1996 787 GTX will not run right - Blogs - PWCToday

» Log in

User Name:


Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

View RSS Feed

Normster 50

1996 787 GTX will not run right

Rate this Entry
Bought a used 1996 GTX 787 a couple years ago and am having trouble getting it to run smooth. I ran it for most of the summer when I purchased it and it ran real good, towards fall (after about 10 -12 rides) my kids told me it started to bog a bit getting out of the hole but once it cleaned it self out/warmed up the bog was gone. I did some research online and realized it still had grey gas lines so during the winter I replaced all the fuel lines and rebuilt the carbs with carb kits I purchased online. I fired it up after the repairs and it seem to run real good again. About a week later I fired it up again and it had a bad bottom end bog again. When it first fires up it will rev to about 7000 for a split second then pretty much instantly bogs down to about 3000 then wont rev above 3000, just like its running on one cylinder. I tried giving it a little choke when its bogging and it stalls, makes it worse so i'm thinking its rich, however if its lean and only running on one cylinder it could be flooding the one cylinder thats getting the fuel, perhaps its lean? It will fire up pretty much everytime I start it but just wont get going. The plugs are wet and it smokes heavy when its bogging, I can also smell raw fuel so it appears it may be flooding on one side.

At this time I decided to buy 2 more ďgenuine mikuniĒ carb kits online and replace the generic ones I bought, I read they needed to be genuine mikuni or they wouldnít work so I ensured the ones I bought were, they were shipped in mikuni packaging so I assume they are genuine mikuni, plus the new ones fuel pump valves/discs are softer than the generic ones. I fired it up again and it seemed to run real good, I waited a few days tried it again and it was back to bogging again. For the record I ensured I put the valves for the fuel pump in correctly based on the blue line down on the disc/valve, I believe it was the marked side went against the carb. NOTE: There wasnít really a bunch of green slime anywhere when I changed the fuel lines. When it seemed to be running OK I took it on the water and I could get about 30 mph out of it but I had to accelerate extremely slowly, like I mean slooowly, and if I tried to exceed 30 mph it would just die, it would go again after it fell on its face if I feathered the throttle, basically it would go about 25-30 ish mph at approx ľ throttle and that was it. If I tried to hammer the throttle it would just die. It was also sputtering at low end so I shut it down worrying I would blow it up.

PS. I noticed the heads and jugs had been removed so Iím not sure why it was ripped apart, the fellow I bought it from said he bought it from his wealthy neighbour so it was always maintained if/when needed. I think it may have just got a new top end installed but I cant say for sure, has +/- 160 & 162 compression. Iím the third owner, the fellow I bought it form said it ran fine for him.

Iím baffled, hereís a list of things I have done to date.
Installed new fuel lines. Installed new ďgenuine mikuniĒ carb kits, Low speed screws at 1ľ turns out and high speed closed (as per spec), new needles and seats (seats are 2.0) and set pop off at 28 psi, replaced the original seats to see if it would make a difference and it didnít. The original seats sealed fine, they also appeared a bit smaller diameter, couldnít find any markings on them, runs the same with either of the seats used. I bought the seats new online and according to the add they were for a 1996 787 GTX and a couple other 787 models, or so the add said. When I rebuilt the carbs for the second/third time I manually cleaned the carbs and blew air through all the ports, everything appears to be fine/unplugged. Tried a new coil but it didnít make a difference so I removed it and reinstalled the old one. Trimmed back the plug wires and reinstalled plug boots, no change. Cleaned the raves. New fuel filter and oring. Removed selector switch and it was clear, cleaned it out anyways just to make sure, tried running the ski in both on and res and it didnít make a difference. New impeller and wear ring.

I took it to a reputable dealer and they messed with it for a couple days and couldnít get it figured out, they pretty much did the same things I did, they also ran some electrical checks to ensure everything was proper. They told me it ran OK when they hooked it up to a remote gas can with a primer ball and kept pumping the fuel to it. Is it possible thereís something up with the built in fuel pump? Could I possibly install a high flow external fuel pump and gut the fuel pump in the first carb, or just install another pump upstream of the carb as a booster pump. If I do will there be enough vacuum to run both pumps?

I spent $1500 at the dealership last year and didnít really get anywhere. I have a 1997 GSX as well with the same motor and carb setup, I was thinking of switching everything from the GSX to the GTX just so I know whether or not itís the carbs, however I am concerned I could end up with 2 machines that donít work and the GSX runs excellent so I donít really want to mess with it. Iím going to try draining the fuel, some of the fuel in it could be old. I never did drain it completely and start with fresh fuel, its possible thereís water in the fuel as well, but if this was the case why would it run good with the external ball primer pump feeding the carbs. Donít really think fuel is the issue but never know. Thinking I may just need to get it on the lake dump some STP carb cleaner in fresh fuel and take it for a good run, if I can get it to run.

I'm running out of ideas so any help would be "GREATLY" appreciated. Thanks in advance.
Tags: None Add / Edit Tags


Powered by vBadvanced CMPS v4.2.0