jlo440 seems to not want to run

[chris lewis]

hello everyone,

i just finished rebuilding my jlo440 and installed it back in the bigmax. i tried to start it but cannot get it running. if i spray ether im the carb, it will run...but even with fuel coming back to the carb, it jsut does not seem to want to run. the battery is dead so i am cha rging it now...just have been pull starting it...and pull starting it...and pull starting it.

the carb is a walbro wr as I recall. it h been completely rebuilt last year...all new diaphragms etc.
it does seem to be pumping fuel...but seems like there is air in the return line...is it sucking air?
i have all brand new intake gaskets and phenolic spa cers between the intake and the engine and new gasket betweenthe intake and carb.

where should i set the idle screw on the carb as a starting point?

thanks
chris

[jpswift1]

Chris, First off, how is the spark? Did you try putting new plugs in? I personally would get rid of the Walboro carb........those and Tillotson carbs are just way too unreliable and sensitive. I'd use a 32-34mm Mikuni roundslide instead. You can find them on ebay off old snowmobiles pretty cheap.

[Bazooo guy]

If it starts with ether than you have spark.
Did you set the timing when you assembled it.
Set the needles at 1 turn open till you get it running.
Make sure there are no leaks in the fuel line.
Air bubbles in the return line are normal till its running.
Spray a gas oil mix into the carb instead of ether.(if its a 2 stroke)
If you flood it pull the spark plug and dry it and crank it over without the plug in to clear the cylinder of fuel..
Dont use the choke if you spray gas or ether in the carb.
If you have good compression and spark at the right time and fuel it should
start.
Set the idle screw so it just starts to open the throttle plate.
Keep pulling ...

[chris lewis]

Hi Bazoo guy.

Yes, it will start on ether...and do not want to continue to do that..especially with a fresh engine. It is a 2 stroke.

There are two needles on it...an idle screw and I guess a high speed needle.

Another question>>>> out of the Stator plate there is a brown wire..it is a ground. It is inserted in the female plug. On the wiring harness from the ignition switch etc, there is NO brown wire in the male plug coming from the ignition switch, wiring harness etc.

Is there supposed to be a brown ground wire? Otherwise, how would one kill ignition and stop the engine?

I will look for a Mikuni 32-34.

Thanks
Chris

[chris lewis]

Regarding the Mikuni, since the Walbro is a diaphragm style pump, would I just put a vacuum powered pump (like on a B@S engine) inline? is that what others have done?

Thanks
Chris

[jpswift1]

Regarding the Mikuni, since the Walbro is a diaphragm style pump, would I just put a vacuum powered pump (like on a B@S engine) inline? is that what others have done?

Thanks
Chris

That's exactly what you would do. Something like this would do the job:

VINTAGE MIKUNI FUEL PUMP RACE KART SNOWMOBILE SINGLE 1CY McCULLOCH ROTAX BRIGGS | eBay

[Bazooo guy]

The brown wire is a ground from the stator. It should be grounded all the time.
The ignition switch connects the 2 black wires from the coils (in the off position) to kill the ignition.
You should pull the spark plugs and turn the engine over to prime the carb untill you see fuel flowing thru the return line.
Heres the walbro manual.

http://wem.walbro.com/distributors/s...viceManual.pdf