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ZRT 600 engine burndown...

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ZRT 600 engine burndown...

Postby Rodeo4Wheeler » January 21st, 2002, 1:03 am

Hello everyone, I am new to this forum. I read the posts about the SkiDoo triple/triple problems and was impressed with the info some of you had! I'm hoping to get some help of my own here.

My dads '97 ZRT 600 has been sitting for over a year now. We were riding around New Years weekend last year, and he had his engine burn down. The snow was mushy, about 3 inches on the trail and very loose from all the sleds. The temp was around 28 deg. We were cruising at around 75 mph and he hit it for about 7 seconds. He said he got just about 95 mph and had let off on the throttle and his tach dropped and sled stalled. He got the hood up and tried to pull it over slowly, engine was locked tight. Had to tow him with my MXZ for 3 miles to the trailhead. :(

Got it to my friends shop, he owns a SkiDoo dealership. He started looking at it and said, "I think you either got water in the gas or ran very lean." He attemped to pull the wrist pin with his SkiDoo tool, but no go. The bearing is seized pretty bad. The Cat dealers around us are total idiots, nothing against Cat but I'd NEVER take my sled to these guys.

The clutch side piston has a hole in the center the size of a quarter. Head has ring chunks impaled in it. Center and mag side look fine, heads are shiny and clean. What is the head supposed to look like when you pull it? Dark, clean, smoky, I don't know much about reading plugs and heads.

My dad and I are both very mechanical, we have rebuilt clutches and susp. systems. Is this something we could tackle? I want to have him going next fall when I get my new sled.

What should we look for as the cause? Water, lean jetting, oiling problem? So many things on a 2-stroke. The jets are as factory specs on clutch cover, we THOUGHT that was safe to use. Are Cats triples reliable? I seem to have talked to many happy ZRT 600 and 800 owners. Big problem seems to be running too rich from factory, but rather have that than fragged engine!

Well, I have rambled on long enough. Any help you could give would be greatly appreciated.

Thanks, and have a great winter!
Abraham in Michigan
No sled till next fall :(
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ZRT 600 engine burndown...

Postby straycat » January 21st, 2002, 3:13 am

Well, You could have a couple of diff. problems. FIRST, Did your dad leave gas in the carb while it sat? If he let gas sit in it while it was in storage for time, The main jet probably closed slightly and caused it to run lean. I have seen this happen more that once.
Water is possable but he should of had a problem early in the day since water settles on the bottom of the tank. He should have sucked that right away.
Another possability is that if your dad went from WOT to closed with out feathering the throtel down, he caused the oil injection to run lean. this is also a possability but not likely.
I would go with a gumed carb. prob. but with out acctualy seeing it I wouldn't beable to tell you. good luck hoped I helped
Till the speed overcomes the fear of death!

Long live the cat!
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ZRT 600 engine burndown...

Postby Rodeo4Wheeler » January 21st, 2002, 4:03 am

Okay, the sled was purchased in 2000. He pulled the carbs, soaked and cleaned them and replaced the fuel lines with new ones. Also bought new CDI boxes for the ignition. (They mount on the airbox) Also, the needles, seats, and jets were all brand new AC parts that fall. How do you prevent water from causing a massive failure? You can't know every time you get gas there won't be water in the gas.

Abraham in Michigan
No sled till next fall :(
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ZRT 600 engine burndown...

Postby michahicks » January 21st, 2002, 4:17 am

A 600 HAS to be running on all 3 cylinders to achieve the kinds of speeds you're talking about.
Water is pretty much out of the question,
assuming you have a fuel filter, as most won't let water through, and the ones that do would have let water into all 3 carbs. It was warm out,
so the machine should have been on the rich side with the factory jets. Best bets? In my book, the most likely would be a partially blocked main jet in the PTO carb, or a bad crank seal, again on the PTO side. Blown base gasket and carbs way out of sync are also possibilities, but not as likely.

Something caused that cylinder to run much hotter than the rest. Those are the things I'd check out first anyway.
AL
1997 38' HR Endeavor, 275 Cat, Freightliner
2003 CR-V Toad, Blue Ox, Ready Brake
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ZRT 600 engine burndown...

Postby Luv2sled » January 21st, 2002, 6:46 am

Regarding bad gas......I never buy gas at a low traffic gas station, only at the high traffic stations (the odds of getting bad gas are much less). When your a long way from home or on a trip in an unfamiliar area its hard to know where the "good" stations are. If you worried about getting bad gas you should probably buy a bottle of Isopropal (sp?) and add a small amount at each fill up....it eats the water up and works great.
Life is like a crap sandwich, the more bread you have the less crap you have to eat.
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ZRT 600 engine burndown...

Postby 4th ski-doo » January 21st, 2002, 7:02 am

I have heard of some 97 trips being left over 96 with bad oil pumps. Being other cyls in good shape my guess would be unbalanced clutch had wear on seal and PTO side meltdown. Get the clutch spun to find out if that had anything to do with it.If you just did the carbs and clutches back track for any errors. Sorry to hear problems and good luck.
MM7 wrote:
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ZRT 600 engine burndown...

Postby kop7888 » January 29th, 2002, 7:06 pm

i think i know the problem worked on sleds in dealership for 20 some years a lean condition will seaze the piston on the exhaust side this is the hotest point of the piston. a cold seizure will be at four corners a hole in the piston is from timing my best guess is wrong cdi box put back together whith new oem parts check timing as per service manual make sure you run eng for 5 min to get all eletronics heated up. ps make sure has the right NGK spark plugs hope i was of some help
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ZRT 600 engine burndown...

Postby GlennXC » January 30th, 2002, 2:16 am

regarding water in the gas, I almost always have a bottle of dry gas(Isopropyline) with me so I can add some everytime I put gas in. I have heard so, so many stories about seizing up from bad gas. I guess I'm a little paranoid. For the extra effort, you mine as well.
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ZRT 600 engine burndown...

Postby KneeDeepInSnow » January 30th, 2002, 2:19 am

isn't that the same thing as isypropal(sp?) alcohol?
what about thos int tank cartridge things that you put in???
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