97 gsx no compression in front cylinder

[kingbrad89]

Long story short... I thought the ski (97 gsx 787) was having tempo fuel line problems. It had no power and was quitting on me. I cleaned the carb filters and changed all the lines, cleaned the selector valve, brand new plugs, and ran sea foam through it today. It ran awesome for about 10 mins then started running like crap again and shut down. I towed it back to the dock and trailered it. Wouldn't run at that point. I pulled the plugs and it looks like somebody held a blowtorch to the front cylinder's plug. Mind you it was a brand new plug. Checked compression and the front cylinder doesn't even move the gauge. Back cylinder shows 150 psi and that plug looks good. Is it possible that one cylinder only was starved for oil? Or am I missing something here. Sounds like I'm gonna be doing a top end. It's just weird that it shows absolutely nothing on the gauge, doesn't even move the needle. And it's only one cylinder. I'm going to do a oil block off kit and pre mix gas from now on. I checked compression when I initially started having problems with it running and i was at 148 in the rear and 150 in the front. Now 150 in the rear and 0 in the front. There's also yellow oil foam in the bottom of the hull but all the lines are attached... Somehow it must have starved for oil and crapped out that cylinder. Sound right? I haven't actually pulled the rave valves out yet, a few days ago I pulled the caps and they were moving freely. If one is messed up can it screw with compression readings? Also, should I plan on doing pistons and rings or just rings? On a tight budget

 

[Dr Honda]

OK... where to start.....

1) until you open the engine, I can't tell you why the engine died. SO... don't jump to any conclusions.

2) If you are showing 0 PSI in the PTO jug... then you are going to need pistons too. (at the minumum)

3) Knowing that you are at 0 psi... I would say the failure was from:
...a) Crank seal leak
...b) RAVE valve broke, and dropped into the engine
...c) Your damage was started by the Tempo fuel lines, and it gave up after power was restored.
...d) The seafoam cooked your piston since it washes oil away.
...e) The PTO carb was still plugged up.

4) since one of the issues could be a crank seal leak... I would be thinkgin about a full rebuild. IF, that is the issue, it will take out your new top-end.

5) with 0 PSI... it's very unlikely that it was an oil related failure... BUT... did you service the oil system lately?

6) You mention "Yellow oil" under the engine. What kind of oil are you using? The 800 engine needs a full Synth API-TC oil. Most of them are going to dark brown. If you had an oil issue, it could be, because you have the wrong oil in it.


Once you get the top end apart... post a pic of the damage, and we will help diagnose the failure.

 

[kingbrad89]

I use xps full synth, always have. No point in being cheap and taking chances with something so important. I had a truck to fix today so I'm most likely going to tear into it on Saturday. I thought the same thing when I saw the yellow oil, knowing that the oil is a greenish color and not yellow or brown. That's why I didn't understand the yellow. But, it is oil, no doubt, and there's no other fluids that it could be... A 2 stroke is as simple as it gets really... Its foamy, kinda seems like it got mixed with water and air. I have had this ski for 3 years with no problems till now. Always just did general maintenance and inspections. It was so sudden when it started acting up. I would hate to put a new top end in and fry it also. I figured I'd be safe if I did the top end and oil block off kit and ran pre mix. Can you inform me about the crank seal issues? I've never had one of these engines apart to see what they're all about. They seem simple enough though shouldn't be a problem. Thanks for the help and reply I appreciate it.

 

[Dr Honda]

Crank seals are critical to any 2-stroke. If the lower half isn't air tight... then you coudl go lean.

Also... did you get any "Bangs" out of the engine when it stopped? In the 800, there is some oil in the counter weight gears. If the case broke... that oil could have come out.

 

[kingbrad89]

Nope no bangs. When it quit on me I could tell something in the engine wasn't right. You could just hear that it lost lubrication. No clanks or bangs and it didn't seize but you could tell at the point of failure that that piston was metal to metal. It want even really a grinding sound or even a metal sound... Just didnt sound right and then almost immediately bogged and died

 

[kingbrad89]

The pics speak for themselves. What do i do???

 

[Dr Honda]

Wellllll....................

Looks like that jug went lean, and you melted the piston crown. That allowed the ring to break free, and cause the damage. Also, the melted aluminum is what caused the scuffing on the skirt.

I would personally do a full rebuild. If that's the original engine... there is no reason to try to save the crank.

 

[kingbrad89]

Any idea what cost of rebuild im looking at? Why do you think just that jug went lean?? Its a shame because the ski itself is very nice and in great shape. All new hydroturf and seat cover and everything. I would love to fix it but i cant be spending $1,000 on it. What do you think i could get out of it the way it sits?

 

[wslute]

well you could pull the motor, split the case clean and inspect crank bearings and get fulll engine seal kit with a new top end. prollly looking at about $500 maybe less.