struggling to get on plane

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stretch84

Cadet
Joined
May 25, 2010
Messages
14
Im new to this boating thing so bare with me. I have a fletcher arrowflyte (in picture) with a 1983 70 hp evinrude. I am having trouble with getting up on plane while trying to water ski . I have replaced the carbs with the new version with low speed adjustment help a little but not enough they are spotless!! new fuel pump kit and all hoses new plugs, compression is good all around 135 Somebody has suggested that I may be over propped now this where I get lost! From what i can work out i have a 14 x 17 prop iv no idea what this means but can I change it to help with acceleration rather than top speed im more interested in water skiing than racing

my head a wrecked :mad::mad:

please help

steven
 

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mikesea

Lieutenant Commander
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Oct 1, 2006
Messages
1,830
Re: struggling to get on plane

Yes you can get a different prop to help,assuming your mechanical part engine wise is OK.There is a forum just for prop questions,might get better help there,BUT,there are many aftermarket companies that make speciality props for skiing
 
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bigpoppakdog

Chief Petty Officer
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Jul 9, 2008
Messages
437
Re: struggling to get on plane

Looking at the closed hull boat and having a 70hp motor, you are probably going to have problems getting on plane. I had a trihull with a 85hp merc and had trouble getting on plane unless I put people in the front of the boat. It also appears you have some sort of pylon, which is good. I would say if you could put some weight in the bow you will notice a major difference. I had a closed bow boat years ago that I put some weight in the front and I could water ski and pull a tube. It only had a 50 hp motor also. I don't think from the sounds on the video that anything is wrong with your motor.
 
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stretch84

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May 25, 2010
Messages
14
Re: struggling to get on plane

Im assuming the white fines sticking out the side in the picture are assuming are hydrofoils or a really bad version , also what did you use as weight for the front i dont have a big hole to get up there its a tight squeeze
 

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chevinrude

Seaman
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Jun 13, 2010
Messages
53
Re: struggling to get on plane

Yes thats what those are on your boat, albeit pretty flimsy ones it seems.

With no additional weight in the bow, and 5 people, two coolers, a grill and various other things (approximately an additional 1000#), I am planing out in slightly under 5 seconds. This is with no additional modifications, just that hydrofoil. Before installing the hydrofoil, I was taking almost 10 seconds to plane.

Another thing is that your motor could be mounted too high or low on the transom. Or it could be as simple as trimming up the engine a little when at WOT.
 
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stretch84

Cadet
Joined
May 25, 2010
Messages
14
Re: struggling to get on plane

Ya i was just seeing if less weight in the boat would help it didn't I'm gonna get better foils and try get some weight up the front cheers for the input lads
 
kenmyfam

kenmyfam

Supreme Mariner
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Messages
14,392
Re: struggling to get on plane

What is your WOT RPM without a skier ????
 
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bigpoppakdog

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Re: struggling to get on plane

stretch84 said:
Im assuming the white fines sticking out the side in the picture are assuming are hydrofoils or a really bad version , also what did you use as weight for the front i dont have a big hole to get up there its a tight squeeze
Click to expand...

How about the tube sandbags?
 
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bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,306
Re: struggling to get on plane

first of.

id say that the boat motor combo is on the very weak side for pulling a skier!!!!!!!!!

70 hp is nothing..that said

do you have a tach?

if so what rpms are you turnign at WOT normally when you not trying to pull a skier?????

id say that a 17 pitch is awful steep for that combo!!!!!

I bet you need to get down to a 13 pitch...or at leasy a 15 S/S

I picked up a 1988 70 hp and it has a 13-3/4 X 15 Stainless Steel prop on it..

the motor looks to be mounted at the right hieght

what trim angle are you at????

good luck

bob
 
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stretch84

Cadet
Joined
May 25, 2010
Messages
14
Re: struggling to get on plane

Cheers for the input bob I don't have a tach at the moment it's on order hope to have it soon I'm fairly new to the boating scene learning as I go I have adjusted the trim angle is ever way possible I have the motor running as sweet as possible the boat is only built to take a 75 hp motor so I can't be far off the hp required I'm def gonna try new prop as soon as I get the tach to see what rpm it's running at wot at the moment
 
