Over heating issues with my Briggs

Running at about 450°, with a 52 jet, and no tape.
Kart is not tight, not leaking fuel
Don't want a bigger jet, as the air is dense at this time of year.
Is this a spark plug issue?
Thoughts in how to get my temp. down?
Thanks
 

Ted Hamilton

Design Drafter / Racer
Kart that is binding can cause extra heat... Hot air this time of year is LESS dense, so mixture tends to be richer in effect -- not leaner, Plug heat range could possibly be issue, adding more fuel should help cool, but you don't want that at the expense of carb tune... Change to a more open flywheel screen?
 
Kart that is binding can cause extra heat... Hot air this time of year is LESS dense, so mixture tends to be richer in effect -- not leaner, Plug heat range could possibly be issue, adding more fuel should help cool, but you don't want that at the expense of carb tune... Change to a more open flywheel screen?
Thanks for the reply.
Any suggestions on type of plug to try, or different heat range plug?
I have some autolite plugs I use for my clone, (no electrode). I wonder if that would work in my flathead?
 
H

How competitive are you in your class, asking because being gear bound will definitely effect the temp. If your keeping up with the front of the field I would definitely check timing, and bore of carb.
We have 13 to 15 karts in our class, and I'm currently leading the points. I have a top 3 kart most nights, so it's competitive.
But I'm just trying to improve my game, as I feel I need to do that to stay on top of this very competitive field.
Thanks for that info!
 

flattop1

Dawg 89
What plug are you using now ?
The autolite 411. Is my go too for a stocker .
You have the air deflector on the coil ?
 
Each heat range in the Denso plug line drops the cht 10-15*F. Ie, if you're running the typical Autolite 411 equivalent in Denso, it's an ND W24 FS-U plug. Going to one step colder heat range plug (ND W 27 FS-U) will pull 10-15* out of the engine -- that'll put you in a bit safer range.
You can go colder yet to a 31 heat range plug, but you shouldn't have to on a stocker.
Pipe, gearing, jetting, kart free-ness, so much more, affects temps in an air cooled engine like these.



-----
?Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Each heat range in the Denso plug line drops the cht 10-15*F. Ie, if you're running the typical Autolite 411 equivalent in Denso, it's an ND W24 FS-U plug. Going to one step colder heat range plug (ND W 27 FS-U) will pull 10-15* out of the engine -- that'll put you in a bit safer range.
You can go colder yet to a 31 heat range plug, but you shouldn't have to on a stocker.
Pipe, gearing, jetting, kart free-ness, so much more, affects temps in an air cooled engine like these.



-----
?Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
Thanks Brian, that is very useful information!
 
I thought yrs ago that 450 degrees was where you wanted to be on engine temp during the race.
From what everyone is telling me, 450° is not sustainable over a period of time, as it well wear out the motor quicker. Furthermore, I'm told the proper range is 410°. to 425° for these flatheads to make the most power.
Can I get a confirmation on this?
 

jglenn

old member
as noted make sure your coil vane is in. what size track and how hard are you turning the engine.. I usually turned my stock heavy engines around 6900 on 1/5 to 1/4 mile tracks. smaller I might turn it a bit harder..

I probably as in the minority but my dyno tests always showed more power around 375 on head temps. I almost never got over 400 degrees and ran a 48-50 jet all year long. these were with I/C engines and the Bu8H plug.. timing was generally a static 29 degrees other than a few engines which liked a lot less.
 
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