more power better planing 25 ev

[dales33]

hi guys hows it going>
i picked up a pretty tidy little river, estuary harbour rig bout 5 months ago.

it has a 1984 or so evinrude 25 hp on the back.
its pretty reliale and goes not to bad , but it dosnt plane as well as it should.

its on a 12 foot tinnie and should, i feel perfom a bit better, maybe in just expecting to much.

the motor has those dolphin fins fitied and the only fault i can realy find is the props a tad bent, and inbetween the last 2 holes in the tilt bracket seems to be where it wants to sit.
it revs strong out of the water when flushing , checking throtle ect but it seems bogged down, like it isnt set up righ in the water.
any help woulld be apreciated, and yes i require a new prop but i thought i might see what pitches ect were sujested first
.
its not a ski boat, its a recriational fishing boat, i want it to plane well 2 up and achieve as good speed as possible but ill sacrifice that for good planability and low down power.

regards, Dale

 

[tashasdaddy]

Re: more power better planing 25 ev

welcome to iboats. balance the load in the boat, add weight to the bow. get new prop, do tune up on the motor. get engine height set properly. you need to post prop question in the prop forum.

 

[kenmyfam]

Re: more power better planing 25 ev

25hp on a 12 ft tinny seems a lot. It should fly !!!!
Start with optimizing the set up and loading and then look into the motor performance from there. What length shaft is on the motor ???

 

[steelespike]

Re: more power better planing 25 ev

Really need more specific info.Guess the speed??Does it start easily and idle smoothly? That setup should run 32-35 mph.with a light load.If it won't plane there is a good possibility its running on one cylinder.Take one plug wire at a time and ground. See if it will run.My guess is one cylinder is dead and it won't run with the other unhooked.

 

[dales33]

Re: more power better planing 25 ev

Really need more specific info.Guess the speed??Does it start easily and idle smoothly? That setup should run 32-35 mph.with a light load.If it won't plane there is a good possibility its running on one cylinder.Take one plug wire at a time and ground. See if it will run.My guess is one cylinder is dead and it won't run with the other unhooked.

The motor itself starts cold with choke second pull always, or first pull warm, seems o idle pretty well, i might try checking out the cylenders as you said but i pretty sure its running on both, was serviced 3 weks before i got it, the guy had receipts and it had new ngk plus fitted,other than the gas tank and usualy the passenger there general isnt to much weight down the back, but then again i spose its only me up the front so its relitivly even, possibly a bit more at the back.
ill look into all of your sugestions and et some more info for you.

one other thing, ive been offered a 2001 15 horse, i know its smaller but would it perfom better de to newer technology?

thanks again guys

 

[kenmyfam]

Re: more power better planing 25 ev

Did you try what steelespike suggested ??? A motor can sound great with no load on it.
Dump the NGK plugs and put the recommended Champions in it.

 

[dales33]

Re: more power better planing 25 ev

Did you try what steelespike suggested ??? A motor can sound great with no load on it.
Dump the NGK plugs and put the recommended Champions in it.

sorry i got it wrong, it has champion marine plugs in it ,old plugs the previous owner gave me were in ngk boxes.
so as far as grounding the plug lead is concerned should i remove one at a time while running, or try to start it with one lead off at a time, and to i need to slide the plug hood back so i have straight conection between the terminal and the block of will the spark jump suficiantly.
sorry trying not to sound like a lumox but i havnt worked on outboaards before but have pretty decent mechanical knowledge

 

[kenmyfam]

Re: more power better planing 25 ev

Remove one lead at a time while it is running. Make sure you are using insulated pliers or similar though. Best is a electricians fuse puller.

 

[dales33]

Re: more power better planing 25 ev

ok i just removed a lead at a time, its definatly running on both, that isnt to say one isnt slightly better compression
but both are definatly working
and.... ouch

 

[Genonbamagirl]

Re: more power better planing 25 ev

ok i just removed a lead at a time, its definatly running on both, that isnt to say one isnt slightly better compression
but both are definatly working
and.... ouch

Okay - we are going to assume both cylinders are pushing this motor along.

It should run fast enough so you can't stand and pee comfortably off the side even with a horrible prop.

Does it have a working tach? If not, find a shop tach (or borrow one with a small deposit from autozone) and run her out as hard as she will go. WOT for at least a mile on the water. Tell us what the rpm's are. That will help a ton in the diagnostic department.

 

[kenmyfam]

Re: more power better planing 25 ev

ok i just removed a lead at a time, its definatly running on both, that isnt to say one isnt slightly better compression
but both are definatly working
and.... ouch

So it faltered the exact same with each plug wire pulled ???

 

[steelespike]

Re: more power better planing 25 ev

ok i just removed a lead at a time, its definatly running on both, that isnt to say one isnt slightly better compression
but both are definatly working
and.... ouch

You may want to check compression ideal minimum is 100 psi.
and even. If one cylinder is low try a Decarb treatment useing something like Sea Foam.
It won't do as well with a load as say a "big" 14 or 16.But should do well with one or 2 aboard.I had a 18' 25hp tiller steer "tinnie" that planed easily with 6 adults. Same motor on our 15 would barely plane with 4 aboard.

 

[bonzoscott]

Re: more power better planing 25 ev

A 25hp on a 12 ft boat sounds dangerous to me. I have used a '73 25 hp on my 14 ft with 2 batteries and a full cooler up front. It will flip the boat if I twist too quick.. Sounds like carb high speed circuit to me.

 

[ditchen]

Re: more power better planing 25 ev

A 25hp on a 12 ft boat sounds dangerous to me. I have used a '73 25 hp on my 14 ft with 2 batteries and a full cooler up front. It will flip the boat if I twist too quick.. Sounds like carb high speed circuit to me.

depends on the boat and setup. I used to run a light weight 15ft'er with a modified 140hp. All I can say is adrenaline rush. Then to keep the locals talking, I had a 85hp cover

My 14ft grumman jon (AKA called the canoe by most) with 72 25hp. Only thing that bothered me if I fell out I would sink it getting back in.

http://inlinethumb19.webshots.com/7250/2145862380051565062S425x425Q85.jpg

I cannot believe that 25hp with your 12ft boat needs those fins if it is setup correctly and not water logged.