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View Full Version : Lavey Sebring w/Merc 3 Liter NO GO! Help!



Steph Adams
05-22-2001, 09:59 PM
I have a 2000 Laveycraft Sebring with a Merc 3 Liter, Power trim and Jack Plate, power steering. I have used everything from a 21-3 to 24-4 blades and this thing won't go. It either bogs down our just cavitates. I have used the bravo with the vents (all sizes) to no avail. It won't pull any skier and will pull a tube only if everyone sits in the bow and I start real slow. This is also the only way the boat will plane with more than two people in it. I have taken the boat back to Lavey. Lavey had the motor dyno'd and it is putting out power. Merc is sending yet another prop, this will make number 8 on the "try this list". I missed last season trying to figure out something that quite frankly should have been dialed in when I got it. Here it is almost June and at this point I feel like Merc has sold me a "bill of goods". If this last prop that Merc is sending doesn't work I am about to the point where I want out of this mess and I'd never buy another Merc. Everyone looks at this rig and say's WOW that thing should just ROCK and yet....well... Does anyone have any experience with this or a similiar scenario because all mine is good for at this point is to look at it.

ScreaminSunbird
05-23-2001, 06:57 AM
Have you had a mechanic from the dealer go with you to see what you are experiencing??? If its cavitating maybe your motor is raised too high??? I would contact the dealer and have someone spend an hour or two on the boat to see whats going on.

Just a thought.

Liqui-Fly
05-23-2001, 07:03 AM
Know how you feel. Is your jackplate hydraulic? If it is and you know you're deep enough you may want to try an Allison or Johnson foil and possibly a High-5 prop from Merc. Good luck. David

Rickracer
05-23-2001, 07:36 AM
I would have a mechanic, or someone from S&F go for a lake test with you. Where are you at? Maybe somebody from the board can meet you at the lake, and help out. If the motor is making power, you should be able to get that thing dialed in with a knowlegeable observer.

WillyT
05-23-2001, 09:26 AM
How far below the bottom of the boat is your prop shaft at the lowest setting on the jack plate? If it is not well into the water, your hole shot will suffer on that boat. I assumed that you are trimmed all the way in on hole shot? Transom wedges (provide more undertuck/trim in) and some brand of whale tail always helps takeoff. For skiing with my 225 ProMax, I use a 20" pitch 4 blade prop with a small hub. I have a 20'2' Sleekcraft tunnel. This prop lets just enough exhaust bleed over the blades to keep the prop from bogging, but not too much so that it ventilates (I also have the transom wedges and whale tail). My boat comes out of the hole like a rocket with almost no bow rise with this combination. It is so strong, in fact, that I think a 22 or 24 pitch might do almost as well. The 20 will about hank your arms off (but I love it for watersports)! The difference between this prop and my standard 3-blade 21" pitch Merc/Quicksilver stainless prop (which had vent holes drilled in it) is night and day. You would have thought I put a second engine on my boat with the new prop! I got my prop from Ron Hill. I think his son now runs Hill Props. Might be a good guy to call. I just read on a bass fishing board that a COMMON problem with the big block (3.0 liter) Mercs using small hub props (like the Merc Trophy, for example) is way too much ventilation when given full throttle out of the hole (can only get on plane by SLOWLY moving the throttle). A guy wrote in and said the simple fix was to use a $18.00 "blow ring" offered by Port City Propeller. This fills some or all of the gap between the gear case and the prop hub to reduce the exhaust going over the blades. If the prop(s) you have used that ventilate too much are this style, they may benefit from such a restrictor. It sounds like you go from one extreme to the other (bog versus ventilation). You obviously need to find something in the middle. The 5 blade Merc prop mentioned in the other post has a good reputation as a ski prop, as does the Land and Sea shiftable prop. For best skiing, you are going to have to compromise since the best ski prop will never be your best top end prop on that boat. Good luck!

Steph Adams
05-23-2001, 12:56 PM
Answers to your questions:

I am in N. California by Santa Rosa.

Everything is power, Lift, Trim and Steering. I have tried all positions and several props in between what I called out in my notes. I already have the boat sitting in Lavey's shop and they are trying to figure it out and have been for the last few weeks. I am not sure of the brand of motor mount/extension but I know the prop shaft is deep when sucked in and down.

