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Discussion Starter · #1 ·
So I recently bought an Indy 400. I have hooked up all tubing and I put oil and bled the oil pump. I put in coolant and propped up the front end to try and burp it. I was gonna start it to burp it some more to get rid of air bubbles but I'm not getting fuel. I checked the tank to make sure the tube in the inside was intact and it is. Fuel won't even make it to the shut off valve. I even syphoned the fuel to the end of the tube right before the shut off valve and it didn't pull any. My guess is maybe the fuel pump. But I'm not sure how the electrical works on this older machine. How does the fuel pump even function without the battery? I would love some insight and help. The guy I got it from got it running by spraying some stuff into the carb and it ran and stayed running for awhile. I also have not cleaned the carbs. I don't know if that has something to do with it either. I'm just trying to avoid buying a new fuel pump unless I absolutely have to.
 

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The easiest way to prime the lines and fuel bowls in the carbs is to "blow" into the tank with your mouth. That's how I do it and then these old sleds always start on the first pull. If you don't want to do that then spray some oil impregnated either (they sell stuff like that) into the carbs and then start up and the fuel should fill the lines etc just since the impulse pump should pump like normal then.

Your call.

Steve 80 Blizzard 7500+ dual carbs.
 

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Discussion Starter · #3 ·
The easiest way to prime the lines and fuel bowls in the carbs is to "blow" into the tank with your mouth. That's how I do it and then these old sleds always start on the first pull. If you don't want to do that then spray some oil impregnated either (they sell stuff like that) into the carbs and then start up and the fuel should fill the lines etc just since the impulse pump should pump like normal then.

Your call.

Steve 80 Blizzard 7500+ dual carbs.
What do you mean blow into the tank? Like the main gas tank?
 

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Yep, take a deep breath and take the cap off the tank, pressurize the tank with your breath (breath out only lol) for about 30 seconds till the lines fill up and the bowls fill up. Release and you'll have fuel where you need it and it'll start immediately. An easy "preseason" trick (around halloween no less) to start the sled. Don't have to do that with fuel injection though!

Steve old carb guy still alive so it must not be too dangerous!
 

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Discussion Starter · #5 ·
Yep, take a deep breath and take the cap off the tank, pressurize the tank with your breath (breath out only lol) for about 30 seconds till the lines fill up and the bowls fill up. Release and you'll have fuel where you need it and it'll start immediately. An easy "preseason" trick (around halloween no less) to start the sled. Don't have to do that with fuel injection though!

Steve old carb guy still alive so it must not be too dangerous!
Okay so I did that and it started for a second and then stopped. Now it’ll sputter but won’t stay in an idle.
 

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2 stroke engines will give off a lot of smoke until the engine gets warm, especially after sitting a while. It's normal.

So you know.. the fuel pump operates off of an "impulse" line on the crankcase. The pressure/vacuum from the crankcase, which is caused by the upward and downward travel of the piston, drives the rubber diaphragm in the fuel pump. Old pumps can become brittle with age and may need to be replaced or rebuilt.
 

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LOL "those sleds always start on the first pull"...Yeah sorry but no that isn't true. And don't use ether of any kind that stuff was meant for diesel engines. Use a small amount of gasoline down the each of the cylinders to get it going.

Clean the carbs as well top to bottom and use a small piece of wire to clean the passages and jets. Also the carburetors on that sled are Mikuni round 34mm in case you need a kit as that kit will come with needle/seat and gaskets for it.

I had a Indy 400 and those are nice sleds and can be setup with some nice clutch work as well. Also most likely if it has the fuel pump bolted to the tunnel/body on the bottom then it is most likely the original and should be replaced. As they get older the parts inside can dry out and cause the fuel pump to not work.

Pick up one of these as it is the same one from Mikuni. Only difference is that instead of bolting it to the tunnel you will just use some zip ties to tie it off to something and the hose that goes on the bottom now goes on top. They just switched them around is all.

 

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Still don't agree with you guys on rebuilding fuel pumps and never will. 12-15 bucks for a rebuild kit vs 17 for an aftermarket pump or 28 for mikuni. I've had dealers, shops and myself rebuild pumps in the past and every one would last a month maybe 2 and then be dead again vs a new pump. I've got a cheap aftermarket pump that lasted 10 years in a snowmobile took it put it in the back as a backup and last year after sitting for 8 years put it in another snowmobile and it ran perfect. Even my friends that have tried rebuilding won't do it anymore even when using the name brand kits
 

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Unless the pump had water in it and has frozen, I can usually rebuild a pump
I have kits on the shelf!
 
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