Power Issue?

Hey guys, I have a 00 Mob V with approx. 2000 lbs of ballast. I have the upgraded prop with the 5.7L Assault V8 and it will not get on plane fully loaded. Actually, last weeekend, with 10 people in the boat and no ballast filled, it struggled and took over a minute to pull one light person out of the water & to plane. I've seen some posts on here with 3k of ballast and pulling up on plane in nothing flat, what's wrong with mine? Any ideas? Also go through about 25 gallons of gas in a full day, maybe day & a half; normal or related? Let me know you're ideas, thanks.

Your boat should plane without much of an issue, especially if you have a lower pitch prop. Is it carb or EFI? There could be a number of reasons it's down on power, but it definitely sounds like it is.

It is an EFI, yeah I would think there should be no problem pulling someone with a full boat or even full ballast. It will run near full throttle and never plane out with the ballast all full.

prop=key to the whole thing it sounds like. Are you sure its a wakeboard upgrade prop? Only reason im questioning it is I had a 03 lsv with the standard prop and it would not get my boat on plane with 2k in surf balast where my newer 08 lsv (same 325hp in both boats) with the "wakeboard" prop will plane the heavier boat with 2k surf balast and with people in it no problem.

Here is a pick of it, I was told it was the upgraded prop when I bought the boat and assumed so since it is a 4 blade. Not sure you can tell by the pic or not, let me know. Thanks.

from the pic i would say its not-only cause it doesnt look like my prop-could be very wrong tho. look for some numbers stamped in the prop and that should say what size it is. 13x13,14x17 or something like that.

Just because it has 4 blades doesn't mean it is designed for heavily weighted boats. My 2001 Outback DD came with a 13x13 3 blade and when I damaged it, I swapped it to a 4 blade, but still a 13x13.

True, i took a quick glance over lunch and did not see the size posted anywhere just a 14 off by itself then it looked like a 1 and an 8 spaced pretty far apart from each other and "cup" stamped on it. I'll look again today after work.

Both my boats had 4 blade props--world of difference in them. Kinda think you have the standard prop.

My 2002 lsv came with a 4 blade 14 x 18 1/2 prop. it does ok with 1500 pounds ballast but I would still like to get a lower pitch prop.

prop dia, pitch, cup & shaft dia are stamped in the face and should be visable looking at the prop from the back of the boat. should be 14.25 x 14 , .90, 1&1/8 for the wakeboaed prop.

Another place to look to see if your losing power or not that has nothing to do with your prop is engine compression.

Do a cylinder compression test to see if the engine is getting tired or not. You can by the compression gauge at the local car parts store for 20ish bucks.

Pull all the plugs out.
Disconnect the ignition system
Hold the throttle wide open and crank the engine about 4 revolutions.
You should see a number between 150 and 250psi
Now do this to all the cylinders and they all should be within 10-15% of each other.

This helps tell you if you have a bad cylinder making less power then it should. From there you can farther tell if its the heads or piston rings causing problems.

The prop is the first place to check i agree, but this is how you test your engine to make sure its in good condition also. When you have 10 people in the boat the prop makes no difference if your only making 150hp in a 300hp engine.

Well, just got home and crawled under there to get a better look. It is a 14x18 1 1/8" 4 blade prop. Is this what is causing my performance issues? Like I said, it will not pull up on plane with the ballast full. I would think the compression is fine as it runs smooth and never missed a beat, just struggling to get on plane when it's under a heavy load. How much will the 14.25 x 14 prop help? Thanks.

14x18--isnt that more of a top end/speed prop ?

not sure if it is or not, i know last time i was cruising, full tank of gas and only 2 people topped out right around 37 or so.

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Originally Posted by dereklschmidt

not sure if it is or not, i know last time i was cruising, full tank of gas and only 2 people topped out right around 37 or so.

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What was your RPM's at that time?

How long have you had this boat? Has it had this problem since you have owned it?

Not sure exactly what my rpms were at, I would say right around 4500 prob.

I bought the boat back in April and the performance has not changed any that I have noticed. I just recently started weighting it down more for a bigger wake.

going from 13.5 x 17.5 to 14.25 x 14 made a huge difference on my 05 lsv. you def need to reprop.

I may have to try that, I can not find that size from Acme is OJ the only one that has it? Also, I would want the .90 cup, correct? Basically the part # & description below?

PART #466
14.25 X 14 LC 1 1/8" 4-BLADE .090 CUP

Acme 1235 - 14.5 x 14.25 - .105 cup. I have the OJ 466. Both are good props. You can get 10% off at Skidim. Look on their home page for the codes.

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Originally Posted by VA LSV

going from 13.5 x 17.5 to 14.25 x 14 made a huge difference on my 05 lsv. you def need to reprop.

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I have the 13.5 x 17.5 4 blade prop and with 10 passengers i have never had a problem planing the boat.??? so the 14.25x14 would give better hole shot and lower top end speed??:confused:

much better hole shot and you will loose a little top end. also holds speed much better when loaded. it wasn't that mine wouldn't plane out when loaded, it just took while and i was on the throttle hard getting a rider up. after changing props, it gets on plane and i back off the throttle very quickly. should save on gas if you board with ballast.

Yeah, mine will plane out pulling a rider up with 10 passengers on board, but it is slow and does not like sharp turns. However, if I fill up my ballast, approx 2200 lbs total, with 4 people in the boat it will not get on plane whether I'm pulling a rider or not.

I use a lot of gas when I'm surfing as well, the lower pitch prop should help with that too right?

VA lsv, What was your top end speed with the old prop and now with the new prop. mine will do 47 two passengers no ballast with the 13.5 x 17.5 I need high end speed to ski and barefoot as well.

