Mercury Marine Sport Jet 90 VERY SLOW

[AlejandroD1]

Hello,

I am new to this forum, My name is Alex, so hello to all!, I havea problem with a boat since I buy it used. The problem is that this boat is very very slow. They check the engine and the jet pump and they are fine. But the boat is still slow, one mechanic suggest that the pump has the wrong angle. mmm What do you think?

Thanks for your comments

 

[kend301]

Re: Mercury Marine Sport Jet 90 VERY SLOW

Alex , welcome to Iboats , first of all what kind of boat do you have they put this engine in several models . Also define slow , these boats take forever to plane and will do 32-36 mph with one person and 1/2 tank of fuel .
What you want to check is move the throttle to wide open (with boat OFF ) and look at the gate on the back of the boat , it should be above the jet nozzle by about 1/8 to 1/4" . A set of smart tabs is a very good investment for these boats , you will plane very quickly and have much better acceleration .

 

[AlejandroD1]

Re: Mercury Marine Sport Jet 90 VERY SLOW

Thank you very much for you answer, my boat its a Sea Pro Jet boat 96, the problem is that the boat never planes, I send the boat to a shop and they told me that the engine is fine, they check the rings in the pump and they are ok to.

 

[dmball]

Re: Mercury Marine Sport Jet 90 VERY SLOW

I just got my 94 Regal rush-(sport jet 90) going today. Had 2 guys(about 350lbs) in it with a full tank. Hit 38 on calm water. My speedo is pretty dam close with the gps too.
Also unless if I have four passengers it take about 3-5 seconds to get it to plane. With four passengers it only take maybe 2 more seconds.
I have had no performance issues yet except loosing all spark. So Im not sure what it could be. But it sounds like somethings going on. Good luck!

 

[JW-JetBoat]

Re: Mercury Marine Sport Jet 90 VERY SLOW

Is your intake grate (where the water is sucked in) loose? Take a look below. My Northstar's screws were lose on it and just by being slightly loose it affects the power very drastically.

 

[AlejandroD1]

Re: Mercury Marine Sport Jet 90 VERY SLOW

Is your intake grate (where the water is sucked in) loose? Take a look below. My Northstar's screws were lose on it and just by being slightly loose it affects the power very drastically.

I review the intake and the screws are not loose. The problem is that the boat never planes.

 

[kend301]

Re: Mercury Marine Sport Jet 90 VERY SLOW

Do you know how fast you are going ? what does the speedo say and have you gotten a gps speed reading ?