very sluggish start but plains out and runs good

[Doggtown31LCC]

i bought a 97 Seadoo GS (2 seater, 85hp, 770cc engine) last year, it's been running pretty good until the other day it wouldn't take off like it should and there was kind of high pitched knocking sound until it plained out and gets up to full speed, then it ran fine until you stopped or slowed down again. somebody told me to check where the water goes into the prop underneath, but it looks clean but i didn't take anything apart though. i don't really know very much about these things. i guess i'm gonna need to if i'm gonna have one this old.

 

[derek]

the pump comes out the back real easy on this year. there is probly something hung up in there. 2 10 mil wrenches, a 13 mm socket and a 17 mm socket and some longish extensions. you don't have to do anything with hoses from the inside.

 

[Doggtown31LCC]

thanks

thanks, i'll check that out

 

[Doggtown31LCC]

took out impeller

i took out the impeller and inpected didn't find, i guess i'll put it back together and try it out again, i think maybe it's just worn out? anybody got anymore suggestions.

 

[derek]

how do the bearings feel when you turn the pump? how much front-to-back play when you push on impeller?

 

[Doggtown31LCC]

good

it didn't feel like it had any slack in it at all. a guy i work with said he had the same problem with theirs except it's like a 2006 model and he took it to the shop and their replacing the impellor and the brass ring around it. i think it's costing him about $600. ouch.

 

[derek]

what is part number on impeller?

 

[Goddo]

I have the exact same issue with my 95 GTX. When the seadoo is at a stand still and you hit the throttle, the engine revs, the impeller turns, but it takes a few seconds for the seadoo to plain out, and then she takes off.

It's almost like she is trimmed to high. If you turn to the right, take off improves, but turning to the right improves the flow through the system anyway.

I just had the wear ring replaced at my dealer (whole other story) and the take off didn't improve at all. I gained about 2 mph on the top end, but the launch is still terrible. I can't even tow my kids around in a tube because she won't plain out with a load tied to her.

HELP?

 

[derek]

the impeller might be too long a pitch. like from a 787 motor. i put a 580 in my 97 GTI. (100 lbs heavier than a 95) beat wear ring. and it still jumped right out of the hole. 30 seconds later i blew the rotary valve gear, but that is another story. i have the 720 back in it now. can you read the part number on the impeller? you have to remove the pump and it is still hard.

 

[Goddo]

I actually have to pull the pump again this weekend. The dealers tech forgot to loosen the clamp on the main water inlet hose and broke the plastic fitting that screws into the impeller housing. They said you can just screw in a new fitting and are sending me one rather than me drive 3 hours again. I'm crossing my fingers on that one.

But I will look into your suggestion about a wrong sized impeller...I'll double check the part number while I struggle to get the broken nozzle out of the housing.:ack:

 

[derek]

shouldn't have even had to mess with water hoses. is there a big black plastic square on the back of the hull that the pump mounts to, or does the pump bolt straight to white fiberglass?

 

[Goddo]

Not sure, I've never taken it off myself but I have the manual...

Take a look at this diagram. (lower left corner)

The part that he broke is the little spout that fits into the impeller housing.(below loctite 592). The water is forced in through there to cool the engine. Last run I had a boat full of water and a hot engine in about 6 seconds.

It clearly states in the manual to disconnect both bailer pick-up tubes and main water inlet hose.

Am I going to need to replace the jet pump oil again?

 

[Goddo]

I've been doing more reading and I'm starting to think you may be right.

Before I got the seadoo, the previous owners had the impeller changed. I'm guessing that the shop likely used a less aggressive pitch than required.


Definitely going to look at the part number and compare. Thanks for the suggestion. As someone else alluded to in another post, this is an excellent site.

 

[Goddo]

Had the pump off tonight and fixed the water inlet. Seadoo is worse then ever off the start. She's pumping water like mad, but barely moving until she planes out. Once she does plane out, there is plenty of power.

I wasn't able to see the part number on the impeller because I didn't take it out of the housing, but I'm thinking your suggestion of the wrong impeller has to be right.

She is pushing water like mad, but just isn't able to move the vessel until she planes out.

Any other ideas ?

 

[Doggtown31LCC]

don't know

i don't think its the wrong size because it ran fine for all of last summer and all this summer till now, it just started doing it all of the sudden. i'll prolly just ride it out the rest of the summer then take it to the shop after the summer. but thanks for the help it was much appreciated.

 

[cordatta]

i had the same problem on my 97gts. there is a neoprene seal between the hull and the jet pump, also seal all the fittings coming off the pump at the hull. I know you said the wear ring was just replaced but when you have it apart check for saw tooth impeller blades and grooves in the ring. if you have those smooth the blade edges and replace the ring.

After I did all of this I noticed immediate response out of the hole and better top speed.

 

[Goddo]

i had the same problem on my 97gts. there is a neoprene seal between the hull and the jet pump, also seal all the fittings coming off the pump at the hull. I know you said the wear ring was just replaced but when you have it apart check for saw tooth impeller blades and grooves in the ring. if you have those smooth the blade edges and replace the ring.

After I did all of this I noticed immediate response out of the hole and better top speed.

Great suggestions, and just in time. I almost purchased a replacement impeller on ebay. Come to think of it, I don't recall even seeing the neorprene ring when I took the pump off...That could definitely be my problem. I also do have some light scratching on the new wear ring. I'll have the impeller touched up and get the ring and see how that works out. Thanks again.

 

[cordatta]

i know when i replaced my jet pump, venturi/nozzle assembly with an aluminum unit that had a stainless prop, new wear ring i put the new seal on there and it runs like a pissed ape. however i think the front seal on my pump is bad b/c after two outings the pump is leaking fluid. time to rebuild it i suppose.

 

[Goddo]

i know when i replaced my jet pump, venturi/nozzle assembly with an aluminum unit that had a stainless prop, new wear ring i put the new seal on there and it runs like a pissed ape. however i think the front seal on my pump is bad b/c after two outings the pump is leaking fluid. time to rebuild it i suppose.

Cordatta, you are the man....

It's exactly this type of information that makes this an excellent site. Thank you so much for sharing your knowledge. An $8 part and an hour totally changed my Sea-doo. I almost bought an impeller as I mentioned above.

My next step is to have my impeller freshened up at the end of the season.

***Note to anyone who is thinking of pulling their pump. Be careful of the main water inlet hose fitting. It is made of plastic and any up or down motion on the pump when pulling stresses the plastic and breaks it. The mechanic at a local dealer broke it, and then I broke it when pulling the pump. Luckily for me a friend of mine had a stainless fitting that was a direct replacement. :hurray:

I'm psyched about my Seadoo again. Maybe I won't be buying a new one afterall.

 

[cordatta]

just try to share what little things i have found out since beginning to work on mine. hopefully this weekend i will be able to get the pump rebuilt with all new internals to stop my oil leak. glad to see that it worked out for you with the new seal.