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Workshop => Carburetor, Intake, and Exhaust => Topic started by: hickwheeler on November 11, 2019, 02:13:10 PM

Title: Starting when hot
Post by: hickwheeler on November 11, 2019, 02:13:10 PM
So when mine is cold fires up fine. But when hot it takes a few kicks. Let it cool down starts first kick. Makes me think I'm a bit rich on the pilot side. What is everyone's thought on this.
Thanks
Title: Re: Starting when hot
Post by: broken1 on November 11, 2019, 03:13:11 PM
What carb you running Gene? My wife's R was doing that with the 38as & like you mentioned dropping the pilot one size fixed the problem.
Title: Re: Starting when hot
Post by: hickwheeler on November 11, 2019, 05:28:55 PM
41.5 pwk Kevin. Just thought I would see if my thinking was correct
Title: Re: Starting when hot
Post by: desertR on November 11, 2019, 08:32:45 PM
My first thought would be that its lean when starting hot, and changing the pilot to a larger one would be needed, but maybe my thinking is off. Could it be fuel boiling in the float bowl ?
desertR
Title: Re: Starting when hot
Post by: hickwheeler on November 11, 2019, 10:35:47 PM
I don't think it's fuel boiling this time of year here
Title: Re: Starting when hot
Post by: Jerry Hall on November 12, 2019, 06:00:39 PM
What carb you running Gene? My wife's R was doing that with the 38as & like you mentioned dropping the pilot one size fixed the problem.
So when mine is cold fires up fine. But when hot it takes a few kicks. Let it cool down starts first kick. Makes me think I'm a bit rich on the pilot side. What is everyone's thought on this.
Thanks

Sounds a little rich to me also.

Check the float level first then check your choke circuit to make sure the rubber on the end of your choke plunder is ok and that it seals on it's seat when the choke is off.  If the choke circuit is not allowing any fuel to pass when hot, drop the pilot a couple of jet sizes and see if it helps the condition.

When we machine a PWK, the shroud that surrounds the needle has to be removed to machine the air flow passageway to 41.5mm.  The special moulded o-ring that provides the seal between the shroud and carb body often does not reseal 100% because we cannot get new o-rings from Keihin.  When this o-ring does not seal, the pilot jet can get fuel from the main jet circuit and vice a versa.  This is another reason that I prefer not to bore the PWK series of carbs.  I do not have a solution for you if this o-ring is your problem.
Title: Re: Starting when hot
Post by: hickwheeler on November 12, 2019, 07:47:42 PM
Thanks for the replay Jerry. Just some info to you. Jets r us does sell the oring you are taking about. It escapes me at the moment what they call it
Title: Re: Starting when hot
Post by: hickwheeler on November 12, 2019, 07:53:18 PM
It is called o-ring jet block.
Title: Re: Starting when hot
Post by: broken1 on November 13, 2019, 01:46:54 AM
I've also heard of it referred to as a jet tower o-ring... I purchased a few from jets-r-us & they were a direct match to the oem keihin o-rings but a friend ordered some generic brand from another source & they were slightly thinner & none of them worked so only get them from jets-r-us.
Title: Re: Starting when hot
Post by: Langbolt on January 17, 2020, 01:13:33 PM
@hickwheeler What is your Air Screw set at ? Try turning it out a 1/2 turn :)