Here are the symptoms, can you help with any answers? - Snowmobile Forum: Your #1 Snowmobile Forum

mwinters · 11-15-2009, 07:57 PM

Hello guys,

I'm new to the forum but have been sucking information from you as an unregistered member for quite some time. I have got much needed information from you guys and would love to hear what you think about this.

Here is my story...

I bought a 1999 ZR 700 for $400 dollars today which does NOT run. It has spark, and great compression, but will not start. Also, I feel like its alot of compression to pull for a 700, am I wrong? The previous owner said that last year, the sled began to start hard. When he got it started, he would make a few laps around the house before it would die. After it would die, he could never get it started again until it had time to sit for a day. After that, the cycle would repeat.

I asked him if he has done anything to fix these symptoms, but he claims he's "no mechanic". So I obviously would believe that its either a leak / vacuum restriction, a dirty carb i.e jets / floats, fuel pump, or maybe a restriction in the fuel tank. Could it be something else?

Today I pulled the fuel pump to check and see if that was the culprit considering it was rusted to hell. I blew on the inlet and it passed through, and when I sucked a vacuum in, it closed. Vice versa for the outlets, also the diaphragm looked fine, so I believe my fuel pump is o.k. However, when i pulled the outlet hoses off (hoses to the carbs) they seemed to be dry, and I had just pulled the engine over about 7 times. The fuel filter looks like it's original so I will replace it, but its before the fuel pump and the pump had gas in it when I pulled it off?!?

I'm gonna clean out all the fuel systems replacing all lines, replace fuel filter, check vent hoses, and clean the carbs. Hopefully this will solve it.

So based on what the previous owner said, what do you think?
Should I get a new fuel pump any way?
Where can I get a carb rebuild kit for the ZR?

ANY AND ALL INFORMATION WILL BE MUCH APPRECIATED!
AND I WILL KEEP YOU GUYS UPDATED!

Cheers,
Matthew

Mrdman2442 · 11-15-2009, 08:21 PM

Engine is hard to pull over and quits once warm, sounds like it could be siezing. What were the exact compression numbers?
Pull the fuel lines off the carb and spin the engine over, if fuel spurts out the pump is fine. Although crap floating in the tank could plug up the filter causing the carbs to run dry.

mwinters · 11-15-2009, 08:26 PM

Well it's not hard to pull over really, it just seemed harder than what I'm used to. As for the compression numbers, I used my thumb over the plug hole, but my compression kit is coming in so I will be able to post those numbers. As for the fuel pump test, duh, I should have thought of that!

By the way what is the compression tester adapter size for sleds, 12mm, 14mm?

Thanks again!

jamesu9165 · 11-15-2009, 08:27 PM

yeh my polaris 488 would start fine and idle all day but when you gave it any throttle it would run tight and after cooling it would start and run. the crank bearings where shot. when it ran tight out on a lake it was not fun so make sure u trust the sled before doing to much with it... its a pain in the ass tho to get down to the crank to see what condition the bearings are in but hopefully it is only a fuel starvation issue. i would just clean the pump rather than buying a new one.

mwinters · 11-15-2009, 08:31 PM

Well that's the thing, it wont start.
It takes tons and tons of pulls, or says the previous owner, I have never had it running.

When I went to buy it I was thinking the same thing, that these are symptoms of a bad crank.

I guess we will have to see when I get the fuel system and carbs cleaned out!

**BC_Dan** · 11-15-2009, 10:45 PM

I think you are heading down the right path, you have spark, and mechanically it seems to be ok. You can clean the carbs without a kit, most of the time you won't need to replace parts, only clean them. It's handy to have a couple of inlet needle/seats around in case you have an old type with a brass needle that has a groove worn in it...

I would consider getting a fuel pump rebuild kit, they are less than 10 bucks and will make your existing pump work like new. The pump is not complicated, just make sure you make some marks across the edge before you disassemble (some already have 'em) because it's easy to "clock" the pump so the outlets aren't pointed in the right direction. Take pics, that helps too.

It's pretty inexpensive to rule out fuel pump/fuel line/dirty carb issues, I like to start at cheap and work toward expensive

**kccats** · 11-16-2009, 06:02 AM

Clean the carbs, fuel pump and tank! Replace all the fuel lines including the pick up in the tank!

Arctic Addict · 11-16-2009, 09:08 AM

I'm curious, what was the condition of the spark plugs after you pulled the motor over a few times? (ie wet or dry) If the plugs are dry, then clean the carbs and pay a lot of attention to the pilot jets. Floss the pilot jets out with a single strand of telephone wire. New plugs never hurts along with new fuel line, filter and a pump rebuild.

mwinters · 11-18-2009, 02:08 PM

I did check the plugs after I pulled it over a few times to see if they were wet and getting fuel. It seemed however that one was a little wet, and the second was dry, with a little oil around it (old or new I don't know)

My compression tester should be here today so I'm gonna see what that is. Tomorrow I'm going to rebuild the fuel pump, and replace all the lines and filters. Also I'm going to clean the carbs.

