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Discussion Starter · #1 ·
97 MACH Z WITH 2100 ORIGINAL MILES SLED IS FOULING PLUGS LEFT & RIGHT WENT THROUGH 2 BOX'S OF NGK 3194 BR9ES SOLD TOP'S SO FAR!
BACK FIRES I HAVE READ EVERY TOPIC I CAN FIND ON 4 DIFRENT WEB SITES WITH SIMALAR PROBLEM'S THAT I AM HAVING. I HAVE HAD THE CARBS CLEANED AND GONE THROGH AND JUST GOT DONE PUTTING A $130.00 STATOR IN IT TO NITE AND STILL IS NOT RIGHT. I'VE READ ABOUT A WIRE SHORTING OUT UNDER THE ENGINE OR THE BULK HEAD ? I THOUGHT MOST ALL THE MACH Z PROBLEMS WERE WITH THE 98 MACH Z'S. I'M LOST . I HATE TO SPEND ANOTHER $350 ON A CDI BOX AND STILL RUN THE SAME . I'M ABOUT READY TO POUR GAS ALL OVER HER AND THROW A MATCH TO HER! ANY IDEA'S ? :cussing: PLEASE SOMEBODY POINT ME IN THE RIGHT DIRECTION
 

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Is the plug fouling problem on one specific cylinder or all of them? Is the motor stock or modified? If it has ever been moded in any way then trouble shooting without being there is much more difficult. Is the fouling at an idle or while running, if it is running at what average rpm is there a problem? Are you the original owner, if so is this a new problem or one that has been evident since the machine was new?
Make sure the basics are covered. Is the motor in sound mechanical condition y/n. Is the fuel present,clean and of the right grade? Is the fuel being delivered at the proper ratio to air (are the carbs adjusted and woorking properly). Is there compression and is it high enough for the combustion process to happen. Is there spark y/n? Is the spark at the right time y/n?
Hopefully you have answered your own question with what you said in your question. I would suggest not going into the expensive electrical parts any further till you have done some gremlin chasing. Internal elctrical parts are pretty hearty and do not fail very often, replace them only as a last resort. If the problem is intermitent, shows up every once and a while then goes away, but causes a constant backfire then you might be looking at a short in the wire harness. The only way to trace this down is to look for a wire rubbing on metal somewhere or let the machine sit at an idle and simply wiggle the wire harness wherever you can touch it and see if the motor pops, if so inspect around that area. When the backfire is happening and how often it does will help trace down the source, try to include this info in your next post. One thing to check is if you are running the right heat range of plug. I am questioning the BR9ES plugs you mentioned. If you have any doubt double check with a dealer or shop who knows for sure. My quick reference book is showing all the ski-doo triple cylinder sleds in 1996 using BR10ES plugs, you might be running the wrong heat range plug, if the heat range is too cold you will foul plugs all day. I know that triple cylinder sleds from ski-doo and polaris ran a different heat range plug fom the twin cylinder sleds. CHECK YOUR PLUG HEAT RANGE!!!
Check the plugs and see if it they are correct, change them if needed. Write back with some of the specific questions (intermitent, all or one cylinders, only when hot. etc). and we'll try to get more info to you. No promises but If the motor is solid hopefully this is a simple problem. I have only seen 4 or 5 bad stators out of a couple thousand sleds go through the shop, external coils are more common but far more simple to trace down. Good Luck and write back. :rolleyes:
 

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BR9es's are what you should be running. The br10es's were way too cold. Also 45 pilot jets help that problem a lot. In 97 they went to a fine threaded air screw. So make sure it is out 4 turns. If you have access to an infrared thermometer you can check the pipe temp close to the cylinders and get it up to where it is burning the fuel instead of running rich at lower rpms. Also it'e a good way to make sure you have them synced good. A rich blubbery motor will have a pipe temp of about 180 or 190 at idle. It'll be about 350 when the low speed stuff is straightened out. They jsut can't burn all that fuel even though at low speeds. Those are not egt readings but outside pipe readings just behind the weld on the pipe.
 

