Wednesday, June 15, 2011

2001 Husqvarna SM 610 S starting problems.

Its problem of plugged vacuum port.Its not letting the fuel to get through the carb from tank.
There is no fuel pump on the carb bikes. Only on the FI bikes beginning in 2008 in the US. So do not waste time looking for one :-).

You might pull the plastic side cover off the carb and see if you have a rubber O-ring on the pump actuator. Whe you crack the throttle, a stock carb setup will delay hitting the pump actuator and delay the squirt of fuel into the intake. The O-ring mod and adjustment removes all delay.

This can be issue with plugged vacuum port.On the intake manifold there is a vacuum port that should be plugged well. Make sure it is not leaking.

Check your actual jet sizes and idle mixture screw setting, and jet needle clip setting.
Also be sure your exhaust outlet clamp is not loose or leaking.
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on the back of the airbox there is an opening that looks like a hose It let's dirty, unfiltered air right into the intake. If it cracked.Also check that hose.--------
As you mentioned it runs fine with starter fluid. Indicates problem with vacuum port.its clogged.
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The 610 is a little finicky about jetting .
it helpful to run the sparky with the LV can.


main jet--------178 If you modify the airbox cover and aren't running the sparky you might try a 180
pilot jet-------- 45
starting jet---- 85
main air---------200
low air ----------100
needle----------JD red Or a OBDVR Keihein they are virtually the same thing.
position--------- 4 from top
mixture screw ---- 1.5 out Mixture screw is a Zyp Tye Racing type with extended reach.

You can use the heavy O-Ring on the accelerator pump. Once you pull the tank and air cleaner watch the linkage for the accelerator pump while turning the throttle and you'll see where it needs to go, it basically ties the two levers together so that you don't have to get to the half throttle position before the AP begins to work. Merge Racing makes a heavy spring that does the same thing and is a bit cleaner looking than ties the two together with a rubber band.

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there could also be some debris clogging up the pilot jet.or if the bike sat a few months build up in that jet will occur and the bike will run lean and pop on decel badly.plus it has been pretty cold lately to make matters worse.manifold could leak as well from cracks.

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That in the back of the airbox should be you're engine breather and there needs to be a hose that goes there. The hose may go directly from the engine to the airbox or may go from the engine to the frame and then to the airbox but it needs to be there. Misssing that hose can also have an effect on how the engine runs because you are drawing light hydrocarbons off of the crankcase, it needs to be there. There is even a possibility that having the hose there acts like a crankcase ventilator and reduces windage in the crankcase, It needs to be there.
In short that hose plays a big role in keeping you're bike alive and running well.

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tube exits the posterior crankcase and vents into the frame.

max