Super Jet SN dying when putting weight in the tray(rear)?

[NorCalSJ]

Trying to help my friend fix his ski he has a 1990 SN, it runs fine idling flat in the water but soon as you hop into the tray and the nose goes up it starts sputtering and dies. The only thing that makes since to me is a fuel issue? Gas tank is full of fresh gas. Last ride it only lasted 5min he fell off and ski wouldnt refire. Any ideas or suggestions would be greatly appreciated.

Steve

 

[Quinc]

Trying to help my friend fix his ski he has a 1990 SN, it runs fine idling flat in the water but soon as you hop into the tray and the nose goes up it starts sputtering and dies. The only thing that makes since to me is a fuel issue? Gas tank is full of fresh gas. Last ride it only lasted 5min he fell off and ski wouldnt refire. Any ideas or suggestions would be greatly appreciated.

Steve

Check all your fuel lines, and make sure its not getting air in somewhere. Included the lines that are in your tank. Also try switching between Reserve and On. Make sure all of your lines are tight on your Carb.

 

[aytee]

Trying to help my friend fix his ski he has a 1990 SN, it runs fine idling flat in the water but soon as you hop into the tray and the nose goes up it starts sputtering and dies. The only thing that makes since to me is a fuel issue? Gas tank is full of fresh gas. Last ride it only lasted 5min he fell off and ski wouldnt refire. Any ideas or suggestions would be greatly appreciated.

Steve

just ride on the hood... haha... i'd start with the reserve/on option and go from there..

 

[NorCalSJ]

Replaced all the fuel lines. I am stumped any other ideas? It runs fine out of water or flat in the water but soon as you tilt it it sputters and dies shortly after Anyone else experience this?

 

[Scraggly]

Trash in the carb or water in the system would be my first place to look.

 

[Tyrant1919]

Perhaps something exhaust related once the water covers the exhaust pipe. Just spit-balling here for you.

 

[ajmps1]

it runs fine on a hose? what do the plugs look like, white, brown, black,pitted? should probly just rebuild the carb anyway. you can give it throttle on a stand on the hose and it runs? whats the compression? theres alot you gotta do still. you replaced the lines inside the tank too? is there crap in the tank that sloshes backwards when in motion clogging up the line? in which case the filter would be filthy and the carb would need a good cleaning and rebuild...

 

[aytee]

as stated, it could be a number of things at this point... how far can you tilt it before it acts up? does it act up if you hold onto it and get on the throttle? if you didn't do the lines inside the lines inside the tank, your pickup could be hung up(picking up fuel when level and not picking up when not level)... also how much fuel is in it?(i'm not saying you're problem is simply out of fuel, just trying to get everyone as much info as possible) that's an easy way to eliminate line leaks inside the tank and pick up issues...

 

[orangefinger]

have u checked for exhaust leak ??? if no backpressure on exhaust ( outside water ok ) and in water ( backpressure ) exhaust leaks into engine compartment ...??

 

[NorCalSJ]

We emptied the tank and checked the pick ups everything looked good. If its exhaust related which is what I'm leaning towards now where do I start, what am I looking for? It doesn't take much of a tilt for it to die just pushing the tray down a few inches will cause it to die quickly. Last night it started up easy out of the water 5 minutes later we put it in the water and it didn't want to start just sitting flat it took a minute for it to finally start. Took it back out of the water started up and seemed to have quite a bit of water coming out of the exhaust?

 

[Tyrant1919]

Things I'm thinking:

Is it tilt related? Does the ski run ok when tilted out of the water? I know skis run a lot easier out of the water, but maybe if it's something stupid you can notice it.
Is there a gasket blown somewhere? I'd take the head and exaust manifold off and check for a leak. A lot of water in the exaust may indicate a leak. I'm leaning towards exaust gasket leak and not a head leak. When running slow water can probably more easily shoot into the combustion chamber, when running a bit more at speed, the exaust gases probably blow the leaking water away from the combustion chamber. I'll take leaking exaust gasket for $800!

 

[NorCalSJ]

So a leaking exhaust gasket would kill the back pressure and cause it to die?

 

[Tyrant1919]

I'm not sure if it's killing the back pressure or actually getting in the combustion chamber. I'm just speculating as I'm no expert, but I'm guessing a gasket issue. Your comment of excessive water in the exhaust kinda led me that way. I read your post wrong at first so my comments above maybe in correct.

Maybe when it's idling, the water 'leaking' through the gasket isn't much, so it runs alright. As you jump on and give it a little gas it increases the water flow through the 'leak' and gives you issues.

Just guessing. But I enjoy a good puzzle from time to time.

 

[lanmine657]

you may have water sloshing around in the ebox shorting out the coil

 

[Tyrant1919]

Yeah, I'd check the ebox too.

 

[aytee]

get it started out of the water and place your hand over the exhaust outlet to the point you're creating back pressure if it dies then, it's pressure related.. if it doesn't it's water related... that's about the simplest trial and error test i can come up with... also, check the plugs...

 

[NorCalSJ]

Ebox and plugs look fine. I'll try that test thanks

 

[The Penguin]

So a leaking exhaust gasket would kill the back pressure and cause it to die?

not necessarily lack of back pressure. lack of oxygen.

engine compartment fills with exhaust, and exhaust starts going back into engine. It won't ignite fuel, so engine dies.

you pull off hood and everything seems to work fine.

try riding it without hood, in the water and see if it dies. If it does not - you have an exhaust leak.

my guess would be the long exhaust tube.

 

[aramis]

if it turns out to be engine load related (and not really tilt related), be sure to check for a busted reed valve...

 

[NorCalSJ]

It started up right away today after sitting over night and had water pouring out the pipe after all the water got out I put a rag In the exhaust and it died so that would be pressure related? Would that be a blown gasket?