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Originally Posted by dereklschmidt

I use a lot of gas when I'm surfing as well, the lower pitch prop should help with that too right?

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Yes it should

A prop upgrade is definitely called for. An 18" pitch is not an "upgrade" prop for heavy ballast.

However, there may be more going on here. Even under load, 20-30 MPH is in the usual operational range for either prop. It's just that a lower-pitch prop should get you there quicker and with less engine strain while accelerating (at the expense of a bit of top speed). Plus, you'll have the engine nearer its more efficient mid-range when surfing.

If your engine is putting out anywhere near its 300 HP, you should get up to speed. Derek, your original post said that it took a long time to get a rider out of the water with 10 people (and no ballast), and really talks only about planing... but what about the actual speed? Did it get up to the usual riding speed? If so, and you were not planing, replacing the prop (and possibly doing some engine maintenance) is not going to get you on plane, since planing at a given speed would be a function of the hull and the weight that it's carrying.

If your boat is just digging a trench in the lake... well isn't that the effect that we want for wakeboarding and wakesurfing? Yes, it takes more fuel, which is the price of creating a big wake. When explaining to newbies what a wakeboarding boat is, I often tell them that the point, unlike a runabout or a ski boat, is to NOT get fully on plane in the speed range for towing a rider.

I use the term "planing" a bit vaguely. With the ballast all the way full, I can not get to wakeboarding speed, just seems like it pushes and pushes never getting much over 16 mph.

With the 10 people in the boat, no ballast, I can get to speed, just takes a lot longer than it should, imo. Once I got to speed, roughly 19mph for that rider, it planned out, however, perfect pass had a hard time holding it at 19 so I increased speed to about 20.5 to get it to hold a more consistant speed. This, from what I understand, will be fixed with a new prop as well.

I never have a problem with getting up or anything under small loads, I usually ride with the wake plate at about 15%, mid sack 1/2 full, front sac 1/4 full, and rear sacks about 1/3 full with just a driver at 22 mph and it does fine, I expected getting up faster, but still does the trick.

Do you have all these problems when not using PP. maybe something is not set up right.

yeah, all problems are consistant, whether it be PP or w/o PP.

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Originally Posted by dereklschmidt

I use the term "planing" a bit vaguely. With the ballast all the way full, I can not get to wakeboarding speed, just seems like it pushes and pushes never getting much over 16 mph.

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That clears things up.

Changing the prop will adjust the torque. Compared to a car, a regular prop is like being in 3rd gear all the time, and a high-pitch prop will feel like being in 2nd gear all the time. Another name for a transmission is a "torque converter", because it converts the engine's most useful RPM range to a useful vehicle speed range.

However, your boat appears to also have a problem with power (power is the rate of energy transfer, which is always at WOT -- wide open throttle). If your engine were really putting out anywhere near 300 HP you would be able to do at least 30 MPH even with the added weight.

I'm jumping in kinda late here but I have to agree, there might be more going on than just your prop. By the way call OJ or Acme, give them your details and they'll tell you the right prop, eliminating a lot of quess work.

How many hours on the boat? How tight is the engine. We are talking a 10 yr old boat here. If it has been run hard and only minimal maintanence she could just be tired. I can run 1400 lbs of ballast and barely feel it. While my boat is much smaller, these motors have amazing torque.

Sounds like I need to run a compression test. Like I said, I've only had the boat about 4 months now, I was told all maitenance was done and it was in meticulous condition. However, when we took it out, the ballast had a leak and we could not fill them up to test a full load. I talked to the mechanic that did all work on this boat for the last 3 months, who did a compression test, and said everything checked out. I do not remember the exact numbers now.

There is approx. 860 hours on the boat. I even talked to Indmar prior to purchasing the boat and they said the engine should be fine up to around the 1400 hr mark and even then may just need to change rings.

Just seems to me, that if the engine is getting tired, i would be able to tell from the sound or all around performance, not just at heavy loads. I could be very wrong though.

No, as an engine starts to get tired it will still perform and sound as normal, it's just when you try to push it that it does not perform up to par.

Not too good of news, lol. Any suggestions on what else I need to check beside compression? Thanks.

On a boat not realy. Its hard to realy test the engine in a boat like a car. The best way to realy know what your engine is doing is a compression test, air flow test, and dyno test. On a boat the only test you can do with out taking the engine out is the compression test.

The engine will sound normal unless a rod, bearing, or valve is going out. It jsut wont make the power you need. Another way to test is a fuel flow test to see how much fuel it burns completly. This isnt the best way to test it, its just another way.

I will be more then happy if i can get 900 hours out of my engine. Thats close to 10 years of service and most car engines dont last that long and we dont run those engines anyware near as hard as a boat engine.

Well, did some checking on my boat this weekend. Compression checked out good, fuel filter was pretty dirty and spark plugs are a little weak. Gonna replace the fuel filter & spark plugs and get back out there. Sure those two things had a little to do with it feeling sluggish.

Keep us posted. Did you check your cap and rotor? There could be some real corrosion in there.

Yeah, cap, rotor & wires all look good. Gonna take it out this weekend.

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Originally Posted by OldeBoy

Keep us posted. Did you check your cap and rotor? There could be some real corrosion in there.

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Yeah I would think that if you had weak spark, changing these items would almost be a given.

Just an update, took her out yesterday and it ran like new. Had no problem getting anyone out of the water, even with the plate up and ballast almost full.

Thanks for all of your help guys. Unfortunately, due to financial reasons, I'm going to have to sell. I REALLY REALLY don't want to, but it's looking like I may need to. I'll be using it till it's sold though! Posting it in the classifieds now. Thanks again.