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85hondaatc125m
10-24-2006, 06:43 PM
Well...it all started the other day when I tried to start my 1973 Skidoo Olympique 400. I went to go pull it over, it fired for a second but then died and wouldnt start again. I tried some other days to start it but had no luck at all. So I went out and squirted some gas straight into the carb and it would fire and run for about 10 seconds, if that, but then it would just up and die nomatter what you did. It has very good spark so I am not sure why it wont start. Anyone have any ideas, im not sure if gas is getting to the carb or not but I will go check, Please give your best ideas, Thanks in advace, Clint

85hondaatc125m
10-24-2006, 07:45 PM
well... The gas is in the line leading to the carb, but it is just on the bottom of the line and not going up to the carb, so does anyone know why it wouldnt be getting up to the carberator? Please, anyone, just some suggestions?

84honda200s
10-24-2006, 09:30 PM
when my everst did that it was the palse line from the fuel pump to the engine but i dont think you have a fuel pump. does your evgine have a white plastic thing on the bottom of the carb. if so it may be pluged up. if thats not it it could be bad compression.

troy
10-24-2006, 10:02 PM
Theres was two different types of Carburetor for ski doo, Tilson and mikuni Carburetor. first thing you need to do if find out which one you have. I'v had so many ski doos with both types, even had one called a butterfly carb by yamaha.

From what i understand from your post, "So I went out and squirted some gas straight into the carb and it would fire and run for about 10 seconds", I'm saying you have a tilson carb. Because a mikuni carb on any ski doo had been equiped with a primer.

I worked on these alot and hated every minute of it, simply because ski doo discountined this back in the 80's. parts are very very hard to find. Two things could be wrong.

1. You have no vacuum.

2. The fuel pump die-a-fram is tore or riped. Reason for this old age. if your take your carb apart you will see a black die-a-fram with a little round metal plate on it, this is your heart and soul of you ski doo AKA the fuel pump.

There is a way to test this to see if that is the problem. take the vacuum line off the engine and (it's going to get weird from here) put it in your mouth and suck and blow back into it some what fast. If you can see gas going into the carb, your carb is it good shape. and you have compression OR vacuum problems. If no gas is going into the carb doing what i say then your in trouble with your carb.

P.S clear gas lines would help in seeing if the gas is moving. If you don't have clear gas line, little at the fuel filter (white cup at the bottom of the carb)

85hondaatc125m
10-25-2006, 12:02 AM
I will check tommorow what the carb is, but it has a choke and not a primer, it also doesnt have floats. But what gets me is it ran perfect the day before it started having problems, it would run fine and I could hold it open and it would start with absolutely no problems, and then the next day it only started for 1 second.I will check and make sure the vacum lines are in place and hooked to everything, and if that doesnt work I will take the carb apart and take some pictures of it cause I am not sure quite what you are talking about Troy.

MTS
10-25-2006, 03:01 PM
Didnt foul the crap outa the plugs? or split a vaccume line? Rebuild kits are easy to get for the tiltson's run about 50$ if i remember correctly

troy
10-25-2006, 03:15 PM
I will check tommorow what the carb is, but it has a choke and not a primer, it also doesnt have floats. But what gets me is it ran perfect the day before it started having problems, it would run fine and I could hold it open and it would start with absolutely no problems, and then the next day it only started for 1 second.I will check and make sure the vacum lines are in place and hooked to everything, and if that doesnt work I will take the carb apart and take some pictures of it cause I am not sure quite what you are talking about Troy.


sounds to me as a 100percent tilson carb. The give away was the choke

85hondaatc125m
10-25-2006, 06:31 PM
Alright, thanks for your help so far guys, I will check the vacum line that leads from engine to carb and make sure it is free flowing, if not I will try to do some searching on a carb kit, and if that is too much, I mgiht just take the carb off and take it to a back door skidoo mechanic.

85hondaatc125m
10-25-2006, 07:46 PM
Some new information, and I need help ASAP! I went out side and I tried to blew into the line leading to the engine and it was clear, then tried blowing in the hole that leads from carberator to engine and I couldnt blow into it, so that is my problem, it is not getting the vacum power from the engine. So I took the carb apart and took out the 2 plastic yellowish "filter type things"(ill picture them below), and when I took them out I could easily blow into the carb. So my question is what do these "filter things" do, and if I left them out to see if it would start would I wreck anything?
Here are a couple pictures, the first to are of the "filter things"
http://img.photobucket.com/albums/v66/Shotgun38/HPIM2128.jpg
http://img.photobucket.com/albums/v66/Shotgun38/HPIM2127.jpg
Thanks in advance and please reply ASAP

troy
10-25-2006, 08:57 PM
:) yup you need them in your carb to work. they tell or make up where the fuel is suppost to go., there also should be a black one in there with a metal plate on it, this makes up the fuel pump, the metal plate pushes up on the needle valve. I'm trying to remember how this goes now, been about 6 years sense i touch one, Every ski doo i'v owned that had a tilson carb on it including my 300 cc singal banger olympique i'v converted to a mikuni carb.



If your look at the carb you see where the vaccum hose goes, right above that plate will be the black die-a-fram, check that one to see if theres any cracks, tore, anything that might cause a problem in creating a vaccum for the fuel to move.

I'v seen some pretty weird thing with these carbs. If you can and you are like me and love your ski doos, look around for a mikuni carb kit for you ski doo, You will thank your self later. Trust me. tilson is the only carb i'v owned thats left me stuck in the middle of no where because of some thing like this. This is why i started to carry a spare carb with me. Ya thats right A SECOND carbs with me in the tool box or in my case under the seat of my elan..LOL!

Let us know whats going on.


