1997 seadoo gtx ******HELP ME *****

[stevemacd]

Hi
Im new to owning a pwc but i have owned many other toys and have done work on them. This seadoo was bought roughly 3 weeks ago and was water tested before i bought it with great results, but when i went to use it the next day it would not start. after a few min of playing around i got it going and was able to keep it running. It is running great but getting it going is a task in its self. as the day went on it got worse and worse to the point that i pulled it out of the water because i didn't want to keep messing around to get it running. later that week i pulled out both carbs and replace all the gaskets and the little in carb fuel filters. once i got it all put back in it ran great and only need you to push the starter button for a split second to start (this was out of water with a hose attached). the next weekend that i took it out to lake simcoe and it started great the first time, once i got to the beach i shut it off. when i went to take it out i have to give it a little gas to get it going this went on all day and now im here trying to see if there is anything else i could try to get this fixed.
So far i have:
rebuild carbs both (plt and mag)
replace almost all fuel lines to new black ones
cleaned main fuel filter and selector switch
tested spark and its great
tested compression ( 130psi dead on in both cylinders)
changed spark plugs
cleaned RAVE valves

Does anyone have any ideas on what could be causing me to need to push the gas to start this. Any ideas would be great i would like to take it away this weekend but dont want to pay the local shops 100$/hour labor charge.
Thanks in advanced

 

[Dr Honda]

You need to replace all the fuel lines. The old Tempo fuel lines will just continue to send "Goo" into the carbs, and plug them. So.. change them all, and open the carbs again. (The vent isn't a big deal)

also... 130 psi... that engine is tired. It should be around 150 PSI. So... that will make it hard to start. (and loose a lot of speed up top) It's time for a top-end. If you continue to run that engine... you will get a melt down... and it will go from a top-end, to a full rebuild.

 

[stevemacd]

ok i will get on taking out the rest of the gray stuff. Really how much would it cost roughly to do a top end reb uild and is this something i should do myself because i have never done it before.

thanks for the fast reply

 

[Annihilator]

Hi, my '98 GTX has about the same cold compression but always starts right away. I would replace the rest of the lines and then go through the carbs again. It may take a few cleanings to get all the crap out.

 

[stevemacd]

thanks for the info annihilator. When doing a compression test should the ski be hot or cold ?

 

[Annihilator]

From what I'm told, if you do a compression test warm, you will get a more accurate reading, and it will be higher than cold.

 

[Dr Honda]

.....................and it will be higher than cold.

And that's why you do it on a cold engine. A warm engine... or oil in the cyl's will mask an issue.

So... the test is... cold engine, and open the throttle. Crank till you see max pressure.


Here's the deal....

The engine will continue to run as the compression drops. BUT... the compression dropping is telling you that there are bigger problems. As the rings wear... the hot combustion gasses get past them, and over-heat the piston skirts, cyl walls, and rings. This extra heat also is cooking the oil the is supposed to be protecting the pistons.

The second thing is... as the gasses get down into the lower half... it's displacing the air that is supposed to come in from the carbs. So... now you start running lean... making the over-heating issue worse. (this isn't engine over heating... this is internal temps)


So where does this lead us?? Well... right now, you have a good engine that needs a little love. SO... if you do a top end now... that engine could continue to run for the next 5 years without an issue. (or longer) But... if you ignore it... you WILL melt a piston. (Probably before the summer is over) Now, you need a full rebuild since the hot, melted aluminum has killed the crank, and rod bearings.



So it's up to you... but I recommend doing a top-end over a full rebuild.

 

[stevemacd]

Ok that was great i was not sure why i needed to do the top end but this makes logical sense. so at this point when im going to do a top end rebuild will i need to do anything to the jugs or can i just a ring and piston kit and pop that in provided that there is no scoring on the cylinder walls and head?
just for info reasons this ski has only 172 hours on it when i got it 3 weeks ago it had 169 on it.

 

[Rickbaro]

... 130 psi... that engine is tired. It should be around 150 PSI...

