Ok, my ski is a 96 Gsx 787cc. I bought it a few months ago and being my first jet ski its been a learning experince, I am a Chrysler service tech so Im mechanically incline but these jetski's are a different animal lol. I have enjoyed it so far but have started having some problems so I decided to tear into it. First off, I have a oil leak in the hull coming from somewhere so after reading about the oil tank grommet that leaks I pulled the tank and replaced it and checked all the lines. Reinstalled and put a quart in it and marked the tank and let it set overnight and it sure enough leaked out. I do think I found the leak though, I was feeling around and found the bottom of the oil pump/linkage soaking wet with oil. My question is how does that come off, I dont really see or feel any bolts? Is there a gasket or seal there? Next, when I first get it out on the river, it idles fine, starts ok, but wont go over 4-5k rpm for like 20-30mins then all of a sudden boom wide open 6400 rpms. I tried a voltage regulator and it didnt fix it. So i figure its gotta be in the carbs and lines, replaced the lines, I pulled the carbs them and took them apart and cleaned everything, filters, jets, ect... nothing was broke, cracked, ect.. Went to install them and noticed there are no carb base gaskets at all, is there supposed to be? Also what rpm should I be seeing at WOT? Thanks for any help.
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96 gsx, couple of questions, need help.
- Thread starter jd96gsx
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Opformark
New Member
There should for sure be a base gasket. Also you should see 6700 rpm on a good running 787. Make sure the feed line to your pump isn't leaking. Either at the pump or possibly at the tank as the oil will follow the line to the lowest point and then leak. The rave vales are real important on these motors so I'd check them right away as well. They might be gummed up and not moving till they see enough temp to not be so sticky. Good luck and let us know how it goes.
Does the oil pump have two Allen head bolts that hold it on? I think one came out, I found one laying in the hull.
try looking at this. Parts #27 & 28 are the bolts you may be referring to. Click on parts on top of page then search form your ski/boat.
http://fiche.seadoowarehouse.com/se...lid=1996 Sea Doo PWC GSX MAGNETO AND OIL PUMP
http://fiche.seadoowarehouse.com/se...lid=1996 Sea Doo PWC GSX MAGNETO AND OIL PUMP
brock1
New Member
ok...on a 787 you should see about 6900 rpm's with no problem...so...to start ...if there is no oil laying in the hull then its most likely your center crank seals...does it smoke alot on startup if it sits for a week or so??? as for the rpm problem if you are only geting 4-5 that sounds to me like your raves are not opening..when was the last timne you took them apart and cleaned them??? and yes you are supposed to have base gaskets on those carbs...you should feel very fortunate that your engine is still running...how do yourplugs look?? are they white colored after a WOT run
Its def leaking in the hull, its coming from the oil pump, I think there is a bolt missing causing it not to seal. It doesnt smoke bad at start up at all, about normal. When it does run ok, I still at the max see 6500 rpm. Yea having no carb gaskets I figure would cause a lean condition, Im really suprised it even idled ok.
brock1
New Member
ok...well there are 2 allen style bolts that hold the pump on check and see if they are tight...also check to see if the bleeder screw is loose...if all that is ok check and see if the line is leaking going into the pump it should have a clamp on it......so did you read what i said about the raves??? have you cleaned them??
There isnt a clamp on the inlet hose at the pump, there was a ziptie and it was too low on the hose, I put a ziptie in the right spot. Its gonna be a bitch to put a clamp on it but i can tell it had one on it before. And no I havent cleaned the rave valve but im gonna tonight. Do i need to buy anything to do this? Gaskets??
brock1
New Member
the housing gaskets may need to be replaced if they have never been before but you wont know until you get them off...i personally always replace mine but if they look good and are not ripped then you might be able to get away with not doing it....to clean them i just use carb cleaned and some steel wool..just spray and rub with the steel wool...be sure to check the bellows and make sure they dont have holes in them and chec the springs
One more question. The previous owner pre mixed because he said he didnt trust the oil injection. Now that I found the leak apparently he knew about, now im thinking it will be fine with the leak fixed. Since the carbs are off, can I spin the engine over and hold the oil pump wide open and see if oil comes out the nozzel by the rotary valve? Will it hurt anything? Also If I was to just premix, can I just block off the oil line with the filter and leave the one that goes to the rotary valve hooked up? Will it hurt to leave the pump on there just no oil fed to it?
