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milehighbu

Significant Engine HP loss. Help!

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milehighbu

Gentlemen,

I recently purchased a 2012 MXZ with the 6.0L (410HP) Indmar engine with 420 hrs on it. I do live in Denver which is 5280 feet in elevation but I have the Malibu recommended 15x12 high altitude prop (brand new). The problem is with only 3 people and no ballast with the wedge down the boat will not plane out at all. It simply can't overcome the wedge which makes the wedge a completely useless feature. Again, all ballast tanks are empty. Any ballast added just makes it worse. In comparison, my friends 23 foot 2004 VLX with only a 350 has no problem planing out with his wedge down and all 4 ballast tanks filled so the altitude excuse doesn't hold water. The boat recently has seen multiple error codes suggesting bad O2 sensors but my local Malibu dealer has cleaned the sensors and moved them around and has ensured me that they are not the problem. My dealer and Indmar have suggested low grade fuel was causing carbon buildup which is what was causing the O2 sensor code. Today, the dealer siphoned the low octane gas out and put high grade gas in and we did a lake test today and was error code free (first time ever). This is good, however, the boat still simply does not have near enough power to overcome the wedge with only myself and the 2 dealer mechanics in the boat with no ballast. Even the dealer mechanics agreed that the boat felt light on HP.

My question is what could be wrong with the boat or what could possibly happening that is dropping the performance of the boat with the wedge down? I would expect pretty good performance from a 6.0L 410HP motor; even at altitude with a high altitude prop. Could it need new spark plugs, clogged injectors, something else....????? The mechanics suggested a bottle of octane booster but quite honestly I highly doubt that will wake it up enough to perform the way I would expect this boat to run.

The only good thing is Malibu gave me a 6 month warranty on the boat since this is pro rider Phil Soven's former sponsorship boat.

So far I am regretting my purchase of a Malibu over other brands as I have had this boat back to the dealer 6 times since I bought it which is once for every time I have used it. This would be a great boat if I could just get all the bugs worked out of it.

Thanks for the suggestions everyone.

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oldjeep

Have they done a compression check?

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milehighbu

No compression tests as of yet. My dealer told me they plan to call indmar and ask. One thing I neglected to mention is this boat did overcome the wedge with full ballast the very first time I used it but only once. Never again has it been able to plane out. Would a bad temp sensor or fuel pressure regulator cause such a decline in performance?

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JeffK

Have you tried getting the center and front tanks full and see if that helps at all?

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Sixball

Cleaned the O2 sensors? Replace them. Might have the cat's plugged up.

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milehighbu

The dealer cleaned the O2 sensors once already but at Lake Powell we got the same error codes as before. I don't think they have cleaned the O2 sensors yet but I will ask them to. How can the temp sensor be tested? Any other thoughts?

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Matty_gs

I don't have any suggestions, but I almost purchased a 22mxz that was formerly owned by Phil (yellow and black). Before driving up to Michigan, I had them perform a compression test and it came back terrible.

I hope that's not the case here, but I won't look at any boats owned by pro riders from here on out.

Did it run well before? Did you test drive the boat?

Edited by Matty_gs

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JasonK

If it's low on power it would be felt with or without ballast, no?

What's the top speed without the wedge?

How's the holeshot without wedge or ballast?

What kind of wedge? or is there only one kind now?

If I ballast my tiny ski boat for surfing, I can't plane either. And i have no wedge.

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Ndawg12

If it's low on power it would be felt with or without ballast, no?

What's the top speed without the wedge?

How's the holeshot without wedge or ballast?

What kind of wedge? or is there only one kind now?

If I ballast my tiny ski boat for surfing, I can't plane either. And i have no wedge.

:plus1: How about a WOT run with no ballast noting top speed and rpm

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milehighbu

WOT speed is 39MPH with no wedge or ballast. This is at my altitude with a 15x12 prop which is the recommended prop from Malibu at my altitude. These boats are not built for top speed though. What good is the wedge if I can't plane out with it down, no ballast and only 3 people in the boat? The dealer mechanics suggest that this is just how this boat performs. Im not buying that. If that is truly the case then I will be getting rid of the Malibu and going with another brand.

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oldjeep

Once again - compression check. Without checking the basics there is no reason to be looking at anything else.

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Ndawg12

39 sounds right for a 15" prop. Time for a compression test.

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SmoothWaterMan

Start with the basics, as everyone has stated.

- Power balance test, see if any dead cylinders. Boats today will run on 6 cylinders almost as well as 8, and just be a little sluggish until asked to work, then they have low power.

