1995 GTX loss of power at WOT, new fuel lines?

[boxchevyman]

Hi All!
I have a 1995 GTX that I’m having some trouble with. When I first got it would surge and bog at WOT. So I replaced the fuel lines and bypassed the fuel water separator as it was leaking. The Ski ran great for the weekend. At the end of the weekend my starter solenoid crapped out so I put a new one in. So I take it out today and it is like cutting out at WOT but it’s like a loss of power more than bogging down if that makes sense? I pulled the choke out and the behavior didn’t change besides bogging down from too much fuel…
Here is what I have checked.

Compression is 140 on both cylinders.
New spark plugs.
New black fuel lines and clear fuel filter inline to carb (I bypassed the water separator though)
New solenoid (maybe I bumped something in there?)

So I’m a bit at a loss. This acts like a fuel problem but I have plenty of fuel in my clear fuel filter.
Also starting now I have one long beep coming from the seadoo at startup. If I just push on the start button without having the lanyard attached the beep is continuous until I put the lanyard on. Might be totally unrelated but it didn’t used to do that so I thought I would mention it.

Thanks for all your help,
James

 

[Coastiejoe]

Did you open the carbs up, clean the filters, new OEM gaskets. Clean it replace the fuel selector when you did the lines? If not, that's your next step.

 

[boxchevyman]

Hi Joe,

Thanks for replying.

I have opened the carbs up to the clean the filter screens and then I installed a framm inline fuel filter in front of the carbs. I have not replaced any gasket in the carb or otherwise rebuilt the carbs. Although they looked great.

I did clean the fuel selector valve. And I can blow air through all ways.

I feel good about the gas flow up to the carbs and my thinking is, I can see the flow through the inline filter, also the choke has no effect on the cutting out. So I really don't think its running lean.

I could be wrong and im asking because I don't know much about seadoo's but my gut says its at least behaving differently than a tradition lean condition.

Again I could be totally off base here.

 

[Coastiejoe]

For now, bypass the fuel selector. They fail often. Lets eliminate it temporarily.

 

[Coastiejoe]

Rectifiers fail and cause running issues. Unplug it for a test run.

 

[boxchevyman]

Just went out to check the rectifier, i have 13.85 volts DC steady at all RPMs. So im guessing that's OK? It could be fuel... I will decarb the motor tomorrow night and check them all out.

 

[Coastiejoe]

When they fail they still charge but put out a small amour of AC voltage. The AC volts screws with the MPEM.

 

[boxchevyman]

Ok so im going to the river tonight to run some tests.

Im going to disconect the red wire from the rectifer to see if problem goes away.
Then im going to run it without the seat on to watch the fuel flow in the clear fuel filter.
I will pull the choke out again and see if it helps i aldready did that but ill do it again.

Is there anything else you would suggest doing?

Thanks
James

 

[Coastiejoe]

Not off hand. Do those and let us know.

When the rectifier is unplug it won't charge, you will be running off your battery.

 

[Mekanix]

Another compression check.
140 is a bit low. Im wondering if your feeling of loosing power is just the engine getting tired after its hot.
An overheated engine, low compression or one that has leaned out too many times and scored the cylinders will give you some good power but will feel like its fading the more you run it while its up to temp.

 

[Coastiejoe]

140 is fine.. Just always good to know rather than to guess. Just trying to eliminate common issues at this point..

 

[boxchevyman]

Ok i will retest the compression. The feeling of power loss is almost like a sudden jerk. Like cavitation only the rpms go down.

However the compression test was done when i bought the ski in march. I took one 5 minute ride and saw it bogging out so i replaceced the fuel lines. Then i have put about 1 maybe 2 hours of use on it. So im hopping it hasent changed much. But i have a gauge in my box so i can retest it just for grins and gigles.

When i was researching the ski i saw 150 is what its supposed to have and 135 was close to rebuild time. So i thought i was ok with 140 on a 22 year old ski?

 

[Coastiejoe]

125 is even acceptable. At 120 you will be in need of some sort of engine work..

 

[boxchevyman]

Ok so i got home and did a quick compression check. I have 140 on mag side and 142ish on pto side.

I went to the river. this things starts great just a push of the button after you choke it the first time. anyways ran it at full throttle and the problem happened immediately. pulled choke out and i cant even get it to run with any amount of choke it just bogs down when you apply choke.

So i took the seat off and went full throttle no change.
I looked at the fuel filter and the gas stayed at the top of the fuel filter didn't run dry.
Switched from gas to reserve and no change.
Then i went back to the ramp and took the grey box out and disconnected the red wire from the rectifier and put tape around the exposed end just in case it hit anything in the case. NO CHANGE.

