Ski runs like crap when the tank is full, but it runs better when empty?

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
I didn't advance it. Keeping it stock until I legitimately check it with a timing light and then I'll advance it a couple degrees.
 
Location
Stockton
Well a buddy hooked me up with a stator out of his old ski for free..don't think he would lie about the condition lol.

Assuming parts are good is no way to trouble shoot an issue.

It was nice your friend donated the stator, he's trying to help you. May I ask How old was his old ski? In other words how long had it been since he used the stator and did his old ski have any symptoms ? Did you just inherent something he may have thought was a carb issue or something else?

Ya the short might have effected something, the pro tec Cdi is it a part you for sure know to be good? have you used it before without issue?

The only part I could ship you to try out of those three is a 96 up superjet coil or fuel tank, external fuel pump, internal fuel fill with clunks
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
Yeah @Harbor has been extremely helpful, along with @Pro-pulsion . I'm gonna run it with just a little bit of gas and see if it runs great again though, first. Rather not pull my stator off if I don't have to. I'm anxious to know what would be wrong with my stator that would cause an issue like this. Usually it seems like electrical issues occur when the ski gets warm..
I'm leaning to a coil issue or a fuel issue.
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
Assuming parts are good is no way to trouble shoot an issue.

It was nice your friend donated the stator, he's trying to help you. May I ask How old was his old ski? In other words how long had it been since he used the stator and did his old ski have any symptoms ? Did you just inherent something he may have thought was a carb issue or something else?

Ya the short might have effected something, the pro tec Cdi is it a part you for sure know to be good? have you used it before without issue?

The only part I could ship you to try out of those three is a 96 up superjet coil or fuel tank, external fuel pump, internal fuel fill with clunks
Just messaged him about it-he said it ran absolutely perfect when he took it off. The protec is known good. I've been using it for over a year. Yeah none of that would really work I don't think. I have a spare coil that I rewired and then my engine blew up that day..Could try that. I really really appreciate your guys's help..
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
^^^^ maybe do one gallon first, if it runs good do another gallon, then another, then fill the tank and see if it changes
Will do! Gahh this is just a wierd thing. If this is somehow an electrical issue, I feel like it would get worse as it heats up..not get better.
 

Joker

...chaos? Its Fair!
Yeah @Harbor has been extremely helpful, along with @Pro-pulsion . Usually it seems like electrical issues occur when the ski gets warm..
I'm leaning to a coil issue or a fuel issue.

Didn't you just say it usually gets worse as it heats up? Once you do the gallon by gallon test. Take a volt meter to stator and plus wires. Test resistance on the plus wires starting at full length. If one is different from another you should be able to pin point the bad portion of the wire by reducing the distance between the leads until you find an area with a really high resistance compared to areas with low resistance.
 

Joker

...chaos? Its Fair!
If that's true it has to be fuel. Water ingestion could be an option too. It is able to clear the moisture better when it's hot. I like the idea of checking your head pipe and mani for cracks that could put water back into the exhaust
 

rubbertoe

X-H20 certified
Location
San Diego
Rosand have you ever had water in your gas ? almost everyone i know who runs a a stock fuel fill and does stabs or subs at one point or another suffers from water getting in the tank ,also could be a cracked fuel fill neck .your boat may only be in the water at a certain fuel level or when its sloshing ,check all fuel lines for leaks ,pick ups ect. idk .its such an easy thing to rule out before wasting time on other things .One thing that bugs about problem threads (4 pages of this ? are you kidding me ? )such as these is when people try to help ,but diagnosis suggestions are just stubbornly refused why bother to ask everyone if you know what it is ,right ? just check it replace it what ever just please stop chitter chatter on the thread and go work on your ski ,till its fixed .
 
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Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
That escalated quickly.. Yes I have had water in my gas before.. I'll siphon the rest of the gas out of my tank and check to make sure it's sealed and see if there's any water in it.
Why 4 pages? Because it's a different issue than I've heard of before and obviously it's something people have had to do some thinking about, and people have been willing to help. Stubbornly refused? I'm not stubbornly refusing anything at all, i rule out stuff that doesn't make any sense and I try to think about how that issue would actually cause my symptoms. I like to critically think rather than just trial and error but that's just me.. @Harbor and @Pro-pulsion do the same.. Maybe I forgot to tighten down the hose clamp on my filler neck, so after an impact(when the tank is full) it partially slips and the pressure leaks out, and when it's close to empty it barely after an impact. That would cause propulsions theory if it wasn't a fuel pump issue.
@rubbertoe, if it was still summertime I'd be constantly trying different things out and wouldn't be chattering but I have zero time to work on my ski during the week, and very limited time on the weekends.. So IMO it's good to have a bunch of ideas brainstormed to problem solve what's going on during the week. There's been some awesome ideas raised here..
Don't know why you had to freak out about it. If you don't wanna hear about what's going on, then don't click on the thread and take out your anger. Not cool man!
 
Location
Stockton
You might have a look at the fuel cap and seal while your in there, @rubbertoe brought up a good point about water entering the fuel system while the noise in submerged
 
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