Strizzo
Well-Known Member
the pump will pump oil when the motor is not running. i had a small bubble in one of my lines, so i pulled the plugs and cranked it over with the lever at wide open and watched the bubble move through the line. it won't pump as much oil obviously but it will still move oil.
If I just block off the oil supply line from the tank to the pump and leave the line to the rotary valve hooked up will that cause any problem? I think im gonna stick to premix, because I think I need a pump and really dont want to mess with it right now and seeing as ive been premixing for a few months anyway, and its ran ok. I will by a block off plate eventually but will it be ok to just block the line off and leave the pump on there?
Strizzo
Well-Known Member
If you just block the oil flow to the pump it will definitely lunch itself and could cause other issues. The 787 has a little plastic coupler behind it that drives the pump off the crank. If you pull the pump off and remove the coupler, you can leave the rest hooked up and just leave the pump on the mag housing and save 12 bucks on a block off plate.
I'm wondering how this cat changed over to pre-mix. To properly do it you need to at least remove the oil pump drive and cap the oil supply nozzles from the outside of the rotary valve housing. If you don't remove the drive but disconnect the supply line you'll BBQ the pump in no time.
So if you want to properly do it, buy a block off kit, remove the MAG cover and remove the plastic oil pump drive. Install the cover with the block off plate, then cap the two nozzle feeds. And pre-mix the gas. You'l also have to plug the supply line for the oil pump, but you NEED to leave the supply and return for the rotary valve cavity---that HAS to have oil. Some guys do a loop and remove the oil tank all together, I prefer to leave the tank--easy to spot the oil useage if there were any down the road from crank seals going bad. Simply mark the tank and check against that line when you go to ride everytime.
So if you want to properly do it, buy a block off kit, remove the MAG cover and remove the plastic oil pump drive. Install the cover with the block off plate, then cap the two nozzle feeds. And pre-mix the gas. You'l also have to plug the supply line for the oil pump, but you NEED to leave the supply and return for the rotary valve cavity---that HAS to have oil. Some guys do a loop and remove the oil tank all together, I prefer to leave the tank--easy to spot the oil useage if there were any down the road from crank seals going bad. Simply mark the tank and check against that line when you go to ride everytime.
The reason I want to do this is because the pump linkage just spins like the spring is broke, so I'm pretty sure I need one. I might just fix it instead. I bought two ski's from this guy the seadoo and a 96 Yamaha wave venture 1100 both have had the top end rebuilt by him and both on premix and the injection system obviously. I'm just now figuring out the seadoo but haven't even began on the Yamaha which runs fine but I'm sure I'll find some issues with after looking at this one.
Ok test rode my ski today, same issue first 30-45 mins damn thing won't hardly hit 4k rpm just sputters. After that time it gets slowly better and allows more rpm. If I cut it off and restart and give it wot as soon as it starts it goes to 7k rpm but then slowly sputters back down to around 4k sometimes 5k. So far I've done the following. New plugs, cleaned and adj the raves, cleaned and inspected the carbs, all new fuel lines, cleaned fuel selector, new voltage regulator. Any other suggestions I'm about ready to sell it!
Welch plugs, they are the welded caps on the head pipe. They rot out, typically the ones on the underside of the pipe, they hold the water. You'll need to have a new one made at a shop and have it welded on. DO NOT use JB WELD as a permanent fix, If you look close I left a small amount of the epoxy on it so you can see how NOT to fix it.
Here's a rotted one
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1995hx
New Member
Welch plugs, they are the welded caps on the head pipe. They rot out, typically the ones on the underside of the pipe, they hold the water. You'll need to have a new one made at a shop and have it welded on. DO NOT use JB WELD as a permanent fix, If you look close I left a small amount of the epoxy on it so you can see how NOT to fix it.
Here's a rotted one
What he said also ride it with the seat off you may be surprised!!!!!
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Ok I hooked water to my ski and ran it for awhile and my exhaust doesn't have any leaks but there was water coming from my water regulator so I took it apart and was dirty but the bellows didn't have any cracks so I cleaned and put it back on. Im wondering if I got a bad voltage regulator? What kinda voltage should I see at idle? I'm gonna bring my meter home tomm from work.
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