Just so i can be clear in describing the problem, It goes to plane and will suddenly "stumble". Its an irregular misfire like stumble, where as a rev limiter would be even and calculated this miss occurs at various rpm ranges. it is noticeable all the way down to half throttle. Which makes me think electrical of some kind?

Thanks for all your help,
James

 

[boxchevyman]

How do these spark plugs look? they have about 2 hours on them.

 

[boxchevyman]

Does anybody have a diagnostic guide for the electrical system?
Or any tips on how i should go about testing for a no spark situation at high rpm on the water?

Thanks

 

[kevinz]

I'll take a stab at it here...those plugs look a little lean to me. However, the best way to check plugs on one of these things is to run it at WOT on the water and then while still at WOT, pull the lanyard or press the start/stop button to kill the engine. Let it coast to a stop, then pull the plugs. This is called a plug chop. However, in your case this may not work as it doesn't sound like you can even run WOT.

I have a Polaris Virage that was exhibiting some similar symptoms. I also replaced everything in the fuel system as you did. I would advise rebuilding the carbs because even though the internal parts may look OK, they are still 21 years old. Remember, just because fuel is making it to the filter doesn't mean the correct amount is actually going through the carbs and into the engine. All filling the filter up tells you is the fuel pump works. Set the low and high speed mixture screws to stock and try it then. On my Virage, I had to play with the low speed screw a little, but there's a lot of debate over the accuracy of the specs from Polaris (unrelated topic for another time LOL).

 

[pwgsx]

plugs look lean to me, not horrible but the left is lean for sure

 

[boxchevyman]

Ok im completely fine with rebuilding the carbs. Just want to make sure it still make sense even though when i pull on the choke at all it starts to die?

Stupid question could water in gas cause any of this? I did take out the water fuel seperator...

But this will be the third time ive been told to rebuild the carbs so i guess ill just get the kit on its way.

 

[drewski]

I have 2 95 gtx machines. One was doing the exact same thing. I bypassed the fuel selector, problem solved. Replaced for about 20 bucks.

 

[1983]

If carbs have not been rebuilt, then stop what you are doing and order OEM mikuni kits ASAP.

 

[kevinz]

Ok im completely fine with rebuilding the carbs. Just want to make sure it still make sense even though when i pull on the choke at all it starts to die?

Stupid question could water in gas cause any of this? I did take out the water fuel seperator...

But this will be the third time ive been told to rebuild the carbs so i guess ill just get the kit on its way.

I personally have never had much luck with the pull the choke while running method. I would get the carbs and the fuel selector valve in top shape. Water in fuel could be a possibility...I took the water/fuel separator out of my 1996 GTi last year for a short while and didn't have any issues...

On that note, there is a little o ring in the separator that seals the bowl to the lid. That o-ring is known for tearing due to age and repeated removal/installation of the bowl. Some say that can cause an air leak, which I certainly agree it could, just never experienced it as when I reinstalled mine, I got new o rings from the dealer. They can be had for usually a couple of bucks; I got two just so I had a spare.

 

[boxchevyman]

Hi all,

So I have being thinking about this all day and the more i think about the problem the more i think it is spark. So i did some research and thought i would regap the plugs and trim the plug wires. Then if that didn't work i would disconnect the rev limiter to see if that was a problem.

So i re-gaped the plugs they were .30 vs .20 that the manual spec. Then i trimmed the plug wires. One of the plug wires actually fell out when i was messing with putting the rectifier wire back on so i was kinda forced to do that one.

So i took it to the river and it works great! Never messed with disconnecting the rev limiter since it ran great. My guess is when i replaced the starter solenoid i pulled one of the plug wires out of the boot and i got intermittent spark.

I didn't realize the boot was different from automotive types where it takes a big pull to separate the the wire from the plug ring.

Anyways i now have a buzzer going off all the time but im going to start a new thread on that.

Just wanted to say thanks for all the good tips and advice,
James

 

[Kal Brigger]

What do you mean by trim the plug wires?

I'm having some of the same issues you're having so I'm wondering if I should look at my wires.

 

[Luv2Camp]

What do you mean by trim the plug wires?

I'm having some of the same issues you're having so I'm wondering if I should look at my wires.

The plug boots screw into the plug wires. You can remove the boot, trim back the wire a little and screw the boot back on. I use zip ties as well on the boot end when done. Just be sure you do not trim too much off where you do not have enough length to get the boot back on the plug when done.

On a side not to the op, the plugs still look lean so I would check them again now that you think you have corrected the problem