Does Sea-Doo publish this info? I didn't see it in my engine manual; it only talks about a displacement measurement.

Now I'm a little more worried about the 140 pound readings in my '05 717. Not really worried, but if there's a rebuild in my near-future, I'd like to start planning.

 

[Dr Honda]

Ok that was great i was not sure why i needed to do the top end but this makes logical sense. so at this point when im going to do a top end rebuild will i need to do anything to the jugs or can i just a ring and piston kit and pop that in provided that there is no scoring on the cylinder walls and head?
just for info reasons this ski has only 172 hours on it when i got it 3 weeks ago it had 169 on it.

You have to pop the head off ad take a look. If it's not too warn... you could get away with a quick hone, and new rings. If there are gouges... it will be a bore and new pistons.

Does Sea-Doo publish this info? I didn't see it in my engine manual; it only talks about a displacement measurement.

Now I'm a little more worried about the 140 pound readings in my '05 717. Not really worried, but if there's a rebuild in my near-future, I'd like to start planning.

If you are above 140... you are fine. 150 is our cold target... but a fresh rebuild can be 145 to 155 PSI. It just depends where the squash band got set too.

There are a few of the manuals that spec 150 psi on the compression test... but they don't give a low spec. Generally... I say 135 on a seadoo engine (800 or smaller) and it's time for a rebuild. at 135... the engine is still running... and a quick top-end, or even a set of rings will help keep the engine healty for a long time. If you let it get down to 120 or lower... the bottom half will have been cooked, and probably isn't worth trying to save.

I see it all the time here. Guys will have very low compression, or have an actual melt-down, and try to do just a top-end. Well... when they do... the new found power normally just kills the crank or rod bearings... and the engine scatters. (and the money is wasted)


This is what happens when you put a top-end on a roasted crank.

 

[riding high]

Ok that was great i was not sure why i needed to do the top end but this makes logical sense. so at this point when im going to do a top end rebuild will i need to do anything to the jugs or can i just a ring and piston kit and pop that in provided that there is no scoring on the cylinder walls and head?
just for info reasons this ski has only 172 hours on it when i got it 3 weeks ago it had 169 on it.

If I were you I would tear it down, do a visual inspection, mic the cylinders and go from there. If there is any wear in the jugs at all I would have them redone. It would be a lot easier now while it's torn down than to have to go to all the work to tear it down again. Fullboreonline does some great work at a pretty reasonable price.

 

[stevemacd]

i just finished replacing all the tempo lines and new clamps. Tonight i will pull the heads on and post pictures of what i find.
What are the chances that i will be able to use it this weekend? if it means risking my motor i will just cancel.

Also just wanted to add when the seadoo is out of the water and hooked up to a hose it starts perfectly no hesitation and no need to use gas just a quick tap of the starter button. Is this caused by the extra load on the impeller ?

 

[riding high]

i just finished replacing all the tempo lines and new clamps. Tonight i will pull the heads on and post pictures of what i find.
What are the chances that i will be able to use it this weekend? if it means risking my motor i will just cancel.

Also just wanted to add when the seadoo is out of the water and hooked up to a hose it starts perfectly no hesitation and no need to use gas just a quick tap of the starter button. Is this caused by the extra load on the impeller ?

Don't get in a hurry. Take your time and make sure you check and double check everything. Operating the unit in the water is a completely different enviornment than out of the water. If you have checked everythng else you might want to set the carb adjustment just a little richer. turn the adjusters in small increments.:thumbsup:

 

[stevemacd]

haha ok i will wait and see how things go. i will post pictures tonight when i pull the heads off the ski. I know there are o rings on the head but do i need anything else for gaskets. If so what do you guys recommend?

 

[stevemacd]

THE HEADS ARE OFF AND HERE ARE THE PICTURES :thumbsup:
www.photobucket.com/seadoo97gtx

i tried to upload them to my profile but my pictures were too big and i didn't want to loose quality.

