Inquiring on racing parts for 12 HP briggs

[MowerJo19]

I can’t find the engine code anywhere on the engine, but I didn’t look on the carb or on the spark plug could it possibly be under the cover.

 

[Mower King]

I'm not sure where they are located on the cover/shroud of a 12 HP but, there are usually 3 lines of #'s stamped on it. You have to look at every square inch of the shroud real good. I guess there could be a tag on the shroud also but, most likely stamped!

 

[MowerJo19]

I'm not sure where they are located on the cover/shroud of a 12 HP but, there are usually 3 lines of #'s stamped on it. You have to look at every square inch of the shroud real good. I guess there could be a tag on the shroud also but, most likely stamped!

All I could find Is Model 281707 Type 041501 Code 90032731

 

[StarTech]

That is what they are needing. 281707-0415-01 Manufactured March 27, 1990 in plant 31

 

[MowerJo19]

That is what they are needing. 281707-0415-01 Manufactured March 27, 1990 in plant 31

Yeah, but I can't figure out the model is it a model 19 or 28?

 

[bertsmobile1]

Measure the bore & stroke
Big difference between 19 Cu inches and 28 Cu inches
Within engine types most blower housings are interchangable but usually not between OHV & SV engines so you can never believe the numbers on an engine you did not buy new.

 

[StarTech]

That is what they are needing. 281707-0415-01 Manufactured March 27, 1990 in plant 31

The first two digits is the cu in of the engine so this one is 28 cu in.

 

[bertsmobile1]

The first two digits is the cu in of the engine so this one is 28 cu in.

provided the blower housing is the one the engine left the plant with .
Been caught out by swapped housings on more than one occasions

 

[MowerJo19]

I kinda wonder if a 34mm Mikuni from go power sports would bolt up to it...

 

[Hammermechanicman]

Hot rodding a 12hp flat head is essentially the same as the 5hp used for years in WKA racing. Installing a larger carb without a cam change is uselesss. The 5hp can run at 6000 RPM with the stock rod. The 12hp can't. As far as i know there is no AM rods or cams for the 12hp. Things that can be done to the 12hp is:
Using offset key to advance timing
Mill head and relieve for valves
Deck block for zero piston popup
Grind easy spin bump off the cam
Valve lash to .003
Remove the govenor at your own risk.
If the compression is raised by removing the easy spin bump on the cam and the head is milled the electric started probably won't be able to crank the enine iver.