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Discussion Starter · #4 ·
Thanks guys my computer died a couple of days ago from a deadly virus,
anyhow the sled is bone stock with 2100 miles on her, has compression of 150
plus in all three cylinders with new plugs it will start good and then might drop a cylinder before it warms up. If not one trip around the yard and it will drop one or two.& plugs are very wet looking . I was wondering if I NEED TO WARM THIS SLED UP MORE LIKE taking it off of full & half choke as soon as I can and let her just sit there and idle for a while and let her warm up? I did get about 50 miles one day WITHOUT A PROBLEM , BUT THE REST IVE HAD NOTHING BUT PROBLEMS and have only put aBOUT 160 MILES ON IT TOTAL.CARBS ARE STOCK factory jetting AND CLEANED, the guy i bought it from said he summerized the sled really good , I wonder if he over fogged it and put toooo! much stabil in the tank , some of the miles I put on at first went ok with a back fire at about mid throtle, then there would go another plug again ,HOPE THIS ADDS TO MORE OFF AN IDEA OF WHAT IS WRONG WHAT DOYOU THINK ?
 

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Go to sled store, buy three NGK BR9EYA spark plugs. Gap them to 0.018 inches. Then it should be fine. I have a 1997 Mach 1, it's jetted with 45 pilots, 340 main jets, every thing else stock. Running BR9ES plugs for a couple hundred miles, start it up next time, at least 1 will be fouled out. Backfires, runs like crap.

Put in the BR9EYA plugs, and start it up, let it sit until it warms up, runs perfectly. Plug color perfect, piston wash perfect. I can't get them to foul out.

Ski-doo released a service bulletin in 1998 saying to run BR9ES plugs at 0.018" gap in all triples, regardless of what's listed in the specs.

Been running BR9EYA plugs for 4 years. I also e-mailed NGK about the BR9EYA plugs because someone said it's half a heat range hotter than the BR9ES, and it has a longer reach. The guy from NGK said it is the EXACT same plug as the normal BR9ES, but has the groove in it to help with sleds that foul plugs. He said that I can use the BR9ES, BR9EV, BR9EYA, and BR9EIX plugs in my sled. Any plug with the "9" in it is exactly the same heat range. The only difference is the firing end materials and shapes.

I bought a set of the EIX's to try out, but probably won't get the chance for a couple years. I normally get a season or two out of a set of plugs (1000-1500 miles per year).

Hope this helps.

Jim
 

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Boy is this post bringing back memories.............................
Go get some Iridium spark plugs, either Denso or NGK. My mach did the exact same thing until I installed a set of the Denso's and she went about 1500 miles and never fouled again.
 

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you might want to check to see if the arm for the oil pump is not sticking open that was a problem with the mach1 & machz of that year.to check this you should take your canaster out and look at it there are two lines one on the pump one on the arm they should line up at idle I bet that is the problem
 

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Discussion Starter · #10 ·
THANKS FOR THE HELP, A GOOD FRIEND IS GOING OVER HER AND FIND OUT WHATS UP. HE ALSO T0LD ME ABOUT THE PLUG AND THE OIL PUMP SPRING PROBLEM , HE'S AWSOME WITH SKI-DOO'S OR WHAT EVER HE'S MESSING WITH.
WILL LET YOU ALL KNOW WHAT HE FIND'S OUT.
 

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97 MACH Z WITH 2100 ORIGINAL MILES SLED IS FOULING PLUGS LEFT & RIGHT WENT THROUGH 2 BOX'S OF NGK 3194 BR9ES SOLD TOP'S SO FAR!
BACK FIRES I HAVE READ EVERY TOPIC I CAN FIND ON 4 DIFRENT WEB SITES WITH SIMALAR PROBLEM'S THAT I AM HAVING. I HAVE HAD THE CARBS CLEANED AND GONE THROGH AND JUST GOT DONE PUTTING A $130.00 STATOR IN IT TO NITE AND STILL IS NOT RIGHT. I'VE READ ABOUT A WIRE SHORTING OUT UNDER THE ENGINE OR THE BULK HEAD ? I THOUGHT MOST ALL THE MACH Z PROBLEMS WERE WITH THE 98 MACH Z'S. I'M LOST . I HATE TO SPEND ANOTHER $350 ON A CDI BOX AND STILL RUN THE SAME . I'M ABOUT READY TO POUR GAS ALL OVER HER AND THROW A MATCH TO HER! ANY IDEA'S ? :cussing: PLEASE SOMEBODY POINT ME IN THE RIGHT DIRECTION
 
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