Need more power.

[bigpimpin]

Hello Everyone,

This is the 1st time I have ever posted on forums an I'm hoping to get some expert advice

I have a 2013 Xcursion X20C pontoon boat with a 25hp 4 stroke efi Mercury. The lake we stay at only allows 25hp max, I need more. Is it possible to increase to 35 or 40hp without cheating an buying a new motor an changing stickers. "not my thing" I run open around 5000 rmp's. but I feel like im setting still in the water. My buddy has a 25hp 2 stroke from 1987, its a 24 foot Harris and he blows by me everytime. Embarrassing really haha.... Any advice? Thanks

 

[Scott Danforth]

Re: Need more power.

Welcome aboard.

before you modify your motor, have you optimized your height of the motor, along with the prop?

A 2 stroke will spin up to a higher RPM than a 4-stroke

 

[bigpimpin]

Re: Need more power.

Sorry Im not sure what you mean? The motor does have tilt an trim if that's what your talking about? Also when I picked the boat up last year the dealer claimed that Mercury forgot to send the prop, They put a used one on an swore it was the right one.... It was not. the boat ran at 3000 rpm's. When they sent the new one an I put it on, It jumped to 5000. Are you thinking the dealer placed the motor too low on the boat?

 

[BatDaddy1887]

Re: Need more power.

...keep your tubes clean on the bottom and maybe install some underskinning (aluminum sheets under the deck to keep water from splashing back and causing slow down). Also, you may be able to find a prop shop near you who would be willing to "loan" you a few props to help dial-in the correct pitch for your setup.

 

[gm280]

Re: Need more power.

You could always get some DE lithium crystals...oh wait...that's solely used for warp speed...

My neighbor has a similar setup. He has a pontoon boat with a 25HP Mercury on it. We GPS'ed his top max speed at 11MPH wide open... So it is what it is... As its been said before...I'm given it all she's got captain...

 

[ElGringo]

Re: Need more power.

I don't know if this is the answer but, while reading on the boat design forum I learned that Longer can equal faster. Also check that you don't have too much weight forward keeping the front of the tubes submurged. Shift stuff back a bit and there are just a whole lot of triming tricks for the motor. Also does his have a shroud in front of the motor and yours not?

 

[bigpimpin]

Re: Need more power.

I don't know if this is the answer but, while reading on the boat design forum I learned that Longer can equal faster. Also check that you don't have too much weight forward keeping the front of the tubes submurged. Shift stuff back a bit and there are just a whole lot of triming tricks for the motor. Also does his have a shroud in front of the motor and yours not?

Mine des also, So I will assume there is no performance enhancements that I can do? I know its not a drag boat or anything, but because of the lake we have a permanent camp site on we are stuck with only 25hp. I'm just thinking it would be nice to have atleast 35+ hp. Or am I just looking at this work and need to figure out a way to get more thrust? Guess what I'm really trying to figure out is how to go a little fast on the water?

 

[bigpimpin]

Re: Need more power.

I don't know if this is the answer but, while reading on the boat design forum I learned that Longer can equal faster. Also check that you don't have too much weight forward keeping the front of the tubes submurged. Shift stuff back a bit and there are just a whole lot of triming tricks for the motor. Also does his have a shroud in front of the motor and yours not?

I really don't have any weight in the front at all. Other than the whats there? I did however just install a major upgrade to the stereo system. Added several amps, subs, an multiple midrange speakers. All the extra weight (subs, an Amp's) are mounted in the back? will this extra weight possibly help?

 

[bigpimpin]

Re: Need more power.

...keep your tubes clean on the bottom and maybe install some underskinning (aluminum sheets under the deck to keep water from splashing back and causing slow down). Also, you may be able to find a prop shop near you who would be willing to "loan" you a few props to help dial-in the correct pitch for your setup.

Would you happen to know what pitch is recommended for the 25hp mercury efi 4 stroke? Should it be 3 or 4 blade? Does that also make a difference?

 

[garbageguy]

Re: Need more power.

I really don't have any weight in the front at all. Other than the whats there? I did however just install a major upgrade to the stereo system. Added several amps, subs, an multiple midrange speakers. All the extra weight (subs, an Amp's) are mounted in the back? will this extra weight possibly help?

How much weight was added? Extra weight will not typically help a boat go faster.

 

[BigDfromTN]

Re: Need more power.

