Ok enough is enough 1978 SRX 440 Carb problems

W

woodsy

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Dec 24, 2008
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chicago
I have been fighting carburetor problems forever, please can ANYONE give me correct carb settings. The carbs I believe to be stock 36 mikunis. Both float bowls have a horizontal mixture screw in them with the word RICH and a counterclock wise arrow. There are no white caps on them anymore. Secondly, the pilot air jet screw, the one on a 45 degree angle, what is that setting. I can not get this thing to idle, or run at all. I will PAY for the information and results, seriously, I have no problem sending anyone 25-50 dollars for nothing more than the correct info to get this running again.

Carbs have been totally cleaned this week. It ran a little fat last year, but never wanted to idle it was either running or not but it ran 87mph on handheld gps, so I know its a runner, just carb issues killing me. I am ready to buy 2 new carbs if needed. PLease HELP

Oh ya got 14 inches of snow, and no sled :brr
 
I CAN GIVE YOU ALL STOCK SETTING FOR THOSE CARBS. YA KNOW YOU POSSIBLEY COULD HAVE OTHER ISSUES IF IT WON,T IDLE. THAT ENRICHNER WAS THE POWER JET, WHICH TO TELL YA THE TRUTH , WERE A PAIN IN THE ***. WHAT I DID WAS BYPASS IT AND JUST INCRESE MAIN JET SIZE. ALSO PART OF THE IDLE PROBLEM ALSO COULD BE IN THE WAY YOUR SLIDES ARE SYNED. LET ME KNOW IF YA NEED THOSE SPEC,S. 3:16 (yammie tony)
 
I need any specs and settings you can give me to get back to the stock base setup and then I can atleast try to diagnose any other issues. I would really like to simplify things. Last year it ran like a scolded cat after 4000 rpm. It was a little boggy, soft on the low end and I never got it to idle at 1800 or so like they are supposed to, but everyone says there not the type of sled that just idles around and cruises. I love the sled but am ready to strangle something. NOONE can give me real factory settings and its driving me nuts. I would be very grateful to keep dialog open while I get it back running for any other suggestions.
 
Tony,

Let me also say last year the sled ran good, easy start, high idle. This year easy start 2 weeks ago, then the comet clutch literally blew apart, so I took the time while my clutch was on order to clean the carbs, now its extremely hard starting. Thanks so much
 
WAIT BEFORE I GO ANY FARTHER HERE. YOU BLEW UP A COMET CLUTCH ON THIS SLED ? DUDE, I THINK YOU TOOK YOUR CRANK SEAL OUT. THATS WHY IT WON,T IDLE. 3:16 (yammie tony)
 
YAMMIEGOD3:16 said:
WAIT BEFORE I GO ANY FARTHER HERE. YOU BLEW UP A COMET CLUTCH ON THIS SLED ? DUDE, I THINK YOU TOOK YOUR CRANK SEAL OUT. THATS WHY IT WON,T IDLE. 3:16 (yammie tony)
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Let me clarify, blown up. 1 weight broke then the centering bushing in the plate dropped down so the clutch was cocked to one side, it happened at about 10mph, didnt drive it but 20 feet to the trailer. I looked at the crank seal today before on the new clutch. No visual signs of damage.
 
1978 SRX CARB SPEC.
VM36 MIKUNI
PREFIX 8G9
MAIN JET - #310
POWER JET - # 80
AIR JET - #2.5
NEEDLE JET - #6DH3-3 POSTION
CUT AWAY SLIDE - #2.0
PILOT JET- #30
FLOAT ARM HEIGHT #18 mm
IDLING RPM - 1500 +/- 100
LOW SPEED TUNEING CAN BE DONE BY ADJUSTING THE TROTTLE STOP SCREW AND PILOT AIR SCREW. COLD START UP ENGINE SHOULD RUN 3000/3500 . BY TURING PILOT AIR SCREWS OUT FROM SEATED POSTION, YOUR MIXTURE WILL BECAOME LEANER. THAN TURN SLIDE SCREW COUNTER CLOCK WISE UNTIL IDLE DROPS TO SET RANGE. 3:16 (yammie tony)
 
If you are still using the main jet adjusters and powerjet stuff be sure that the o-ring between the nozzle and the float bowl is good. the sled will run like crap if that o-ring doesn't seal well.
 
phazerguy said:
If you are still using the main jet adjusters and powerjet stuff be sure that the o-ring between the nozzle and the float bowl is good. the sled will run like crap if that o-ring doesn't seal well.
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Thanks Tony, and yes I saw that the o-rings were junk, almost flat. I guatantee they are not working like supposed to. Does anyone know if there is a carburetor you can buy new that will replace these Mikuni 36's Powerjets and perform the same or better?
 
YAMMIEGOD3:16 said:
38 ROUND SLIDES BOLTED ON AND WORKED GREAT, THE SRX SHOULD OF HAD THESE TO BEGIN WITH . 3:16 (yammie tony)
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Part number or link to some if possible. Does mikuni make a dedicated snowmobile carb? Or are they used for all applications, thanks so much tony
 
You still may have a crankcase leak. That can make a sled idle poor and not respond to carb adjustments. On top end the engine will run fine.
To check for that, the crankcase can be pressurized with the intake and exhaust openings blocked. A pressure gauge should hold steady. I don't know if those engines ever had leakage between the cylinders at the crank.
 
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