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bigpoppakdog

Chief Petty Officer
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Messages
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Re: struggling to get on plane

I had a 14ft chrysler cadet with a 50hp suzuki. Closed bow. I can't remember for sure what I used, but I know I had to put weight in the front in order to ski and tube behind it. I am confident that if you do this you can easily water ski behind your 70hp. Watching your video again I noticed when you did start to get on top of the water the motors rpm's starting to go up and you would have been off and running. Also noticed by appearance of your wake, the motor is trimmed down pretty deep in the water. But with it being only a 70 hp, not sure if trimming it up will do you again good?

Oh yeah, I now remember what I used. I took one of my 45lb weightlifting plates and stuck it in the front. This made a night and day difference when it came to skiing and tubing. Add the weight and take another video so we can see the difference.
 
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dazk14

Ensign
Joined
Jul 22, 2008
Messages
966
Re: struggling to get on plane

Fastest acceleration will occur when motor is in lowest trim position, but not best for top speed.

Those 3 cylinder models had poor low end power, but great on gas.

A 15" modern designed (progressive pitch) prop would make a world of difference.

Smart tabs would help as well.

An aluminum 15" Solas Amita is a good prop if overseas pricing is like the USA...$74 delivered from iboats.

My next choice would be a turning point hustler ~$100 del...

Good stainless props start at around $200.

You can run that motor up to 5800 RPM's without it flying apart.

One trick we used to do years ago(when I was in my 20's) is leave the rope slack ~5-10' and gun the engine.:eek: It worked well and I was running a 21" prop on a 70 and starting on 1 ski!!!

With the 15" prop - you won't need the craziness.
 
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dazk14

Ensign
Joined
Jul 22, 2008
Messages
966
Re: struggling to get on plane

I just re-read your original post and if your prop info is correct - 14" diameter - that would be a large hub prop.

Please measure the hub diameter and report back.

The overall equation is the same. A 14' diameter is really too much for that motor.
 
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tlzimmerman

Petty Officer 3rd Class
Joined
May 21, 2010
Messages
82
Re: struggling to get on plane

You may want to focus on moving weight to the front of the boat if at all possible, instead of just adding weight. Adding weight to the front is better than nothing, but if you can move a battery, fuel tank, anchor, anything like that to the front, its better than just adding weight. You are trying to move the balance forward, which can be done by both adding weight to the front, and removing it from the rear.

I think you look overpropped too, but I know very little about that and will defer to the ole experts on that one.
 
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bob johnson

Rear Admiral
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Messages
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Re: struggling to get on plane

dazk14 said:
I just re-read your original post and if your prop info is correct - 14" diameter - that would be a large hub prop.

Please measure the hub diameter and report back.

The overall equation is the same. A 14' diameter is really too much for that motor.
Click to expand...



I have a 14 x17 aluminum prop...they came from omc on many motors Mine was on my small gear case V4 90hp (1997) but it fits the 70 hp as well...I took the 13-3/4" X 15 off the 70 and used it on my 115 hp V4( also a small gear case)...there is room for almost 15.5" on my V4's even though it is impossible to find a prop that big with a 4" dia hub body( small gear case LU)

the prop selection for the small gear case is really limited i have found

bob
 
kenmyfam

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: struggling to get on plane

stretch84 said:
Im new to this boating thing so bare with me. I have a fletcher arrowflyte (in picture) with a 1983 70 hp evinrude. I am having trouble with getting up on plane while trying to water ski . I have replaced the carbs with the new version with low speed adjustment help a little but not enough they are spotless!! new fuel pump kit and all hoses new plugs, compression is good all around 135 Somebody has suggested that I may be over propped now this where I get lost! From what i can work out i have a 14 x 17 prop iv no idea what this means but can I change it to help with acceleration rather than top speed im more interested in water skiing than racing

my head a wrecked :mad::mad:

please help

steven
Click to expand...

OK, so where are you from ???
That canal barge in the background of your photo is a dead giveaway !!!
 
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