First Boat

[protour]

Hello all,

I bought my first boat this weekend. The dealer said they compression tested it, and it was fine. My question is top speed. It is an '89 19 foot astroglass fish/ski with an '89 evinrude xp150, 14.25" prop/21 pitch. At WOT, it only did 40.2, verified on my GPS. Does this sound right, or should I look into cleaning out the carbs or something else? The prop does have a couple good dings, and the bottom thingy (sorry for nomenclature) below the prop is bent about 2 -3 degrees at the last 2 inches of the tip. Thanks for any help.

 

[kenmyfam]

Re: First Boat

Welcome to iboats.
Give it a decarb, get the prop repaired are both things to do that are beneficial even if it does not make it go faster. What is the rpm at WOT ??? is it trimmed correctly ?? Just a couple of things to start the ball rolling. There are many other things to diagnose as well but the rpm thing is a good start. How is the condition of the floor ?? you could have water soaked flotation foam adding considerable weight.
By the way i think that the bent thingy is the skeg.

 

[protour]

Re: First Boat

I wanna say it was at 4200 RPM. I messed with the trim until it had the highest RPM and was planing level. How can I determine a water soaked flotation foam? Can the skeg be easiyl changed out, and by looking at it, it seems it might make the engine unstable at high speeds, no? Thanks for your assistance.

 

[hitace]

Re: First Boat

always rember you are always moving faster on the water

 

[kenmyfam]

Re: First Boat

I wanna say it was at 4200 RPM. I messed with the trim until it had the highest RPM and was planing level. How can I determine a water soaked flotation foam? Can the skeg be easiyl changed out, and by looking at it, it seems it might make the engine unstable at high speeds, no? Thanks for your assistance.

4,200 rpm sounds way low to me but there will be an expert along shortly that can tell you exactly what your WOT range should be. I am guessing but would expect it to be at least 5,000 rpm. May need to drop the prop pitch. Post some pictures of your outfit showing the outboard on the transom and the relationship of the cavitation plate on your motor to the bottom of the hull. A picture can be worth a million words.

 

[tashasdaddy]

Re: First Boat

there is no easy way to change the skeg, don't try to straighten it or it will break off. it takes a prop. there are thousands of motors with bent skegs, soundn't hurt performance. may effect slightly steering which can be corrected by moving the back of the trim tab the direction the boat is pulling. to tell if you are carrying extra go to NADA boats, look up your boat, motor, trailer, they have the weight, as they came out of the factory, add all gear, fuel etc. have the rig weight at a public scale. this will tell you if you are holding water.

 

[studlymandingo]

Re: First Boat

Verify your WOT RPMs. 4200 is VERY low for that motor. Could be a number of things causing this. I would also verify the compression test for myself.​

 

[protour]

Re: First Boat

I hope I'm posting these pics right.

 

[protour]

Re: First Boat

The 4th picture was a connector that is connected to nothing....still looking around that area for something to plug it into. Sorry for the pics being small...wasn't sure what size would work, but I can try to make any of them bigger.

 

[tashasdaddy]

Re: First Boat

the prop needs to be replaced or reconditioned, the trim tab could be replaced. that little bend in the skeg, should not effect anything. if yu clik on the pics, they enlarge.

 

[Rudy Brown]

Re: First Boat

As other posters stated, verify compression first. And Whoa, deep six that prop, or get it fixed, (I'd get rid of it). That prop isnt helping things one bit. That motor should have no problems turning 5500 rpms at WOT and speed should be high 50's. Pitch seems right for the motor. Anyway, compression first, prop second then verify the tach is right for the motor and its on the correct setting. (should be set on 6 on backside) Get back to us with them compression numbers.

 

[studlymandingo]

Re: First Boat

New prop!!!

 

[protour]

Re: First Boat

Thanks for the starting points. There are no number settings on the back of the tach, and it looks original. I will get the compression numbers as soon as I can.

 

[protour]

Re: First Boat

K, here are the compression numbers with a cold engine, muffs connected/running, and safety lanyard thingy pulled.

Port (top to bottom): 80, 82, 70
Starboard (top to bottom): 80, 82, 88

Looking into getting a new prop now....gonna go aluminum for first one, and will stick with 14.25/21.

 

[studlymandingo]

Need some higher numbers.

Need some higher numbers.

First off, you should always test compression at operating temperature, but it sounds like you have some pretty low numbers. You should be over 100 on each cylinder with no more than a 10% variance between cylinders. There is the possibility that your rings could be carboned up and sticking, in which case a thorough decarb can help.

Mix 1 can of SeaFoam with 1 gallon of gas; run your motor on muffs to reach operating temperature. Turn off the motor, disconnect the fuel line and attach it to your can containing the SeaFoam mix. Restart the motor and let it run for a while pulling in the SeaFoam mix; you will get a lot of smoke at this point. Cut the ignition and let it sit with the SeaFoam inside for several hours then start it back up with the SeaFoam mix; you're going to have lots and lots of smoke with black crud coming out of the exhaust. Let it get back to operating temperature, and I would personally let it sit for awhile again.

After you have done this, get the motor up to operating temperature once again; recheck your compression.

Another thing would be to verify that your compression tester is functioning properly by checking against another tester. It would be good to see numbers above 110 across the board.

You said the dealer checked compression and it was fine; how long have you had the boat now? I would be looking to the dealer for some support here.​

 

[studlymandingo]

About the Prop

About the Prop

Also, you need to find a dealer that will let you test a couple of props; once you have the motor running properly, you are going to want a prop that will spin that motor up over 5200 RPM at WOT.

 

[roscoe]

Re: About the Prop

Re: About the Prop

And take that hydrofoil off the lower unit.
Get the motor running right.
Get the motor mounted at the correct height on the boat.
Should perform well enough without the hydrofoil if it is set up right.

Hydrofoils will all to often hurt performance.

 

[jpg0511]

Re: First Boat

I have a 1990 18ft Hydra-Sports fish and ski with a 150gt on it and a 14 1/2 X 22p prop. When I first got the boat the boat was slow to plane and had a top speed of about 40mph. So I first removed and cleaned the carbs. That helped some. Done a compression test also an they were 90 to 95 psi. Then after reading more on here I checked to see if all the cylinders were fireing by pulling one wire off at a time while the engine was running and found one was not. I would have never thought the engine was running on only 5 because it ran smooth and started great. Replaced the power pack and the motor was running alot stronger. After that the boat was running close to 50mph. Then I read about de-carbing the motor with seafoam so I tried it. Just followed the instruction listed above. Re-tested the compression and they were all 100 to 105psi. The boat is running close to 55mph and the motor is smoother than ever. My boat is very simular to yours. It weights 1450 acording to NADA and it looks like your should weigh about 1550 or so.I also was new to larger outboards and boat like this when I got mine a few months ago. I would say order you a manual. Then get some beer and spend some time reading here and getting some ideals on what to check. Jason

 

[protour]

Re: About the Prop

Re: About the Prop

Do I need to fill the holes left behind when taking the hydrofoil off, or will they be fine staying there? What would you fill them with?

 

[studlymandingo]

Re: First Boat

Put a piece of tape on the bottom of the hole, then fill the hole either with some good epoxy or some 3M 5200. I would do this after I got the compression issue straightened out.


Do you have any kind of warranty through the dealer?​