New Sea-Pro porpoising

Dan180cc

Seaman Apprentice
Joined
Jun 4, 2003
Messages
40
Hello, I recently purchased a new Sea-Pro 180 center console with a Johnson 140 4 stroke.I chose the boat and motor after reading about them on this forum and learning alot from the information posted here.I have now completed the break in period and can now take it to full throttle. I have encountered a problem that I would like to get some advise on before I return it to the dealership.<br />My boat is porpoising at all trim positions except full down or close to it. The negative trim seems to load the motor down a little and if I raise the trim up the porpoising starts slowly and seems to get worse. I have also noticed that the motor RPM's will go above the Max listed in the manual of 6200 and the motor will begin to slow down as if it is missing, I have only noticed this when I am alone in the boat. When the wife and kid are with me the rpm's dont seem to go that high.<br />My dealership is going to check my boat on tuesday but after talking to them Im not really sure they know what to do. They have mentioned a hyrofoil fin but I am concerned about voiding of my warrenty if I start drilling holes. Any advise would be welcomed. The rest of the information on my boat is as follows.<br /><br />18 ft center console Sea-Pro 180 (1500lbs) 2003<br />Johnson 140 4 stroke (421lbs) 2003<br />Prop three blade 14x17 alu. oem<br />WOT 47mph negative trim at 6200 rpm's.<br /><br />My boat has a deep v hull with a flat area at the center of the transom. The bottom of the deep v is about 2 inches below the cavatation plate. My motor is mounted one hole up from the full down position. Could this problem be due to the extra 90 LBS of the 4 stroke engine?<br /> Thanks Dan.
 

lonewolf5347

Chief Petty Officer
Joined
Jun 11, 2001
Messages
529
Re: New Sea-Pro porpoising

Dan:Just pick up the same boat out of va. last week from ed's marine superstor 2003 sea pro 18 ft center console with a 90 hp yamaha will have it in the water on monday for the first time .I will let you know what I think after the test run,otherwise I think from what I seen so far getting it set up the last week the boat is well made for the money.I am going to call them on Monday and see if they have a little better or a up grade to there wiring diagram so simple really hard to understand.
 

lonewolf5347

Chief Petty Officer
Joined
Jun 11, 2001
Messages
529
Re: New Sea-Pro porpoising

dan: what you can look for is weight distribution on your problem
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: New Sea-Pro porpoising

Hi, Dan.<br /><br />Porpoising is caused by the bow trying to rise too high for the engine to keep it up.<br /><br />Common causes are too much weight aft and too much trim-out.<br /><br />Your 140 only weighs 410lb, less than most engines in that power range.<br /><br />Hydrofoils do not void warranties, unless there is a problem with the AV plate that you drill, and they do help control porpoising.<br /><br />If you over-rev that engine the ECU takes over and limits rpm. That is probably the "missing" you notice. I suspect that you are ventilating your prop.<br /><br />Your engine may be mounted too high. Have them take it down one hole.<br /><br />Good luck. :)
 

Mikedg

Petty Officer 2nd Class
Joined
Sep 3, 2002
Messages
131
Re: New Sea-Pro porpoising

I wouldn't go with the Hydrofoil to fix the problem, they add to much drag. If the engine is rigged properly, i.e. the hieght on the transom is correct and the weight is distributed properly in the boat and you still have the problem, I would look at adding trim tabs.<br /><br />You might look at Smart Tabs as a low cost solution. www.nauticusinc.com
 

Dan180cc

Seaman Apprentice
Joined
Jun 4, 2003
Messages
40
Re: New Sea-Pro porpoising

Lonewolf, JB<br /><br /> I thought about weight distribution but there is not much you can move in a center console boat. I have 2 batteries under the console now and with the wife sitting on the front console seat it still does it but not as bad.<br /> But your idea has got me thinking, I am carrying 1/2 a tank of gas about 20 gallons. My tank is under the floor in the console area. Could this gas moving back and forth be causing the prop to break loose?<br /><br />JB, I could see if they would drop the motor to the bottom hole this may add more leverage to raise the bow. When at rpm ranges below wot it bounces also I cant really tell for certain but I donot think the prop is venting I say this because the rpm's dont serge when the porposing starts and I dont have any to just a little trim out when this happens. <br />thanks Dan.
 