P.s I ment for you to blow into the carb vaccum hose, example from your mouth into the carb. no biggy. lol i done that a few times

85hondaatc125m
10-25-2006, 09:10 PM
Well, i Looked around and nothing seems to be broken. And you said there should be another one of those thing but black? I dont have that, this is how it is setup.
from the bottom of the carb coming out
Gasket, then there is one of those screen thing that I have in my picture, then there is a metal plate, then there is another gasket, another screen thing and then another plate. So I am guessing I might need some new one fo those plastic screen things? I would think about switching to a mikuni carb but I would like to keep it stock and I think I will be selling it at the end of winter anyways :(

troy
10-25-2006, 09:24 PM
so you can't find some thing like this? it should be there

85hondaatc125m
10-25-2006, 09:35 PM
That part that you have in your first picture I havent came across it in the carb, where is it located?

85hondaatc125m
10-25-2006, 09:40 PM
Here is a picture of the only 2 plates I have, Located beside the carb on both sides, and in front of the carb is the 2 screens, and there are also 2 gaskets but they are not pictured.
http://img.photobucket.com/albums/v66/Shotgun38/HPIM2126.jpg

hrc200x
10-25-2006, 09:45 PM
While your carb is apart check to make sure the needle is free, seems like your problem could also be a stuck needle, kinda weird it would stick a day after it has ran, but its possible.

There used to be a glass ball repair kit to replace the needle, the glass ball would never get stuck again, but I think its not being made anymore.

troy: can you give a run down on how to switch to a mikuni carb? I know the later elans came with round slide carbs, probalby mikuni's. They have a fuel pump and no return gas line which would be nice. What size carb do you use? What about a carb boot? Thanks.

85hondaatc125m
10-25-2006, 09:49 PM
I will try that GRC, but where is the needle located? Is it loated on the die of teh carb or where? Thanks.

troy
10-25-2006, 09:51 PM
LOL..going though a 100 cd's of stuff i have i came across some thing that will help you a great deal...

hrc200x
10-25-2006, 09:54 PM
AFter you have removed all of the 6 or 8 screws holding the diaphrams on and removed the diaphrams you'll see a teeter-totter (SP?) thing with a spring under one side and a needle under the other side, holding the carb over your head but keep it at the angle it would be if it was mounted on the motor push on the spring end of the teetertotter and the needle should drop with out any effort, if it doesn't keep trying, try to shake the carb a bit, if it won't come down thats probably your problem.

troy
10-25-2006, 10:04 PM
.

troy: can you give a run down on how to switch to a mikuni carb? I know the later elans came with round slide carbs, probalby mikuni's. They have a fuel pump and no return gas line which would be nice. What size carb do you use? What about a carb boot? Thanks.[/QUOTE]

at the time i went to a ski doo and asked for a mikuni carb kit, told them what year, model, and what carbs was on it. The kit should come with a new fancy fuel pump, carb, throttle cable, primer, a gas line tee, gas line, filter, and the boot for the air box and the carb to the engine.

You have to make 100 percent sure it's jetted right for that engine. Trust me i know, i put the wrong one on my 12 elan and made it half way home and ending up waiting half a hour before continuing home, due to the engine over heating. The carb was giving the engine to much fuel..

But this i will tell you, you will notice a big difference in your machine, preformence wise that is. seem with mine it had more pep, fast pick up time, and less bogging :) .. i can't remember how much i payed for mine. but it was worth every cent. it was a 12 elan with the first slide suspention it was made in 79. But like all good things i sold it.

Yes you are right i think it was 85 ski doo switch their carbs to mikuni's and dumped the tilson carb, some thing like what on mine and you bikes.. in fact i can take the carb off my bike and fit it on a elan just by adding a fuel pump, , same size motor. and my bike is a 200ern tri moto

85hondaatc125m
10-25-2006, 11:40 PM
I have a question, If I hold the diafram(filter screen thing) right to my lips and blow at it, should air be able to go through the diafram? Thanks, Clint

troy
10-26-2006, 01:22 PM
should be a little resistence, but ya you should be able to blow throught it

85hondaatc125m
10-26-2006, 07:10 PM
Alright, they must be old and not letting air through, because when I blow on it no air at all goes through, so I guess I might get a kit for that type of carberator, the kit inludes everything you had in the 2 nd picture that you ever posted for about $30. And I will try from there, thanks troy!

troy
10-26-2006, 07:31 PM
Alright, they must be old and not letting air through, because when I blow on it no air at all goes through, so I guess I might get a kit for that type of carberator, the kit inludes everything you had in the 2 nd picture that you ever posted for about $30. And I will try from there, thanks troy!


no problem , what i'm here for..Like you said if your going to sell it after the winter, no point in coverting carbs, i know i won't.

I'm very surpise they still make kits for that carb, i know they where slim picking about 5 or 6 years ago..

Keep us inform how things turn out....


Later man:)

hrc200x
10-26-2006, 09:12 PM
The needle was free?

85hondaatc125m
10-26-2006, 09:58 PM
I havent checked the needle and stuff yet, ill let you know when I do.

85hondaatc125m
10-28-2006, 04:11 PM
Went out and checked out the needle situation and the needle wouldnt move unless you gave the carb a good shake and it was all gummed up and stuff, so I guess I will just wait until I can get money for a carb kit and then I will buy it and hope that works.

hrc200x
10-29-2006, 10:09 AM
Take out the phillips screw which will let you remove the spring, needle, and rocker thing. Try to lube it up with a little WD40 or somthing reassemble it and see if that helps.

85hondaatc125m
10-29-2006, 11:15 AM
I did soak it down with WD-40 and it was still sticking so I will have to try some carb clean maybe?