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

Helmet Painter / 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?
 

meracer9

Site Supporter
Try the NGK BU8H plug.. We tend to run them in the hot summer months and it does drop the temps.
 
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 ?
 

CarlsonMotorsports

Site Supporter
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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