jocko_nc

Seaman
Joined
Mar 18, 2002
Messages
65
Re: New Sea-Pro porpoising

Reading all this, I am suspecting your motor may be too high as well.<br /><br />As far a weight, Sea Pro specs 115 hp as the "recommended", with 140 hp as max. With a 4 stroke, I assume you are at the high end of weights figured for that boat. 410 lbs is not too bad, though it is slightly heavier than my 150. Regardless, you do have the heaviest "allowable" motor per the manufacturer specs... ???.<br /><br />FWIW, my 150 Yamaha / Sea Pro 210 does 42 WOT at 5200 rpm. I am a bit overpropped, but that is fine w/ me. Heavier boat w/ tee top and canvas. I would think your 18 ought to break 50 mph easliy at that rpms. Perhaps that indicates motor is too high as well?<br /><br />Let us know how it goes.<br /><br />jocko
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: New Sea-Pro porpoising

I don't agree with the idea that hydrofoils add drag.<br /><br />By moving the center of contact aft they often actually reduce contact area and drag.<br /><br />My Suzi DF70 powered Montauk actually picked up almost 1mph when I added the SE Sport 300. It planes quicker and at lower speed, too. I also mounted my AV plate even with the keel to get rid of porpoising.<br /><br />Good luck.
 

jocko_nc

Seaman
Joined
Mar 18, 2002
Messages
65
Re: New Sea-Pro porpoising

Looking up some more data, the weight of that motor is the same as mounting a 200 hp 2-stroke. ???. Was the 2003 18 foot designed with 4 strokes in mind? I know the "21" foot was new for 2003, all previous years were "old" designs and would have been assumed motor to be a 2-stroke.<br /><br />That may be a lot of weight back there. A good fin may be a big help.<br /><br />jocko
 

boaterntexas

Petty Officer 1st Class
Joined
Feb 4, 2003
Messages
254
Re: New Sea-Pro porpoising

PORPOISING? Is this when the boat bounces? Just wondering.
 

chris in va

Chief Petty Officer
Joined
May 4, 2003
Messages
410
Re: New Sea-Pro porpoising

Porpoising is when you're trying to get smoothly up on plane and the boat bobs up and down instead. Think of how a dolphin jumps in the water and you get the idea.
 

jomac

Petty Officer 2nd Class
Joined
May 1, 2003
Messages
195
Re: New Sea-Pro porpoising

I have to go with JB on this one Hydrofoils are the BEST single low cost thing you can do for a boat(Stringray brand on mine) my 19 CC Bayliner had one on the old Force motor boat drove great at all speeds, After replacing the old motor with a new 115 Ocean Pro, first trip out was NOT fun i could not keep the boat in the water, wouldn't plane at low speeds either Needless to say i went straight to Wal-Mart ,bought a new String Ray brand foil, Boat is back to it's Old self ;) P.S. My top speed improved with the Hydrofoil! :cool:
 

Dan180cc

Seaman Apprentice
Joined
Jun 4, 2003
Messages
40
Re: New Sea-Pro porpoising

jocko,<br /> For what is worth, my dealer told me he has sold several 180cc's with 4 strokes on them. I do know that the 140 actually weighs less than the 90hp or the 115 4 strokes. I guess the best thing to do is to try to get them to lower the motor all the way down first and if that is not enough go with the hyrofoil. Do you think a different prop may make a difference or am I getting to far ahead of myself. I tried to get someone on the phone at SEA-PRO but I didnt get passed the little girl on the phone. Took my number, never called me back. Thank to all of you for your time. Dan.
 

lonewolf5347

Chief Petty Officer
Joined
Jun 11, 2001
Messages
529
Re: New Sea-Pro porpoising

dan:had a chance to dip the boat to day ,what I found was trying to get up on plane.Was running around 3200 on the tach.yamaha states breakin first hour around 3000 rmp or more to get on plane.One of my problems I think was weight on board ,seems everybody wants to take a ride and I do think I was close to carrying weght max. 4 adulta and my grandaughter went along for the ride.Otherwise had really no problems going to try on Friday again me and the wife only and see what happens.I myself today did call sea pro on a question about if the dealer mailed in the warranty card got a little of a cold reply from the girl who took the phone call.
 

Dan180cc

Seaman Apprentice
Joined
Jun 4, 2003
Messages
40
Re: New Sea-Pro porpoising

LONEWOLF,<br /> I noticed the same thing I had to run at 4000 rpm to get it to plane out then backed it down to 1500 to 2500 for the next several hours. Im done with the breakin now. I have run about 12 hours and have gone to wot several times I really like the boat and motor so far and its very different from my old boat. This 140 4 stroke is burning about 1 gallon per hour the way I drive it and maybe a little more now that I can run a liitle faster. Keep me posted on how yours works out.<br /><br />I going to take mine to the dealership tomorrow<br />so they can check the porpoising problem I have <br />run into. The problem seems to be at its worse when Im at 3/4 wot, 5200 rpm. I have to keep the trim at all most bottom. JB, seems to think a hyrofoil may be the way to go. Ill see if they will drop the motor down first. thanks again<br />Dan.
 