Now Merc is talking about trying an in/out prop with big vents (1 1/8")....

Dewey
05-28-2001, 01:06 PM
Steph,
I have a Lavey myself, but fortunately I am not experiencing what you are. At least not to the same extent.

I have heard that a Mercury Bravo prop with 1" to 1 1/4" ventilation holes works really good on heavy boats with outboards. I know of a 28 foot ski racer and a 26 foot open bow cat that are running 3.0s with that prop and they say they are great. It may be worth a try.

You could try talking to Todd Smith at San Diego Eliminator (619)596-2628. He might be able to help you out.

Bill

sosmerc
05-28-2001, 02:23 PM
Might be helpful to know exactly what model 3.0 Litre you have. I have a customer with a 3.0 litre 250 hp. EFI EXLPTO. He as a jack plate also. His rig is a fairly heavy 20ft. Boston Whaler Outrage. We tried numerous props and found a 25 Inch HighFive to give the best all around performance. I was never very impressed with the bottom end on these engines. But they do deliver good mid-range and top end...and it runs dependably. I'm curious how deep you may be sitting in the water at rest? Excessive exhaust back pressure may be making it difficult for the engine to accelerate. Has this engine been modified at all? Most mods typically hurt the bottom end. A torque shifting prop may be the only way to get the best all around performance you are seeking.

D rocket
05-29-2001, 11:26 PM
This is a common problem with the 3.o l motors There are 12 holes that need to be drilled in the TUNER or BUCKET of this motor to get it to preform properly . The main problem is reaching 4000RPM's then having the prop bite. The first two holes are drilled just below the power head as idle releif. The next two just above the water line to help drain water and as exaust releif. the other 8 holes are drilled in the botom of the bucket and corosponding holes in the outer driveshaft housing as exaust releif for top end . We usualy see a 3-4 MPH improvement as well as better holeshot. Moving the rev limiter also alowes us to use the same prop and gain even better hole shot. Thanks DeWitt

alan knight
05-30-2001, 07:21 AM
did you by chance obtain a 3.0 liter with the 1.62 gear ratio? If so, this makes for a totally different game on the heavy boat such as the Sebering. Remember the 1.62 gear ratio killed the OMC V8 out of the hole. A boat will finally break loose and cavitate if it struggles long enough to get on plane with too much pitch or gear ratio,same bottom line. Might try a very low pitch wheel just for a look see.

05-30-2001, 04:57 PM
I have the 1.62 gear ratio Alpha drive (same bottom end as the big O/B Mercs) on my I/O Checkmate, 4.3 litre V6. I've found a High-5 21 pitch works excellent for hole shot. My 23" Laser II is a DOG out of the hole, can barely get on plane with a full load. With light loads and cold temps the 23" Laser II is great for top speed and is fair out of the hole. Been wanting to try a torque shift prop to see how much I can improve hole-shot, without losing too much on the top.

Techno
05-30-2001, 06:32 PM
JW if you keep the prop totaly submerged a torque shift will give you an 11" launch up to 26". How would your boat come out of the hole with an 11" prop? You definately don't need the 14"-32". They do have a list of requirements for the prop to work well on each boat. Speed HP RPMs stuff like that.
Some people call them grenades others could never get them to work (tuned). They're easy to set up and won't fly apart if you don't ask them to do what they weren't designed to do. They are extremely cheap if you can find one used. Just buy the tuning kit from L&S. In fact if you post that you want one someone might have one. Chick with L&S first to see if your boat meets the requirements.

LaveyT
05-30-2001, 09:45 PM
I have heard that the big Mercs with the 1.62 are having some problems getting on plane,Barney is having the same problem.I dont think the boat is the problem,the original owner of my Lavey got it humming good in the 1/4 mile.With a 26 Raker on mine (225H.O.)It comes out of the hole as fast as the 280+ Merc did.I have pulled up a 200 pounder on two skis with three pepole in the boat with a 28 Raker.Its gotta be the gear ratio,How fast will it run??If it wont go any faster than 80 or so you could do that with a stock lowerunit and 1.86 or whatever they are.Plenty of pitch is advalible.Im begining to think my 20.2 Lavey Johnyrude combo is one of the best running Laveys around with my limited H.P.Man what a trip if I could get 86MPH on 86 octane.That would be impressive for this Pig!Good luck,and keep us posted!