Motorcycles, Snowmobiles, Go-Carts, ATV's and Golf Carts - Stalling on acceleration

My son has a 1974 5 hp Briggs engine from a
roto-tiller on a go kart. It idles fine and
runs at high speed fine. But, it stalls when
you speed up the engine. If you are careful
how you accelerate it it will make the transition.
If you let up on it and accelerate it again it
dies over 90% of the time. The carb has been
cleaned and the diaphram and spring replaced.
What needs to be done on this engine?
He has another 5 hp Briggs engine that does the
same thing but not as bad as this one.

Hello: den942

Since your topic was orginally posted in the small engine forum and we now have a pro on the topic of go-carts, I moved your topic here.

Now the "My Two Cents." part :)

Roto-tillers are not the same as go-carts. Go carts have different engine loads applied to them and the engine has to have the flywheel effect to handle the load demands.

The carbs are not exactly the same. Each may provide slightly different fuel amounts for the engine demands of each different type of equipment.

The same applies to the governors etc.

I'll let the real professional in this forum topic provide you with expert advice.

Regards & Good Luck,
Tom_B
Small Engine Forum Host & Moderator
"Accurate Power Equipment Company"
Small Engine Diagnostics Services and Repair.

During installations of some parts which may not fit exactly perfect, it may be necessary to apply "BRUTE" force in order to compel compliance.....:D....:D {....just humor folks...:) }

Personal Quote:
"If it ain't already broke, don't fix it, tinker with it or $#@&*&%$#@! with it until you do break it!"

I agree with Tom...The carb is probably not the same. You may, however, be able to back out the mixture screw to richen up the fuel ratio, and get by with it. If you do, you may also need to idle the engine up a bit. Let us know if this helps.

Hey den942, a "74 model probably has the sliding barrel choke carb if original and can be made to function well as a go-kart engine. As has been mentioned bringing the adjusting screw out should help feed fuel under a load though idle may be a little rough but the cure for that is what cheese mentioned, idle up a bit. Stock engines really can't be perfect in all phases of operation like nice smooth idle, smooth rapid acceleration, and holding top end without leaning out. These 5HP's were never intended to. Without carb modification all three most often can't happen.
A couple of things you can do with a minimal amount of tools: Remove the half inch nut that removes the adjusting needle, take a look at the screwdriver slot that removes the jet, if its not horizontal file or sand the back side of the jet until when installed the slot is horizontal. Along this line of thought there are two holes behind the jet, with an orfice drill open up the front hole to about .032. This may cause a bit of slight flooding at idle but when you go down on it she will sing and will not lean out when holding top speed. Of course this is most effective when the governor is disabled but one must really watch holding those high RPM's. One other neat note, if you open the hole to about .040-.045 the engine will run on methanol (no more gas) but the governor must really be disabled to reap benefit. With either modification removing the baffle from the carb will make your buddies wonder where you got that engine.....Mike

you might want to insure that the fuel line is absolutely clean and that their isn't any additoinal sediment in the gas tank flowing thoirugh, si that when the additional gas surge is needed for acceleration, the proper mixture and amount is delivered.

Having a gas tank with rust sediment could contribute to this, as I would have suggested first what you already tried.

If for some reason their is a fuel pump or asist mechanism, you would have to look at that. Also, their is probably a carb float that may be cracked or broken which is not letting the proper amount of fuel to be stored in the car. bowl.

:cool: