Forum - Briggs & Stratton Racing
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Speed wagon85

Registered: 10/12/12
Posts: 1
Reply with quote  #1 
We run the Local 206 in our Kart. My son is fast as heck for 2-3 laps and then the power goes away. It drops .30 Seconds or more as the race goes on. If a caution comes out he is good under green for another lap or two. We have sent the engine back and dynoed it and it looks great. The chassis has been gone through over and over by the best set up guys at the track. The season is over now and we had this problem all year. I think I figured my issue out. I just want to know if I am close to being correct since I am new to karting. We ran a flat head last year and that had a 7 degree mount on it. We used the same mount for the animal. I noticed we are the only ones that do not run a plat mount. With the engine at a 7 degree pitch and a blue plate restrictor, is it causing the card not to fill up to the proper level, because the float is tilted with the pitch of the mount?
It makes sense to me that if you turn the carb to a 7 degree angle you have less holding capacity. Even with the adjustability of the carb I can not make it level. Is it using up the gas in the bowl on the first two laps, and starving the rest of the race? Any thoughts.
BriggsRacing1

Registered: 06/22/11
Posts: 188
Reply with quote  #2 
Speed Wagon,
                    I don't like hearing that but I am sure we are looking at something simple.  When the power goes away are your rpm's falling off, is the engine missing, how is it acting?  What is your float level set at?  Your needle position?
For starters I do not think your angle mount is the issue.  While we recommend a flat mount for ease and consistency of the fuel level in the bowl it can be overcome through adjusting the float level.

Some thoughts and initial ideas:

- If you float is way off or your needle setting you could be looking at either a rich OR lean condition.  Without more information it's hard to say.  I would recommend reviewing our video on setting the float but also look through our latest news to find our carbuetor guide.  Whether this is your core issue or not it's a great piece to read and keep with you at the track.
- Could you be pressurizing the engine or have a fuel restriction?  You catch can NEEDS to be non-restrictive and vented to the atmosphere. Any restriction and that pressure will fight against the engine.  If your tank vent is partial restricted OR your pulse line to your pump fills completely with oil it will limit fuel feed.  I would double, double check this.   Look your tank vent cap over, maybe drill an additional hole in your catch can to make sure it isn't restrictive, and make sure your pulse line isn't filling it.

- Spark plug - Does it have a CHAMPION logo on it?  There is a similar plug available on the lawn and garden side of our business that we regularly see, when brought into racing, that can cause intermitent symptoms.  The heat range of this plug is what the issue is.
- Plug gap - Please go ahead and open it up to .040".  If this is a rich issue the PVL firing power will clear a larger gap and clean up a momentary rich condition.

If the engine dynos fine, your son is fast for a couple of laps before falling off.  I would lean towards a full delivery, a carburetor setting, or pressurizing situation.  The carburetor setting I assume was checked at the dealer when tested.

We don't have a lot of time to figure this out before the weather turns against us.  If you want drop me an e-mail at Briggsracing@basco.com with your phone number I can give you a call to work through this. 

I'm sure it's something simple and we will get your son back to fast! 
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