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Please help lots of spark knock at speed

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Please help lots of spark knock at speed

Postby Suzuki360 » December 6th, 2004, 8:04 am

Last year I rebuilt the Tillotson HD carb on my Suzuki 360 free air engine. I didnt pull the welch plugs because it seemed like a PIA. I got the engine to run but when it would get going over about 20mph I could hear spark knock and there was no power. I tried richening the mixture with the high speed screw but it made no difference in how the sled ran. This led me to believe I was getting no fuel from the high speed jet.

So now I have the thing apart and the welch plugs off and there seems to be no restriction. Where do I go from here? Thanks
Suzuki360
 
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Joined: October 13th, 2003, 12:50 pm
Location: Saginaw, MI

Please help lots of spark knock at speed

Postby jeteralfonso45 » December 6th, 2004, 8:08 am

knocking usually means your timing is off, your running to hot of plugs ,to lean a fuel setting or combustion chamber caoted with carbon
Steve
1972 Sno-Jet Start Jet Deluxe Plus 2 338
1970 Ski-doo TN'T 340 (335)
1979 Ski-doo Citation 300
1971 Arctic cat lynx 292 , 303
My Vintage sled website

http://Jeteralfonso4500.tripod.com/

It'
s a work in progress
jeteralfonso45
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Please help lots of spark knock at speed

Postby Suzuki360 » December 6th, 2004, 9:21 am

I know what causes knocking, what I dont know is why opening the high speed needle all the way did not have any effect on how the sled was running. It should have flooded and fouled the plugs, right?
Suzuki360
 
Posts: 6
Joined: October 13th, 2003, 12:50 pm
Location: Saginaw, MI


Please help lots of spark knock at speed

Postby jeteralfonso45 » December 6th, 2004, 10:09 am

yeah definatley sounds like a fuel problem sounds like you need to rebuild the carb
Steve
1972 Sno-Jet Start Jet Deluxe Plus 2 338
1970 Ski-doo TN'T 340 (335)
1979 Ski-doo Citation 300
1971 Arctic cat lynx 292 , 303
My Vintage sled website

http://Jeteralfonso4500.tripod.com/

It'
s a work in progress
jeteralfonso45
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Posts: 221
Joined: November 30th, 2003, 7:03 am
Location: CT

Please help lots of spark knock at speed

Postby Speedway73 » December 6th, 2004, 10:22 am

How old is the fuel in the tank??
"If it ain't an SRX...well...it's probably something else"!!
Speedway73
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Location: Flint,MI.

Please help lots of spark knock at speed

Postby Suzuki360 » December 6th, 2004, 12:34 pm

Fuel is fresh.

My only concern is I rebuilt the carb once and had the above problems. If I rebuild it again why should I expect different results?
Suzuki360
 
Posts: 6
Joined: October 13th, 2003, 12:50 pm
Location: Saginaw, MI

Please help lots of spark knock at speed

Postby jeteralfonso45 » December 6th, 2004, 1:27 pm

Try and run it at half choke and see if there is a difference.
Steve
1972 Sno-Jet Start Jet Deluxe Plus 2 338
1970 Ski-doo TN'T 340 (335)
1979 Ski-doo Citation 300
1971 Arctic cat lynx 292 , 303
My Vintage sled website

http://Jeteralfonso4500.tripod.com/

It'
s a work in progress
jeteralfonso45
Member
 
Posts: 221
Joined: November 30th, 2003, 7:03 am
Location: CT

Please help lots of spark knock at speed

Postby needles » December 6th, 2004, 2:08 pm

check your metering lever. it should stick up .005 to .020 from the surface of the main body casting of the carb. this is what opens and closes your needle to allow more or less fuel into your engine. also you can make sure that your spring that puts pressure on the metering lever is not streached out to far this will put to much pressure on the needle not allowing it to open correctly. if this is not it check all passages and holes for crud. if you dont have a in line fuel filter going to your carb get one asap. One other thing to check that is easy is to make sure your exhaust is not plugged, critters like to build nests in there.
needles
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Location: Meadville,pa,usa

Please help lots of spark knock at speed

Postby indyized » December 6th, 2004, 2:19 pm

[quote] check all passages and holes for crud.

Clean er again and reinstall, Should fix the problem.
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Please help lots of spark knock at speed

Postby Suzuki360 » December 7th, 2004, 11:04 am

Thanks for the replies. I do have a fuel filter, one of the screw on ones. I did pull the carb apart and mess with the metering lever once with mixed results last year. I am putting a new lever and spring on this time.
What can I use to measure the distance? The directions I had said make the lever even with the carb housing, which is how I tried to set it. Which way allows more fuel and which allows less? About all I have to measure with is a set of feeler gauges.
Suzuki360
 
Posts: 6
Joined: October 13th, 2003, 12:50 pm
Location: Saginaw, MI

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