Won't plane -- Hi Performance Boats Inc.

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Date Posted: 09:04:09 09/18/02 Wed
Author: vic
Subject:

Won't plane

I have a 1996 Bayliner Jazz with a 120 mercury sport jet. The motor runs smooth but the boat won't plane with two people in it unless you put one in the very front. I had Bayliner put a new impeller and sleeve in it but it still won't plane any better. Any ideas?

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Re: Won't plane -- Lance, 20:48:20 11/11/02 Mon

>I have a 1996 Bayliner Jazz with a 120 mercury sport
>jet. The motor runs smooth but the boat won't plane
>with two people in it unless you put one in the very
>front. I had Bayliner put a new impeller and sleeve in
>it but it still won't plane any better. Any ideas?

We just got a 1993 Jazz with a 90 sportjet and it seems to get up fine. The previous owner had put on spring loaded trim tabs and said that they helped a lot. Maybe they would help too. Bear in mind if you are not used to a V-hull that it won't feel like it is out of the water as much as a flatter bottom boat like a runabout. I am assuming that since Bayliner worked on it that it is in good tune?

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[> [> Re: Won't plane -- jacob harness, 02:47:40 12/17/02 Tue

overtons sells electric trim tabs that are for short transum boats.

i put some on my previous boat( a 94 jazz 90hp) and it smoothed out the entire ride with no more porposing out of the water, and planed very quickly without someone going to the front.

they cost me about $500 and i installed them in about 2 hours. i plan to put them on my 97 jazz with the 175hp jetdrive. they are more than worth the cost if you use your boat alot(or a little if you must have the best performing ride you can get).

Be sure if you order them that you are receiving the ones for a shorter transom.

need more info email me at jacobharness@aol.com

do you have info on performance parts? email me then too.

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[> [> [> Re: Won't plane -- JC, 18:51:34 06/28/06 Wed

>overtons sells electric trim tabs that are for short
>transum boats.
>
>i put some on my previous boat( a 94 jazz 90hp) and it
>smoothed out the entire ride with no more porposing
>out of the water, and planed very quickly without
>someone going to the front.
>
>they cost me about $500 and i installed them in about
>2 hours. i plan to put them on my 97 jazz with the
>175hp jetdrive. they are more than worth the cost if
>you use your boat alot(or a little if you must have
>the best performing ride you can get).
>
> Be sure if you order them that you are receiving the
>ones for a shorter transom.
>
>need more info email me at jacobharness@aol.com
>
>do you have info on performance parts? email me then
>too.
Hello, have a 95 Jazz 120 and the previous owner used to ride alone and the fix to this was 3-5 gal. jugs filled with water stored in the front compartment. I took them out because I always have company who sit in the front seats anyway, but give it a try, may work and cheap fix if it does.

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[> Re: Won't plane -- Martin, 21:53:32 11/20/02 Wed

>I have a 1996 Bayliner Jazz with a 120 mercury sport
>jet. The motor runs smooth but the boat won't plane
>with two people in it unless you put one in the very
>front. I had Bayliner put a new impeller and sleeve in
>it but it still won't plane any better. Any ideas?

Exhaust gas leaking from the bottom of the boat can get sucked into the jet pump and cause it to cavitate. Check the screws holding the ride plate on and the gasket around the edge of this plate. The ride plate is the big black aluminim plate on the bottom of the boat. Exhaust gas can leak from the gasket around the outer edge of the plate or from the edge of the "window" in the middle of the plate where your intake grate is mounted. You can try some silicone sealer on these areas if you suspect leakage. It won't last for long, but will tell you if this is your problem.

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[> [> Re: Won't plane -- Phil, 12:39:01 03/11/03 Tue

>>I have a 1996 Bayliner Jazz with a 120 mercury sport
>>jet. The motor runs smooth but the boat won't plane
>>with two people in it unless you put one in the very
>>front. I had Bayliner put a new impeller and sleeve in
>>it but it still won't plane any better. Any ideas?
>
>Exhaust gas leaking from the bottom of the boat can
>get sucked into the jet pump and cause it to cavitate.
>Check the screws holding the ride plate on and the
>gasket around the edge of this plate. The ride plate
>is the big black aluminim plate on the bottom of the
>boat. Exhaust gas can leak from the gasket around the
>outer edge of the plate or from the edge of the
>"window" in the middle of the plate where your intake
>grate is mounted. You can try some silicone sealer on
>these areas if you suspect leakage. It won't last for
>long, but will tell you if this is your problem.

I have no answers for your problem, but rather I have the same problem with my 1993 bayliner jazz (90HP). I think it just isn't pumping enough water to develop the thrust needed to perform like it is supposed to. It will get on plane with just one person on board, but the second person has to sit up front to get on plane. She'll only run about 31 mph with just one person.

I just had the engine checked out - good compression, good spark, and they cleaned the carbs. There is no tach so I'm not sure how fast the engine is turning. Anyway, I performed a visual inspection on the jet pump impeller and wear ring and they have a very close tolerance (less than 1/16 inch - I recently replaced a wear ring on one of my jetskis, and there was about a 1/4 inch gap between the impeller and wear ring and it made a huge difference in performance). So now I'm at the end of my rope.

Any ideas would be appreciated.

