Flywheel

[ford man]

quick question for anyone who can answer. i have a 2000 seadoo gs 718cc. ive been having to run on reserve. but now it wont start turns over and cranks just wont start sounds like its not getting fuel yada yada long story....... that wasnt my question my question is if the flywheel turns freely with the spark plugs out (clockwise)does this mean the motor isnt locked up? i am eventually going to compression check it and rebuild carbs and new fuel lines and selector switch. i know ive been running lean but im pretty sure the engine isnt siezed just wondering if that is true or what does it mean if the flywheel doesnt spin freely by hand (mine does im just curious ) thanks cody.

 

[Dr Honda]

If you can turn it, with the plugs out... then it's not seized. BUT... if you know it's been running lean... then you could have still melted the engine.


Unlike your car engine... fuel is the life blood of a 2-stroke. The fuel is how you transport oil into it. SO... if it's lean... not only does it run hot... but there is a lack of oil.

So... if it's still alive... then do all the stuff you know that needs attention.

 

[ford man]

Hi and thanks Dr Honda. yes i will do compression readings and go from there. i could see the heads when i turned it by hand (just peeking through the plug holes) by melted do you mean a head would be stuck? or just the whole block itself?
-cody

 

[mike_dmt]

I think what he means is you melted it in the sense that it doesn't have enough compression to run. Check that first.

 

[ford man]

okay i will thanks, if so what could it be a top end perhaps? sorry probably an obvious question but im fairly new to workin on these
-thanks cody

 

[LouDoo]

Cody,

Just get us some numbers and we'll go from there. There's no use speculating until we get a general idea of what kind of shape the motor is in.

Lou

 

[ford man]

i got compression readings from the time i cranked on it till the time it actually Started(first time its started!! font cylinder was 119 and rear cylinder was 121 im pretty sure these are good. although, i did see some white smoke coming out of the cylinders when i took the compression tester off? is this normal? i assume this is just gas vapors exhausting at an extra area besides the exhaust itself since the plugs didnt have the plugs in them? some people would say its low. but ive heard as long as their within 5 #s of eachother thats good? so i then put both plugs back in after grounding each one for the check and it started again. idled good. im still going to look towards replacing the grey lines selector switch and carbs(before going to the lake).
thanks everyone for the help i appreciate everyone please let me know what you guys think about the readings and the white smoke thanks cody i will add that i left one plug in the opposite side that was being tested i didnt think i was supposed to remove both plugs at same time was i?

 

[Dr Honda]

It's low. Once it gets down to that level... it doesn't mater if there is a spread or not.

The engine is done, and needs a rebuild.


Also... I deleted your other post.

 

[ford man]

even if its still running its done? or perhaps not having both plugs out when cranking on it would make a difference? not trying to question you i am just wondering. ( I only had one plug out at a time.)
cody.

 

[mike_dmt]

It might run out of the water, and maybe it will once its in the water, but probably not well, or for long.


You could try to re-test with both plugs out and the throttle pinned, but I couldn't say that will make enough of a difference.

You could do the top end, but guys will tell you the bottom will most likely fail right behind it.

Check SBT or a similar rebuilder for an engine.

You could hit up Minnetonka4me, or a couple other guys on this board for a good used one.

 

[LouDoo]

It may run on the trailer, it probably won't run in the water, and even if it does it won't run well. Your best bet is to get a reman engine, I would recommend a SBT premium engine.

You will still need to rebuild your fuel delivery system.

Lou

 

[mike_dmt]

Lou, stop reading my mind..... Or maybe it's the other way around...lol

 

[Jetskigoodies]

Next time you do a compression check, put the plugs boots on the ground posts.

 

[ford man]

okay i appreciate it . i wasnt holding the throttle wide open during the test only about a quarter i forgot to mention that.
thanks

 

[LouDoo]

I don't think it will make a significant difference but do another compression test. This time move the fuel valve to off, remove the spark plug wires and ground them on the posts, remove both spark plugs, test at full throttle.

Lou

 

[ford man]

okay i will try that thanks

 

[ford man]

perhaps it couldve been a faulty gauge im not sure i used a rent a tool from a local parts store (autozone) i may run by ORieliys(another local parts store) tomorrow and rent another one to double check . i was testing it cold and didnt have the throttle wide open (about a quarter throttle) the engine is all stock (13yrs old im not sure how many hrs as the GS model doesnt have an hr gauge. but ive put about 100 hrs on it myself in 4 yrs maybe a few more than that. can the engine still be good with low readings as such on an older motor like this? (i also kept one plug in as i did the opposite cylinder. ill remove both and ground them out. also i didnt screw the plug hole peice on the tester all the way in because i figured itd need to be gapped a litttle(i left it about 1 1/2 cranks out) since i borrowed it from a car parts store.figured itd be a longer piece than a seadoo cylinder kinda dumb i know but im not to famiiar with workin on any kind of engine.
-cody

 

[Dr Honda]

Take out both plugs... open the throttle... cold engine... crank for peak pressure. (don't put any extra oil into the engine)

But as Lou was saying... unless the gauge was REALLY out of whack... the numbers seen are too low, to change much by opening the throttle.

Basically... as the rigs wear (from heat, lack of oil, or time) and you loose compression... the combustion gasses will push past the rings, while running. That will displace the Air/Fuel coming in... and it will overheat the pistons. You are at a point where it's not going to run, once you put a load on it. AND... if you do get it to run OK... it will quickly eat itself.

 

[RUn2it]

The white smoke only means something if you are an Indian (casino kind) it means dinner is ready, get your booty back to the teepee pronto. If you're not an Indian it means listen to these guys, no magic wands or crystal balls will help and you may ruin a rebuildable core if you keep running an engine ready for hospice.

 

[mike_dmt]

If you left the gauge unscrewed 1 1/2 turns, you might have gotten a false reading. Cross your fingers, and test again as per Doc's instructions.

 

[ford man]

i got more readings this time reading was 128 on front and 135 rear. (im pretty sure i was misreading the gauge)

 

[LouDoo]

Well, that's just O.K., I would keep an eye on the compression, you will probably need to rebuild the engine in the off season. So for now all you need to do is replace the fuel lines and clean the fuel delivery system.

Lou

 

[ford man]

alright, i appreciate all the help everyone. Lou, perhaps would just a "top end" job do the trick for now? or would you recomend the complete rebuild. also is that still not normal readings for a 13 yr old motor? thats never been modded or anything. just curious if different 2 strokes can run good with lower readings as such also another ? do you think the fuel system rebuild(whtich i am doing no matter what before another lake trip) but do you think new lines filters carb rebuild could in anyway boost the compression if its all gummed up? only asking because Dr Honda said the fuel air mix? -thanks cody.

 

[LouDoo]

You can do what you want, it's your money your ski. And yes if all you want to do is improve the compression a new top end will do the trick. However I think you will find the bottom end won't last long and you'll be doing a complete rebuild. It's hard to say what normal compression is for a 13 year old ski, I've got a 96GTI, same motor (original) with compression readings of 146 and 147.

There's no magic formula that will improve your compression.

Lou

 

[ford man]

alright, i appreciate it. do you know about how much itd cost to have one rebuilt?