96 gtx won't accelerate

[Nieo]

Hi I have a 96 seadoo gtx with a new engine that won't accelerate or run right when it is given WOT it will probably get around 3000 rpm (not sure rpm gauge doesn't work) and will push water as if it is about to get up on plane but won't. I have gotten it on plane a couple of times but as soon as you turn it will drop back down and is not able to get on plane again.

no gray fuel lines
filter is good
carbs have been rebuilt
jet pump has been gone through and is in good condition
compression is good
spark is good
runs on both cylinders
timing has been checked
jets have been messed around with and don't make a difference

anyone have any ideas I am running out
engine is currently out of the ski for a crank case leak down test

 

[Nieo]

the ski was converted to premix when I put the new engine in

 

[POPPS]

What do you mean "the jets have been messed around?",,the jets should be stock. Rule out sticking rav valves,
Does the crank rotate freely with the plugs out?Dod you try running fuel directly to the carb from the fuel pickup?

 

[etemplet]

With our GTXs I found that a Carburetor Pop-Off of 36-38psi worked best. When rebuilding the carbs were the streams in the carb barrel checked for flow? You should see all 3 with good flow. My wife's GTX had a lot of issues with the transition.

My first rebuild was with a kit that said "Mikuni" but wasn't genuine Mikuni parts. The true fix came after I replaced everything with genuine parts. Good Luck.

 

[Nieo]

I have ran fuel directly to carbs and jets have been adjusted within all possible spec. crank does rotate freely

carbs have good flow in the barrel
my pop off pressure is 23 and 25 psi is that to low and could be causing the problem I couldn't find the spec

thanks for the help

 

[Nieo]

if the pop off pressure is the issue where would you recommend I get the new springs from?

 

[etemplet]

I think @mikidymac could help with where to buy the springs and which ones. My skis, both of the responded much better and the final fix the cargs Popped off at 37-ish with hardly any leakdown after popping. I'm not pisitive but I think the 787 GTX takes the black 85 grm springs. I like to replace the needles seat as well (1.5)

 

[Nieo]

Finally got around to replacing the spring and tested the pop off it is now at 30ish for both and tested it with the same problem anyone have any other ideas

thanks

 

[emspjay]

Rectifier, when the one went bad in my wife's GTX it wouldn't rev up.

 

[Nieo]

Is there a way to test the rectifier

 

[emspjay]

I think you just have to unplug the red wire on it, but that also means it is just running off the battery so don't do it for long. Do a search for rectifier and there should be a thread.

 

[Nieo]

Alright I ran it with the red wire disconnected on the rectifier and still does the same thing could the rectifier still be the problem and I just need to buy a new one

 

[emspjay]

I would check the Rave valves before buying a rectifier if there was no change. There was a problem with Raves on the 1997 GTX but I don't think the 1996 was affected.

 

[emspjay]

Info on Raves in below thread.

1997 GTX struggles to rev past 4500 rpm

 

[Lothsahn]

If unplugging the red wire on the rectifier didn't fix it, the rectifier isn't the issue. But if you want to be sure do a rectifier check.

Check rave valves. Pull them and make sure they're clean and the tension is set right. Look up the procedure on the forum here or download the service manual. If the raves don't open you won't get good power, but I thought it'd max around 4000-4500 rpm, not 3000.

Have you verified at WOT that the carb butterflies are fully open?

 

[fatblockabody]

Any update on this? Similar issue going on with a 97 I'm just finishing restoring

 

[Lothsahn]

Any update on this? Similar issue going on with a 97 I'm just finishing restoring

The most common problem is the rectifier. The OP checked his, but have you watched the video and checked yours? It's very easy to check, fix, and replacements are cheap.

 

[fatblockabody]

Yes, swapped rectifier with known good, all new fuel filters and lines, carbs rebuilt with OEM, swapped water regulator with known good, cleaned my slotted RAVES, RV timing correct, pump good, compression good, wires good.

Next test for me is the fuel selector(tomorrow). It does it on reserve and 'ON'. Pro of having 3, 787 ski's is the ability to swap stuff around non stop until I find the issue.

 

[Lothsahn]

That's the usual suspects. Try unplugging red wire from rectifier next time you're out. Maybe something is wrong with the stator?

What color are the plugs? Are your carb jets the right size? Did someone swap them? All jets clean?

 

[fatblockabody]

That's the plan.

Plugs are new so no color yet. Stock jets, No, Yes.

 

[Lothsahn]

That's the plan.

Plugs are new so no color yet. Stock jets, No, Yes.

Make sure you have a good battery too. Low/high voltage will cause all sorts of problems.

 

[7mmremmag]

Brand new NAPA AGMs in all my ski's on tenders when not in use.

 

[Nieo]

Alright rectifier is not the issue butterfly valves in the carbs are also fully open at WOT. Going through the raves tomorrow really hoping to find them stuck

 

[Nieo]

I pulled the raves out this morning or one the exhaust blocks the other and the back cylinder race was clean with nothing in it when I pulled the front one out it was very dark and a little oily pulled the plugs and same story back one was clean like it should look front was dark is my front running way to rich and it is a carb problem? Both pairs of jets on the carbs are set the same

 

[fatblockabody]

Figured out my similar issue..... My 'known good' water regulator must of been on it's way out and became 'not a known good' when I was changing them.