 

[Dr Honda]

As above... you are a little on the lean side... but that's probably because you were plugged up with Tempo hose goo.

No... if the rubber is still soft... you don't need anything to put the head back on.

The pictures don't look bad... but there is wear... and I think I'm seeing rust. (not good) If that was my engine... I would measure the bore, and see where you are at. If it's at 0.001" or less wear... it's a hone, and rings. If it's over that... I would do a full top-end.

 

[stevemacd]

so this may be a stupid question but i have never worked on oil injection before but if my fuel is a little lean so the amount of oil getting into the cylinder follow or is it adjusted on its own?
and if its a bit lean shouldn't there be a little less black on the piston ?
also yea there is a tiny bit of orange but everything is smooth there is no bumps or ridges.

I guess i will have to drag the ski to a local shop because i don't have bore gauges and im not sure that i will ever really use them again correct me if im wrong. Or is there a way i can do this without the proper tools?

 

[stevemacd]

HAHA what a joke i went to the only local seadoo shop and asked if they could measure my bore and the guy at the desk told me it would be a 3 day job and roughly 90$. Is that seriously what this cost to get done ? I didnt want to buy the tools to do this but i guess i might

 

[mikidymac]

That is not a good shop and they are blowing smoke. If you take your two cylinders in it should only take about 5-10 minutes to check so they should only charge about $7 if their shop rate is $70 per hour. Any engine machine shop will be able to check your pistond and cylinder, it does not have to be a seadoo shop. I will second fullbore online. They are great. $450 for all top end machining and parts.

 

[stevemacd]

yea they seem to be jokers in there they told me 125 for two carb rebuild kits. just crazy !
so i looked to a local machine shop and the guy was very helpful he said bring in your cylinders and pistons and he will do it for nothing so im going to pull the pistons off and the cylinders and take them in.

 

[mikidymac]

If this is the origional top end be very careful because some use loose piston pin needle bearings and if you loose them in the crankcase it will have to be split. Put rags tightly into the crankcase so if they fall when you remove the pin they will not fall in.

 

[riding high]

:agree:WATCH THE NEEDLE BEARINGS IF YOU HAVE THEM. They are uncaged and will go everywhere. Check your owners manual and see how many there are in your engine. I believe there are 34 per cylinder. Plug everything and then wrap something right below the piston to catch the bearings, then take them to a clean area and count them. You must account for all the bearings. I actually had a large magnet that I laid directly below the piston to help catch the bearings.:willy_nilly:

 

[stevemacd]

So i have been looking online for a video to make sure i know what this is all going to look like once i get in there but i cant find anything. Im guessing once i remove on of the circlip i can use a small socket to tap the wrist pin out? once this is done the piston head should come off if im not mistaken and then will all the needle bearings fall out or will they stay in the piston rod ?
Im a little nervous about doing this, but im hoping it wont be as hard as i think.

 

[riding high]

So i have been looking online for a video to make sure i know what this is all going to look like once i get in there but i cant find anything. Im guessing once i remove on of the circlip i can use a small socket to tap the wrist pin out? once this is done the piston head should come off if im not mistaken and then will all the needle bearings fall out or will they stay in the piston rod ?
Im a little nervous about doing this, but im hoping it wont be as hard as i think.

I can only tell you from my limited experience that the chances of them staying in the rod are slim and none. SeaDoo actually made a special tool/cover to slip under the pistons to aid in catching the bearings. I took all the precautions I could and still ended up one bearing short. It took the wife and I two days to find the silly thing. They do have caps on each side of the rod to keep them in place. I guess if you hit it just right you might be fortunate enough that they would stay in the rod. I would prepare for the worse case and then anything short of that is good. Don't forget it has to go back together.:thumbsup:

 

[stevemacd]

lol ok i will wait untill the weekend that way i have the whole day to work on this project.
I will try and take video of this for the sake of the forum that way the next guy will know how its all coming apart. :cheers: