94 Regal Rush 14" jet boat w/Merc Sport Jet 90

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Dfelix20

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Engine starts fine, idles fine and gets up to 4.5-5k rpm at full throttle, but I am not moving the speedometer. looking off the back, the amount of wake and water being moved you would think I was moving 30-35 like the boat used to run. I jumped a wake one day and suddenly lost thrust. Pulled the prop and wear ring, wear ring was pretty bad on one end, but in spec the other 2/3rds. Went ahead and replaced it, threaded prop is $500ish and doesn't look bad, ground the front and rear edges smooth to prevent cavitation, can barely get a .01 feeler between the blades and wear ring.

I have a video looking off the back at full throttle, but not sure how to post it. Hoping someone can get me in the right direction.
 

Piratehooker

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

Not sure what direction you are looking to go? Are you saying your speedo doesnt work?
 

Dfelix20

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

The speedo works, I am unable to go fast enough to register on it.
 

renrab

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

What shape is the ride gasket in?

I just bought a 1994 Dynasty Jet Storm w/ SportJet 90.

First thing I did was changed the ride plate gasket, Night and day difference for 45$.
 

Dfelix20

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

The gasket is in great shape and tight. It ran awesome for 3 weeks, hitting 35mph in seconds, until that last wake jump, now it won't go fast enough to move the speedo needle
 

Dfelix20

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

Video at full throttle, moving less than 10mph

http://www.youtube.com/watch?v=IAgfm8_lGw4&feature=youtu.be
 
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Dfelix20

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

Yes, all bolts and screws are tight and gate is fully clear of the jet drive.
 

Ohio79

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

Any chance your carbs are dirty or have a fuel/air issue
 

Dfelix20

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

The motor seems to run the same as before the loss of thrust. I have ordered a new ride plate gasket, if that does not resolve it, I am going to get a meter to test my rpms on the water and start checking for power issues.
 

dsrace

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

if it won't run over 10 mph then you wouldn't be able to even plane out, does it plane out?
 

Zydecobon

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

I have a 95 model 120 hp 14' rush that had the same issue for several years. Although it would work intermittently. Loss of power, would only run at 10 mph. Changed wear ring, adjusted ride plate, changed plugs, replaced fuel lines, rebuilt carbs, new lanyard switch.....nothing fixed it permanently....it kept coming back. Replaced rev limiter at about $45.00. Runs like a scalded dog! The rev limiter protects the engine from damage when it comes out of the water. Mine had shut down the fuel and power. Sometimes it kicked in and would not kick out of service. It finally shut the boat down permanently. It would turn over but not start. Pretty cheap fix for my boat.
 

laurencen

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Re: 94 Regal Rush 14" jet boat w/Merc Sport Jet 90

I have a bayliner Jazz that is having the same issues, put on new impeller and wear ring, motor is getting to top RPM however prety hard starting, needs a bit of gas in the intake but its like its tied to the dock, on mine the ride plate was straightened by the previous owner I am going to look at possible exhaust leak causing cavitition in the intake, does this sound like a place to look or am I grasping at straws
 

Dfelix20

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Replaced wear ring, had impeller serviced, replaced ride plate gasket, replaced stator, carbs serviced, took to a jet boat shop (options limited when its not a Seadoo jet) they wanted to pull engine and cjeck jet drive lower unit, and way too much money....still not able to get enough speed to get up on plane .... any new ideas or experience to share before I pull the engine and dig in?
 

dsrace

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don't know if it is the same issue but i had similar issues with mine. i checked everything and it all was in good running shape but nothing fixed it. i have no tach but big wake and sounded rapped up on rpm. it wouldn't plane out and i noticed that if i turned hard left the third cyl would kick in and out for a sec but not every time. so i started checking fuel delivery. mud wasps had made a next in my fuel vent and there was some gunk in my fuel tank partially clogging the pick up screen. i hooked a hose to the fuel take with a transfer pump , dill operated, i bought at menards for $10 and some clear vinyl hose so i could see what was coming out. i started to suck fuel out of the tank out of from the fitting the fuel line hooks too and my check valve is removed from the pick up line btw. fuel would come half way to the pump and then suck itself back into the tank . this happened 5 times so i put a gallon of fresh fuel in the gas can and forced it into the tank then sucked 2gals back out. it started transferring freely after that. i did this 12 times until no blockage. ran better than ever after this so now i need to pull the motor this winter to pull the tank to clean it right. it always started but started a little hard so i put a primer bulb on it. it always ran , sometimes it would plane out right off idle but then wouldn't do it the following summer and no matter wouldn't get over 15 mph if that. so i would check your tank vent and make sure it can get all the fuel it needs at wot. mine passed enough for idle but not the additional for wot.
 

Mmccoytrm

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May 17, 2020
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I have the same issue in my 94 rush, did you buy a fuel pump rebuild kit?where from? I cleaned the gunk from the pump...not sure if it'll work...plz lmk
 
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