Would you happen to know what pitch is recommended for the 25hp mercury efi 4 stroke? Should it be 3 or 4 blade? Does that also make a difference?

Every thing makes a difference in one way or another. There are no set numbers with pontoons especially prop numbers. I changed my prop to a 4 blade as I was having problems with slippage at times. Normally a 3 blade is fine. I see your motor is rated to turn in the 5-6000 range. You might try a prop that is one number lower than what you have now to see. Oddly enough you may get more speed by turning a "shorter" prop at a higher rate of speed.

I did look at Mercury website. The 25 and 30 are in the same family of engine with the same bore and stroke. The 30 is rated to turn a higher RPM and has a slightly heavier weight.(guessing wt diff is power trim as site says 25 don't have it and 30 does) I don't know what the difference is. May be in the injectors or Injectors and computer? You would need to ask a Mercury Marine Mechanic about that.

I also found this test on Mercury's site. Engine Test | Mercury Marine

Get a GPS speed on your boat as it is set up now before making any changes. That will give you a good baseline to work from.

I wonder if the other fellow has added larger carbs/injectors to up his actual HP???

 

[bigpimpin]

Re: Need more power.

haha I know it doesn't make it go faster, I prob added around 100 pounds total, maybe 150? Will that have a big affect you think?

 

[bigpimpin]

Re: Need more power.

Thanks for the advice! Ill check into all that. I don't believe he did anything but I'll be sure to ask him... Again Thanks

 

[ElGringo]

Re: Need more power.

Is more than half the diameter of the pontoons under water?

 

[MH Hawker]

Re: Need more power.

Hello Everyone,

This is the 1st time I have ever posted on forums an I'm hoping to get some expert advice

I have a 2013 Xcursion X20C pontoon boat with a 25hp 4 stroke efi Mercury. The lake we stay at only allows 25hp max, I need more. Is it possible to increase to 35 or 40hp without cheating an buying a new motor an changing stickers. "not my thing" I run open around 5000 rmp's. but I feel like i am setting still in the water. My buddy has a 25hp 2 stroke from 1987, its a 24 foot Harris and he blows by me every time. Embarrassing really haha.... Any advice? Thanks

The short answer is no the 4 strokes are a lot like car motors it takes more than bolt on parts to change it and no one makes those bolt on parts unless you want to make a NOS kit for it. The Johnson and rude 2 strokes can easily be changed some what the merc no.

a 2 strokes fire ever stroke while a 4 stroke fires ever other stroke and a 4 stroke due to the extra moving parts has more internal drag, I am also on a limited HP lake to 9.9 and i run a 2 stroke and i pass 90 % of the other boats.You can optimise its performance though by adjusting the motor for maximum bit in the water and changing props around the get full WOT RPM. In my case i case out of the no wake zone point it and go to WOT and open a beer and enjoy the ride.

I wouldn't suggest re baging a larger motor the DNR people often inspect and they go by serial numbers and your fined or your boat is impounded and sold at auction.

 

[richard.prince]

Re: Need more power.

I have been told that mercury uses the same engines for several different HPs and the difference is in the tuning.

 

[Scott Danforth]

Re: Need more power.

if your motor is too low in the water, it will slow you down. adding weight in the water will dip the motor lower, slowing you down.

when your running flat out, take a look at the anti-cav plate. it should be near the surface of the water. if its too deep, you will be slow.

raise your motor to get the max out of it, then play with props.

Also, as BatDaddy stated, skinning the underside of the deck helps

 

[WaterDR]

Re: Need more power.

Uneless something is REALLY jacked-up, nothing you can do is gonna make any difference. You could toss a zillion bucks in that motor and it won;t matter much. At that power level and at that speed doing things like underskinning would have very poor ROI. Sounds like you have the correct prop...perhaps changing to something that will get you in the 5500 range would help...depending on the max rpm recomendation for that motor. Otherwise, the only good option for speed is changing lakes.

But, I would not be too upsept about your buddy blowing by you with his 25. Arguing over who's 25 hp motor is faster is really sort of a non winning battle. I used to have a motor like this. i am not poking fun at you, rather having empathy.

 

[MH Hawker]

Re: Need more power.

Be glad your on a 25 hp lake and not a 9.9 like i am.

 

[funk6294]

Re: Need more power.

Can you add a second 25hp motor?