- If all cylinders are firing and show an rpm drop during the power balance test, do a compression check, or better yet a cylinder compression leak down test.

Those two tests will give you a baseline.

- Engine needs to be able to turn 4800-5200 rpm at WOT, in the water, with or without ballast on board. Engine and prop combination need to be matched to allow this. 39 mph is fine, if the rpm is in the factory spec range.

- Verify that the wedge is actually moving to full _down_ position, and not at _max_wedge_downforce_ position. Most all boats will not plane with the wedge at max_downforce, which is only partially down.

Peter

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RTS

If that is truly the case then I will be getting rid of the Malibu and going with another brand.

Doubt this is a 'brand' issue. But more of a previous owner ('pro rider' or otherwise) riding a boat hard and putting it up wet, so to speak, and then pawning it off on someone else.

Be thankful for your 6 month warranty.

But I would reserve bashing the 'brand' until you figure out what is wrong....and there is something wrong.

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SmoothWaterMan

Just as FYI, we had a case yesterday where a customer with a LS1 in a ski boat felt that the engine was just sluggish as compared to normal, but not horrible. Just was a little slow pulling skiers up and didn't accelerate quite as fast as normal. Customer expressed thoughts of fuel filter clogged, etc. Sounded like more of a nuisance than an issue.

Tested the boat and it only turned 4000 rpm at WOT.

Turns out the engine had two cylinders down and out on the right bank. But, it ran great for a 6-cylinder LS1. Adjusted the oil level, changed the spark plugs and suddenly we've got 5000 rpm out of it and all 8 cylinders working.

Peter

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milehighbu

Oh man, thanks everyone for all of the feedback. I will definitely suggest my dealer do a compression and a leak down test to ensure that all cylinders check out ok. I want to keep the boat and don't want to appear like I am bad mouthing the Malibu brand but I can only go by my experience with the product I purchased. Boy am I glad I insisted on a 6 month warranty. The wedge on this boat has failed twice now which the dealer is hopefully fixing again.

Question: Should I expect this boat to be able to plane out regardless of what position the wedge is in? Should I expect it to plane out from wedge all the way up to all the way down and everwhere else in between? I ask because this last wedge failure we noticed the wedge appeared to be stuck at about a 45 degree angle.

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shawndoggy

Oh man, thanks everyone for all of the feedback. I will definitely suggest my dealer do a compression and a leak down test to ensure that all cylinders check out ok. I want to keep the boat and don't want to appear like I am bad mouthing the Malibu brand but I can only go by my experience with the product I purchased. Boy am I glad I insisted on a 6 month warranty. The wedge on this boat has failed twice now which the dealer is hopefully fixing again.

Question: Should I expect this boat to be able to plane out regardless of what position the wedge is in? Should I expect it to plane out from wedge all the way up to all the way down and everwhere else in between? I ask because this last wedge failure we noticed the wedge appeared to be stuck at about a 45 degree angle.

no if it's stuck there it's like dragging a parachute. And really does no good for wake/wave in that setting either (imho etc etc).

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milehighbu

If the wedge only goes 1/2 way down could that be the reason I don't plane out instead of a potential engine issue? It is that severe of a performance issue.

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shawndoggy

it won't help, that's for sure.

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iliketoski

Try the wedge first!

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JasonK

yes it's that severe of an issue and will keep you from planing.

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SmoothWaterMan

- Verify that the wedge is actually moving to full _down_ position, and not at _max_wedge_downforce_ position. Most all boats will not plane with the wedge at max_downforce, which is only partially down.

The Wedge operational range is only about 4" of travel, from the full down position (least downforce). Anything greater than this is the wedge in the transition phase, between down and storage. This is no-man's land, and it sounds like the true cause of your issues.

I don't think you have any engine issues.

Edited by SmoothWaterMan

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milehighbu

UPDATE

It turns out my boat had the wrong type of wedge controller. It had a 3 pole instead of a 5 pole controller (whatever that means). Essentially, the controller was not counting actuator revolutions correctly. Therefore when the maliview screen was reporting the wedge being all the way down it was really only 1/2 way down which makes it nearly impossible for the boat to plane out. Malibu sent a new controller and new actuators to my dealer who made the replacement repair. We lake tested the boat and now the dash reports the proper position of the wedge. Once the wedge was truly all the way down the boat planed out just fine. Thank goodness this wasn't an engine issue since that is harder to diagnose and repair. I am encouraged that we finally have shaken all the bugs out of this boat but the proof will be in how many reliable hours of use I can get. I have a weekend trip planned this weekend. I am hoping this will be the first trip I don't have to take the boat back to my dealer for repair.

Wish me luck!!

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