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[> [> [> Re: Won't plane -- Norway JAzz, 00:29:40 06/30/04 Wed

I have a Jazz from 1996 with 120 HP. I have the same problem that it takes a lot of time to plane. Sometimes when I give full gass to the engine it goes in plane with 2 persons. Normally I have to but the second person in front for a while. Have you other guys solved the problem? Please reply.. I am living in Norway and I think there might be 8.or 10 boats like this all over Norway so it would be very find to have som international help.

Thank you !

>>>I have a 1996 Bayliner Jazz with a 120 mercury sport
>>>jet. The motor runs smooth but the boat won't plane
>>>with two people in it unless you put one in the very
>>>front. I had Bayliner put a new impeller and sleeve
>in
>>>it but it still won't plane any better. Any ideas?
>>
>>Exhaust gas leaking from the bottom of the boat can
>>get sucked into the jet pump and cause it to cavitate.
>>Check the screws holding the ride plate on and the
>>gasket around the edge of this plate. The ride plate
>>is the big black aluminim plate on the bottom of the
>>boat. Exhaust gas can leak from the gasket around the
>>outer edge of the plate or from the edge of the
>>"window" in the middle of the plate where your intake
>>grate is mounted. You can try some silicone sealer on
>>these areas if you suspect leakage. It won't last for
>>long, but will tell you if this is your problem.
>
>I have no answers for your problem, but rather I have
>the same problem with my 1993 bayliner jazz (90HP). I
>think it just isn't pumping enough water to develop
>the thrust needed to perform like it is supposed to.
>It will get on plane with just one person on board,
>but the second person has to sit up front to get on
>plane. She'll only run about 31 mph with just one
>person.
>
>I just had the engine checked out - good compression,
>good spark, and they cleaned the carbs. There is no
>tach so I'm not sure how fast the engine is turning.
>Anyway, I performed a visual inspection on the jet
>pump impeller and wear ring and they have a very close
>tolerance (less than 1/16 inch - I recently replaced a
>wear ring on one of my jetskis, and there was about a
>1/4 inch gap between the impeller and wear ring and it
>made a huge difference in performance). So now I'm at
>the end of my rope.
>
>Any ideas would be appreciated.

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[> [> Re: Won't plane -- vic, 11:04:25 07/07/03 Mon

My rpm is at 5200 max and I can get about 45 mph with two people once it planes. The third person in it takes several min to reach plane and forget plane on the fourth person. But I did notice the plate seemed to be warped to one side and was missing a screw so I'm going to try the gasket before buying aftedrt market, thanks!

VIC

>>I have a 1996 Bayliner Jazz with a 120 mercury sport
>>jet. The motor runs smooth but the boat won't plane
>>with two people in it unless you put one in the very
>>front. I had Bayliner put a new impeller and sleeve in
>>it but it still won't plane any better. Any ideas?
>
>Exhaust gas leaking from the bottom of the boat can
>get sucked into the jet pump and cause it to cavitate.
>Check the screws holding the ride plate on and the
>gasket around the edge of this plate. The ride plate
>is the big black aluminim plate on the bottom of the
>boat. Exhaust gas can leak from the gasket around the
>outer edge of the plate or from the edge of the
>"window" in the middle of the plate where your intake
>grate is mounted. You can try some silicone sealer on
>these areas if you suspect leakage. It won't last for
>long, but will tell you if this is your problem.

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[> [> Re: Won't plane -- tom, 08:56:24 08/24/03 Sun

>>I have a 1996 Bayliner Jazz with a 120 mercury sport
>>jet. The motor runs smooth but the boat won't plane
>>with two people in it unless you put one in the very
>>front. I had Bayliner put a new impeller and sleeve in
>>it but it still won't plane any better. Any ideas?
>
>Exhaust gas leaking from the bottom of the boat can
>get sucked into the jet pump and cause it to cavitate.
>Check the screws holding the ride plate on and the
>gasket around the edge of this plate. The ride plate
>is the big black aluminim plate on the bottom of the
>boat. Exhaust gas can leak from the gasket around the
>outer edge of the plate or from the edge of the
>"window" in the middle of the plate where your intake
>grate is mounted. You can try some silicone sealer on
>these areas if you suspect leakage. It won't last for
>long, but will tell you if this is your problem.
I am having the same problem on a 96 sea rayder with a 120 sportjet. i am interested if the gasket fixed the problem because i recently had the intake grate replaced. the boat is new too me so i dont know if the problem was there before the grate was replaced. my rpms are about 5500 and one person has to go to the front and forget about a third in the boat.

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[> Re: Won't plane -- Jo Jennings, 16:19:19 01/19/04 Mon

>I have a 1996 Bayliner Jazz with a 120 mercury sport
>jet. The motor runs smooth but the boat won't plane
>with two people in it unless you put one in the very
>front. I had Bayliner put a new impeller and sleeve in
>it but it still won't plane any better. Any ideas?

This is a little late for last year but in the several years I've owned my Jazz the lack of planeing (sp) is only when I have seaweed up in the intake. I've had it professionally cleaned twice and several times just got into the water and stuck my arm in a cleaned it out. Occasionally running in reverse (for only a second) helps. I try to coast thru any goop I see showing up which is not too often since we boat on the 90 miles of Lake Roosevelt in WA st. Hope this is your only problem. I've had 4 people in the boat and still no problem getting up on plane. Takes longer but...
Jo

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