Snowmobile Fanatics banner

1 - 10 of 10 Posts

·
Registered
Joined
·
108 Posts
Discussion Starter #1
This is a weird one, any insight would be appreciated. I just purchased an 89 & a 91 exciter. The 89 needed carbs overhauled and a new track, did all that & it was great. So about two weeks later picked up the 91, almost identical machine. It would only run with the choke on so I tore apart the carbs and found a plugged idle jet. I cleaned them out, put them together and all seemed fine for about an hour. Then it starts to load up horrible. If you shut off the fuel, just before it runs out of gas it takes off like a scared rabbit.
So, must be bad carbs, right. So today I went through them again. Floats good & correct height, needle & seats great. Choke pistons aren't bleeding off. So tear apart fuel pump. Good. Remove fuel tank and check ventilation system, fine. You get the picture. All looks good so decide to go for a ride and see. By the way both machines have factory jetting.
So the wife & I are out for about 45 minutes and all is great. Stop for a 5min break and go to leave and BOGG!! And I mean it barely moves. Here we go again. At least I have daylight this time. I'm on the trail so I can't take them apart but I pull the carb pistons to see which one is slobbering. No slobber but LOTS of vapour. What the??
So I take it home to "start ciferin' agin" and the wife gets stuck so I go to bail her out. Now she is no where near as aggressive as I so she did not notice her machine was VERY loaded up as well. Thats when a light came on. I just don't know if it's the right one. Its about 20 degrees warmer today than the last time we were out. These Exciters have a hot water shut off valve for the carbs. They are both stuck so I can't shut off the coolant flow. Could this be causing perculation? I will get new valves but what temperature should they be used at? It's about -2c today and the snow is hard so not very much is getting thrown on the heat exchangers.
I've been around machines for far too long but never owned snowmobiles before. Any insight would be nice. Thanks.
 

·
Registered
Joined
·
4,755 Posts
some people don't run the carb warmers ,also did you ever notice any floaties in the carbs, alot of times on machines newer than you have ,had to put little fuel filters on the lines going to the carbs ? why do not know but every one i have done that to runs fine after words
 

·
Registered
Joined
·
660 Posts
I do not remember if the seats have o-rings or not on those. But If they do, Spray something on the seat, with the needle in the closed position (holding) blow(lightly) through where the fuel line hooks up to the carbs and see if you see bubbles on the outside of the seat. Will tell you if you have bad o-rings and even with the needle and seat working properly...still flood. Found this on a sled recently.
 

·
Registered
Joined
·
985 Posts
before you buy new water valves, put a pair of pliers on them. even brand new there extremly hard to turn. but if its 30 deg. i doubt thats your problem. my guess is since it ran good until you stopped. then it started bogging that somehow your flooding the crankcase. either bad needle and seat, or fuel pump. as a matter of fact my guess is needle and seat. they are 15 and 17yrs old.
 

·
Registered
Joined
·
108 Posts
Discussion Starter #6
Fuel pump holds 20" vaccuum, don't think it's that. Even though the needle & seats hold pressure it sure feels like it. Can a guy get Viton needles for the Mikunis' aftermarket? Tommorrow is my day off & we just got another 5" of snow so I'll do some more playing then. Thanks for the help guys.
 

·
Registered
Joined
·
108 Posts
Discussion Starter #7
Finally got them fixed. Turns out factory jetting chart is incorrect. How do I clear this posting?
 

·
Registered
Joined
·
3,029 Posts
mods might remove it, but keeping it up for others to reference isn't a bad idea either. Exciters are very picky about jetting and temp. Exciters are jetted way fat from the factory and will always have that classic bog unless you dial it in every time the temp changes.
 

·
Registered
Joined
·
108 Posts
Discussion Starter #9
Well I thought I fixed it, I was wrong. But today I did find the REAL problem. Bearing in mind I bought this used, I wasn't aware of this. Once upon a time it was ported, Then a piston seized and scored a jug. A stock jug was put on ONE SIDE ONLY! I'm screwed. Its only about $500 US for a jug. NICE!
 

·
Registered
Joined
·
660 Posts
ebay.....I have an old 87 sitting out at my wifes family farm...Make no promises as to what the motor looks like after sitting for 3 years (outside)...But if you can't find one let me know. I don't know the next time we will be out that way again, its 4 hours away from me. But next time out I will pull the jugs and see what they look like....If you haven't found something by then. I am guessing I won't be up their again till spring. Sorry.
 
1 - 10 of 10 Posts
Top