Sport Jet 90 Will not plane and has no speed, HELP!

[Trailratethisfx4]

Ive been working on this boat for a few months and have her runnng great. My problem is i cant get the boat to plane out or gain any kind of speed. I thought it was the ride plate seal so i replaced that this morning and took the boat out for a test just to find out it still doing the same thing. Revs up with plenty of power when i put the trottle down but like i said it wont plane out or gain any speed over 5 or 10 mph. Is there something else that could be the problem, i would hate to go out and buy a new impeller and wear ring and still have the same issue. Any thing any one can think of that might be the issue?

 

[emoney]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Could be a myriad of issues. Start with the simple stuff, like; is the shift cable operating
correctly? I've seen people have planing issues because their cable wasn't adjusted to
allow the throttle to go all the way down. Is the boat starving for fuel when you have
the throttle wide open? Check the fuel filter, and the entire system for that matter.
What happens when you push the throttle all the way forward?

If all that is ok, then it's time to check underneath and have a look at the wear ring.
The impellar, too, of course. Look for chips & dings in it.

 

[silly34]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

I suspect your impeller/wear ring. You can refinish the wear ring using JB weld and then sanding the rough spots. You want a pretty tight clearance with the impeller blade. You can also repair the impeller or replace.. a few on ebay. Also look at getting some trim tabs..love them!

http://www.nauticusinc.com/ I think iBoats sell's these.

B.

 

[silly34]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

OH yeah.. make sure your gate is clearing the jet nozzle all the way.

B.

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

The gate clears the nozzle, thats the first thing i checked. We did the JB weld trick with the wear ring also didnt work. The boat has some vibration when putting the trottle down cant figure that out either! Boat does not starve for fuel it runs great and feels like it has lots of power when putting the trottle down. It just does not plane out or gain any kind of speed.

 

[silly34]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

You aren't missing ANY screws in the ride plate correct? Could still be getting air/exhaust bubbles in with your impeller. Also you don't want to over-tighten the ride plate as this will distort the seal causing leaks.

B.

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

No screws are missing. I have no idea where air/exhaust bubbles would be comeing from. the bolts are not over tightend. im just trying to get this all figured out, i would hate to order an impeller and wear ring and still have the same problem.

 

[Part-time]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Do you have a tack in your boat? if not, use a hand held one.
If you're reaching full RPM's the problem is in your jet drive.
If it's not reaching full RPM's then it's the motor.
Don't just go by sound... it can be deceiving.

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

no theres no tack ive been trying to find one for a 3cyl but no luck. where can i get a handheld tack? never heard of one. I really feel like this boat is hitting its rpm range by how much power is at the throttle, but like you said sound can be deceiving.

 

[Anders67]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Hi.

If vibrating, look on impeller so the blades is perfekt and ok, and nothing stuck in it. It shall be very little clearence between impeller and wear ring ( like 0,10-0,15 mm.) Look on whater intake plate too so free of debris.


Also check the sealing on side of pump unit in back end of boat, both sides. There i had a leak on mine sucked exhaust-gas down making the pump cavitate/ loose the grip in whater.




If it?s the pump unit that causing the problem, you shall hear the engine hit top rpm on wot, and the rev limiter cut in .


On engine

Put it in full throttle and look on the linking on engine, do you see the linking move the trigger to increase timing?. If you look on the carbs., can you see that they are fully opened on linkage? ( see it on left side there are a line on carb throttle axel, that shall be leveled in full throttle on both carbs).

There are a thin plastic hose between carbs and air intake on left side carbs. Look so they are cleared, nothing cloggin them and open in to the carbs through the hose fittings ( just blow through them).



Fuel.

Check so free of debris in gas-hose from tank to fuel pump.

Inside lid ( one screv) on fuelpump you have one steel filter, check so clean and make shure you put it in correctly again. Be shure you put the lid on fuelpump with the fuel-intake in 4 o klock position.

Gas pressure from pump shall be 3,5-6 psi ( higer number on WOT).

Is carbs ok. ?.



Electric:


Spark on all 3 cylinders?.

If thats okay.

Timing?

Take out number one spark plug put in a long srewdriver, turn engine around WITH HAND no key in key switch, and feel when piston in top TDC, now you shall see that timing mark on flytwheel is 0 right in front of flywheel and pointing on the timing mark on the engine in front.

Why i writing this is becaurse it?s often the flywheel key on this engine is broken, if the engine have been force top stop suddenly becaurse for example someone sucked in a whater skii line in the impeller.

8-10 degrees. on ideling

30 on WOT checking with lamp on number 1 cyl spark plug line.



Regards Anders

 

[Part-time]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Hand held tack...
A unit like this, it has an inductive pick up that you connect to number one spark plug wire.

 

[e-spin]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

I have been fooled more than once by how well these engines seem to run on just two cylinders. It would be good to know if your are firing on all cylinders and if you are able to turn at 5k rpms in the water, which is about the min. to plane out on my searayder 14.

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Also check the sealing on side of pump unit in back end of boat, both sides. There i had a leak on mine sucked exhaust-gas down making the pump cavitate/ loose the grip in whater.

What seal are you talking about? The FOAM-Exhaust Deflector? Thats the seal that goes between the pump and the boat in the back.

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

BTW took the fuel pump apart to give it a check and all is good. I have spark on all three holes, I knew it would with the switchbox and coils being new.

 

[aksor]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

I just installed a tachometer on my 90 sportjet I got one from Telef lex it has adjustments in the back for our motor.

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Ive been looking all night and cant find anything. What model tach did you buy so i know what im looking for?

 

[Anders67]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

What seal are you talking about? The FOAM-Exhaust Deflector? Thats the seal that goes between the pump and the boat in the back.

Yes that one. On mine you could see on the hull on side of pump, that it was a little black-ed of exhaust gas.





But if it?s the pump unit that is the problem, i repeat. You shall hear the engine on WOT hit the top rpm. , and the rev limiter shall cut the ingnition.

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Yes that one. On mine you could see on the hull on side of pump, that it was a little black-ed of exhaust gas.





But if it?s the pump unit that is the problem, i repeat. You shall hear the engine on WOT hit the top rpm. , and the rev limiter shall cut the ingnition.

Never heard of that seal causeing the problem.

When i go WOT the boat revs up but the boat wont plane out or gain any kind of speed. The rev limiter has never seemed to cut any of the ingnition out or anything that i know of. Is the rev limiter the causeing problem? maybe that rev limiter is bad and not letting the boat rev up to what it needs to to plane out and gain speed?

 

[Anders67]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

Hi again .


No i know. I?m seem to be a consult of tec. breakdown on mine tec.- things, that no people have heard of (on cars, snowmobiles, boat engines, motorcycles, et.c ). :facepalm:


Now , the rew limiter you can just disconnect, and see if it helps. Just for test. You see it on left side a black box just beside the reticifer.


If you hear the rew limiter cut in as it shall, the engine sounds like row-row-row-row. hitting top rpm. and then falls a litte and goes upp and hit top again, atomaticly.

Check your spark timing, so thats right.


You don?t have some other stuff hanging down in whater from the boat??. In back for example. like bolt on drop-down swim- ladder?.


Just try to help. Regards

 

[Trailratethisfx4]

Re: Sport Jet 90 Will not plane and has no speed, HELP!

I really appreciate the help.

My boat doesnt do the row-row-row-row noise when the throttle is all the way down. it just hit a certain tone and stays there.

There is nothing hanging down.

Really dont know what to do or look at anymore.