Horse power on 735cc engines?

[7394]

If my memory is any good, those where the engines which got Briggs in trouble and started the questionable hp lawsuits.

IIRC, Briggs was ordered to pay some money to owners, who bought the machines in the suit..

 

[SamB]

Kohler did the same thing with the CH18-20-22 engines. The 18 had a screw next to the throttle butterfly lever that limited it to only opening halfway. the 20 had the screw removed which allowed full throttle plate movement, and then the 22 added spark advance smart spark.

That's interesting. Side note, back in the late 1960's, Pontiac did the very same thing to the Firebird's 4 barrel carbs so the GTO with the same engine/transmission as the Firebird, would be a bit faster. They did it with the linkage to the rear barrels.

 

[Hammermechanicman]

Back in the 80's they were putting BOP engines in chevy cars and then they put chevy engines in BOP cars. My mother had a Bonneville with a 400 Chevy motor in it and a friend had a monte carlo with a 3.8 BOP engine. Fun getting the right oil filter.

 

[7394]

Back in the 80's they were putting BOP engines in chevy cars and then they put chevy engines in BOP cars.

I remember that.....

 

[Ken_L]

That's interesting. Side note, back in the late 1960's, Pontiac did the very same thing to the Firebird's 4 barrel carbs so the GTO with the same engine/transmission as the Firebird, would be a bit faster. They did it with the linkage to the rear barrels.

Little more to it than just the carb linkage. 400CI Pontiac engines 1967 and up used the same block, but offered some different HP ratings for GTO, Firebirds and other models - such as HO and Ram Air type optional engines. All had 4 barrel Quadrajet carbs but used higher performance heads, intake manifolds, exhaust manifolds, and cam shafts, etc. May all look the same on the outside, but they are different.

 

[Freddie21]

This brings up a question I've had. What are typical jet sizes for Kohler and Briggs single lung engines. I have carbs that all look the same but some will surge and need the jet opened. I increase till it levels out, but would like to know what good sizes are.

 

[Rivets]

I start will a #80 drill and work up. When I have to punch a jet the largest drill size I use is a #77 drill. That would be .018“. I do remember using a number drill #76, .020“, but I found out the hard way that it may be too much. Now I only do this if I have a spare jet on hand. I should add that the material used in today’s jets is not the same as when I started in the ‘70’s. I’ve found some to be harder and some softer. Anyone who attends punching jet nowadays should be prepared to purchase a new jet or carb before attempting to do this. Voice of experience.

 

[7394]

Anyone who attends punching jet nowadays should be prepared to purchase a new jet or carb before attempting to do this. Voice of experience.

Thanks Rivets- Good advice.

 

[edporch]

I read this thread and am getting more confused.
Any expert info on this engine would be appreciated.

I have a 725cc Kohler on my 2008 727T6 Grasshopper that is supposedly 27hp .
DISPL (CC) 725
MODEL NO. CH740S
SPEC NO. CH740-0096
SERIAL NO. 371990010x
BUILD DATE 07/18/2007

IS it really 27hp, and can I re-jet or tweak it to get more hp?