,I'd have to cut a hole to get to the foam.
I cut up a boat just like the one I have. It had an extra 600+ pounds from saturated foam.
The owner left the plug in all the time.

One more thing!!! It's only a 125.Go faster= more horses!!

 

[robertrojo]

Re: please help . please help 1997 force 120 hp

The speed was taken from my phone gps.. i think is about the motor i agree with u more speed more horses ... thanks u all for the help and yes i dont really thrust the rpm gauge but it was steedy when i get 5200 rpm so it should be good