rdmoore

Cadet
Joined
Jun 9, 2003
Messages
14
Re: New Sea-Pro porpoising

True Story. A few years back , I was looking for a smaller boat than my<br />Four Winns cuddy, mainly for taking the family out on small lakes for water<br />skiing and tubing. After looking around a bit, I purchased a Stingray 180<br />RX bowrider. It seemed to meet our space and performance needs and seemed<br />like a real value for it's cost. And it was, except for one glaring fault.<br />At anything less that W.O.T and speeds below 35-40, it would porpoise<br />horribly unless you kept the trim fully down. Because you had to drive with<br />bow always plowing the water, instead of planing as it was designed to,<br />cornering was very unpredictable, gas mileage suffered and handling in<br />general was poor. It got to be so bad, my wife refused to drive it when I<br />wanted to ski. Having owned many other boats that you could trim at any<br />speed (once on plane), I knew this was not correct and tried to work with<br />first my dealer, then Stingray the company, to get this corrected. To make<br />a long story short, lets just say they both were an absolute joke. All I<br />had to show for months of effort of trying to go through the proper<br />channels, was countless unanswered phone calls and e-mails, wasted trips to<br />the dealer, money wasted on another prop, a lot of frustration and the<br />first hand knowledge (after trying other 18 & 19 foot Stingrays out) is<br />that they all porpoise just as badly! Many other disgruntled owners had<br />also contacted me with this same issue, after I started asking for help on<br />various boating forums. But just as I was convinced this is a flaw in the<br />design and was putting the boat up for sale, I learned of the smart tabs<br />from Nauticus. I contacted the company, who was very helpful and promised<br />they would completely fix my porpoising problem. After all I had gone<br />through with the shallow answers and promises from my dealer and Stingray,<br />I was extremely skeptical, but I went ahead and ordered a set, figuring it<br />was a lot cheaper than buying another boat. Got them a few days later and<br />installed them in about an hour.<br />Let's just say the results were far beyond my highest hopes. There is<br />absolutely no more porpoising. None whatsoever, no matter what speed or<br />trim the motor is at. Additional benefits are that the thing planes almost<br />instantly, it virtually doesn't even lift the bow at all! You feel like<br />you're in a car, not a boat when you take off! Because of this the hole<br />shot improvement is amazing. Heavy slalom skiers I could not pull out of<br />the water previously, now are no problem. Gas mileage is improved and the<br />thing corners predictably and rides much better. I even called the owner of<br />the company and thanked him personally. That was 2 years ago, and I can<br />truly say I am now 100% satisfied with this same boat I was so disgusted<br />with before the smart tabs installation, and can't even imagining using it<br />without the smart tabs. I hear so much about boaters looking for<br />performance improvements with expensive engine and prop modifications, <br />or complicated hydraulic or electric trim tabs, <br />when they could just add a set of these and get better performance<br />improvements (except top speed, that was not affected) at a fraction of the<br />cost. Several of my boating friend have installed them after they heard of<br />my success, with similar positive results. So go ahead and give them a try,<br />you won't regret it. Feel free to e-mail me if you have any questions.
 

rdmoore

Cadet
Joined
Jun 9, 2003
Messages
14
Re: New Sea-Pro porpoising

Lonewolf, check your e mail, my address is there. Glad to help out. Randy M.
 

boating brad

Petty Officer 1st Class
Joined
Jun 7, 2003
Messages
201
Re: New Sea-Pro porpoising

hey dan180cc it could be important to know that JB said he'd drop it down one hole not to the bottom hole. ps. hydrofoils rule!
 

Dan180cc

Seaman Apprentice
Joined
Jun 4, 2003
Messages
40
Re: New Sea-Pro porpoising

Well I Took my boat to the dealership today and they put it in there test lake to see what they could find. Three of there boat tech's drove it for about 10 minutes and after all was said and done they told me my boat had to be taken to the big lake for some wot runs. They said it comes up on plane good with no venting and will turn hard with no venting They did notice the rpm's seem to go a little higher than they should and they told me they would bring a 14x19 prop to replace the 14x17when they check it. they also may install a hyrofoil if the prop doesnt help. They said the motor was rigged with correct hight already.<br /> I guess I will now something thursday night.<br />If they change the prop, what will this do to the holeshot and topend? The trim tabs may be the way to go but I am not sure about drilling 10 holes in my transom. Thanks for all the replies I will keep you posted. Dan.
 
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