From 25MPH to 15MPH in 3 months...

Swordsman

Seaman Apprentice
Joined
Mar 3, 2011
Messages
44
about 3 months ago i remember when wakeboarding on 5000RPM, trim almost all the way up to make the wake bigger and crisp, i checked the speed with GPS and it was 23-25MPH which is more than enough for wakeboarding
now, after fixing my slipping propeller , went wakeboarding today with some friends that also used to come with me 3 months ago
the speed was wayyyyyy lower, wake was full of white wash and i could actually feel myself sinking in the water rather than sliding like it should be
i wasnt the only one, every one of my friends when wakeboarding signaling me to accelerate also noticed that lack of speed, the throttle was wide open for sure but nothing, it reached almost 5000RPM but speed was low
checked it on my GPS , 15MPH tops!
dove under the boat to check for fouling and stuff on its body, nothing that should cause this dropped MPH
im very depressed, my only use for this boat is wakeboarding and where i live it very rare for the sea to be as flat as it was today :(
what to check ? RPM is almost as usuall, 200-300RPM might have dropped from 3 months ago, engine sounds normal...
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: From 25MPH to 15MPH in 3 months...

What is the motor in question?

Fixing slipping propeller - did you have it repaired or replace it with the exact same diameter and pitch?
 

Swordsman

Seaman Apprentice
Joined
Mar 3, 2011
Messages
44
Re: From 25MPH to 15MPH in 3 months...

What is the motor in question?

Fixing slipping propeller - did you have it repaired or replace it with the exact same diameter and pitch?
oh sorry its a MERCURY EFI 115HP 2006
it was repaired, replaced the plastic drive sleeve which was bent
also ive marked the metal hub and the prop to check if it is slipping, checked it today, no slipping
 

jbjennings

Captain
Joined
Jul 18, 2007
Messages
3,903
Re: From 25MPH to 15MPH in 3 months...

It sounds to me like someone either accidentally switched props or repitched it wrong. OR, you have got some water under the floor. Is it trimming all the way up and down properly? Have you checked compression, and made sure the engine is cooling properly. No other ideas here.....
JBJ
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: From 25MPH to 15MPH in 3 months...

I find it hard to believe your RPM would stay the same, but speed would drop 40% with the same prop. Any chance the boat is getting waterlogged?
 

Swordsman

Seaman Apprentice
Joined
Mar 3, 2011
Messages
44
Re: From 25MPH to 15MPH in 3 months...

well i feel stupid, all this skiing is kinda new to me, never thought weight is so sensitive in boating
last night me and my friend were on the boat, WOT 23-25MPH the wake was very crisp and high with the motor trimmed way up
i was so happy that i slept 4 hours and woke up and gathered 2 friend and went wakeboarding, never had this much fun :)
it was performing like a champ, i even had to tell my drive to slow down cause it was way fasttt
i guess 2 more 75kg ppl on the boat slows her way down :/
i dont really care as long as i can be sure nothing changed on my engine is still working properly like it has been on the last 3 years, gonna spoil it soon with some new oil and filters :)
 
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