Kccats: How do I go about cleaning the pick up in the tank?

Thanks!

mwinters · 11-18-2009, 02:39 PM

Hey guys, just took a compression test. 130psi in both cylinders!
Tomorrow I will replace the whole fuel system and see where I'm at then.

BIGTRUCKBALLIN4 · 11-18-2009, 02:41 PM

Theres a tank grommet(rubber)behind oil injector tank,remove injector tank and pull grommet out,make sure gas tank is pretty low to empty,gas everywhere not good.At least that should be the general procedure,never worked on a cat,but my poolaris is like that so you should get the idea.Follow main fuel line to the tank.

Arctic Addict · 11-18-2009, 04:53 PM

From your last posting (one wet plug one dry plug) my guess is that your pilot gets are gummed up. Take the carbs completely apart and soak the parts overnight in a bucket of good cleaner. Then reassemble once you are sure each part is clean. Pay alot of attention to the pilot jets to make sure they are not clogged. I floss them with telephone wire. You have good compression and you have spark-sounds like you just need fuel. Goodluck!!

BIGTRUCKBALLIN4 · 11-18-2009, 05:22 PM

Behind that grommet should be youre in tank filter(screen)you were talking about.

mwinters · 11-19-2009, 12:32 PM

UPDATE:

So I started pulling the ZR apart today and this is what I have found so far. When I removed the air box; one, the rubber booties folded over that the carbs slide into, making it very hard for them to get air. And two, the bottom of the air box had what looks like insulation or a nest blocking off any more air that could possibly make it to the carbs from the smooshed booties! THE CARBS WERE ALMOST 100% BLOCKED FROM GETTING AIR! Would this explain the hard starts? Then in combination with dirty carbs cause the engine shutdown?

The fuel lines are very old and brittle, one had a chunk taken out close to the nipple. The hose that came from the crank to the fuel pump also had chunks out of it with fraying going on. I also noticed on the fuel pump itself, one of the metal nipples has been kinked probably about 10% is this a problem? Airflow goes through it fine...

The carbs look very very dirty, I haven't cracked them open yet, but by looking at the throttle body and the intake side, it's very grungy.

As soon as the rebuild kit for my fuel pump is in, I'm gonna piece it back together with new lines, filters, cleaned carbs and unrestricted booties!

So Arctic Cat isn't cheap and just putting insulation in their boxes right? That was a nest right?!?

Thanks guys!
Matthew

**RJ Gleason** · 11-19-2009, 04:52 PM

You got it right!
Also replace the line inside the gas tank since the rest o f them are so bad.

mwinters · 11-19-2009, 05:23 PM

UPDATE 2:

So now I have 130psi compression, spark, all new lines and filters, rebuilt fuel pump, and unrestricted carbs. I know for a fact fuel is moving to the carbs, but this is what I have found.

One cylinder is not getting fuel, the other I think is restricted but getting some. The carb that wasn't getting fuel was a little rusty in the pick up, and the choke. The jets when I pulled them didn't have gunk in them, in fact they were pretty damn clean. The floats don't seem to be sticking, and the t valve that feeds fuel to both carbs in clear.

So I'm in the middle of cleaning and soaking, and then I'll update.
Do you guys think that the carb is the problem? I mean it has to be but it doesn't seem all that bad except the rust and residue in the pick-up of one of the them.

Thanks,
Matthew

**RJ Gleason** · 11-19-2009, 05:47 PM

That can be enough to keep it from working.

mwinters · 11-19-2009, 08:32 PM

UPDATE 3:

The carbs are clean as a whistle, put them back in and the same thing, not even close to starting. I pulled the plugs and the same cylinder is bone dry but, it has some fuel in the intake side where the carb slides in.

So I looked in to the intake and guess what I see, insulation sucked right down in from the little critters who made their home in there. So I assume that the previous owner obviously had a nest, sucked it down in, and just kept on trying to run it.

My question is now how bad is this going to be to clean out? Will it have made it down in the crank? Will just pulling the jugs be enough? Also can I reuse my head gasket or should I get a new one?

Getting closer guys!
Matthew

orin250 · 11-19-2009, 10:48 PM

i went through something similar with my 96 580 and it turned that a piece of the piston skirt broke off and the rod smashed it through the bottom of the case and when that happens it cannot get fuel into the cylinder because of the air leak. so for the half hour it takes to pull the motor out i would do it if i was you and have a peek a boo at the bottom half of the case

Arctic Addict · 11-20-2009, 08:20 AM

Hey Matt, I think your on the right path. Sounds like the carbs had some debris from the airbox. Critters have wreaked havoc with sleds stored outdoors for ever. Based on what you've posted so far, I would pick up at least a top end gasket kit and pop off the jugs. Do not reuse any gaskets. Clean and inspect the internals, pay attention to the lower end. Check rod play while everything is open and make sure the rods move freely. Once everything is flushed and clean reassemble. Also it might not be a bad idea to check the exhaust. If it was stored without an exhaust plug, critters love to call the expansion chambers home. Good luck and keep us posted.