Yamaha 115hp 4 stroke 20mph only????

kyong1

Seaman Apprentice
Joined
Jan 24, 2011
Messages
45
My Carolina skiff 198DVL only ride at 20mph at full throttle.. With a 115hp 4 stroke 2011 I feel Yamaha should go faster... change d sparkplugs; fuel filters; all oils. What could the community recommend. My appreciation thanks 😑 inshore fishing
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
It really helps to know if this is a new problem. Did the boat go faster in the past and began slowing?

Time for basics - Fresh fuel, check compression and check for spark on all cylinders to begin with.
 

kyong1

Seaman Apprentice
Joined
Jan 24, 2011
Messages
45
Not a new problem....however like i said I do inshore fishing. The boat was bought used and never needed to go faster until I just decided to peak out rpm and accelerate r all the way forward 22mph max??? MPH Gage 60mph.....
saywhaa 😎
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,927
What rpm's at wide open?
What size prop?
Damage on the prop?
Does it sound like the motors revving up but the boats not moving? Damaged hub in the prop.
Remove the prop and look for rubber pieces, then draw a line across the hub and prop and go for a ride.
Inspect the prop and see if the line's moved. Spun hub.
 

kyong1

Seaman Apprentice
Joined
Jan 24, 2011
Messages
45
Well mark the pro. And went for a long ride. Max at 23.5 at 4800 rpms. Checked the pro after wards and seems like I need to rerun when weather gets better permanent marker didn't work..😑
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
If motor is fuel injected then you could have a plugged injector screen causing loss of power on that cylinder....
 

kyong1

Seaman Apprentice
Joined
Jan 24, 2011
Messages
45
In the process in draining fuel tank and disassemble vst when weather's get better, that should to it.,..,,😎
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,501
A buddy has the 115 on a 21DV. Boat runs mid to upper 30’s

Your a 1,000 rpm shy of WOT. Checked compression? What prop are you running?
 

kyong1

Seaman Apprentice
Joined
Jan 24, 2011
Messages
45
A Solas 13 1/4x17...which came with Carolina 198 DLV 2011... compression will my last choice... Thanks 😑
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,927
Yo sure the tach is correct?
They sell a Tiny Tach just ground the wire and wrap another around the plug lead and compare the readings.
 
Top