I dont have much experiance with these Briggs and Straton motors on my reel lawn mower but here is my question.  I t ran fine last year and I use it this year and the idle goes up and down and not steady like it used to be.  I changed spark plug and air filter and drained old gas out and put in new gas and nothing helps. WTF could it be? trash in the carb?  I am out if ideas and that is the oly other thing I think it could be.   

If the actual idle goes up and down (meaning low engine speed) it is typically time for a carb overhaul or sometime cheaper to buy a new carb....

There is an idle circuit on the Pulsajet carb that is really puny and they get plugged quite easily. Have you tried putting your hand over the air inlet to the carburetor partially blocking some air flow? you can verify if it is rich or lean by this method, if it is lean (engine speeds up when partially blocked) then I would say it's carb time, if it chokes out or slows, look for a blocked air filter, partially blocked venturi, or improper plug gap (too wide)...

If it is not a Pulsajet (identifiable by the location of the fuel tank, Pulsajets are mounted to the top of the tank) then I would say potential needle and seat/float problem...(Pulsajets do not have floats)...

Also look for a base gasket leak if it ever backfired upon start up....

And yes, I have spent several years working on small engines....

GT

My experience with Briggs and Strap-on engines is pretty much the same. Soft taps on the carb with a brass or rubber mallet while running usually solved the issue (New gas, old gas caused most of the issues).

Beyond that.......then the sledgehammer came out...........I've never been known for patience.........

I got a mower here, free if you want it.......I bought a Honda..........

Ray

A Honda Ray? Least you could of done was to give TDR a call, Im sure they have some Suzuki ones..... 

This is really going to show my redneckness, but se la vi....

I have a Honda mower also....But I did not exactly "pay for it".


Soooo I am at the transfer station (big word for dump) and dropping off a bunch of scrap metal from a job, and this dude pulls up in a brand new Dodge diesel 4X4, backs up to the metal pile, unloads what looks to be a brand new Honda mower, rear bagger front drive stainless deck, nicer than anything I have ever owned, then drives off.....

So here I am, thinking HMMMMMMM 

I walk over to it, grab the handle and give it a pull, she has compression....Hmmmmm

So screw it, I figure I will thow it in the back of the truck, worst case, I have to pay to drop it off again...

Get it home, pour some oil and gas in it (empty) and pull the string......It fires up and sputters and gasps and is smoking like crazy...

I shut it off, pull the air filter cover and oil comes oozing out of the filter....I go grab the air filter from my generator (ironically the correct one) and throw it in, fire it again and Viola!!!!! runs perfect, cuts perfect, moves with the front drive...

I am in it for 1 1/2 quarts of 30 wt, an air filter and a gas cap (it was missing)....

I know....I am truly showing my white trashness, but hey, I have a running lawn mower. Horizonjet does not....

GT

one mans trash is another mans mower...

Thanks for all the ideas'.. I will give them a try later and let ya know what works best. It has a throttle control and manual  choke.   You cam see  a spring  on top  of carb that  goes to engine  and when  this pulls it revs engine. The carb is on top.of tank.

Thanks for all the ideas'.. I will give them a try later and let ya know what works best. It has a throttle control and manual  choke.   You cam see  a spring  on top  of carb that  goes to engine  and when  this pulls it revs engine. The carb is on top.of tank.

Pulse-A-Jet...

http://outdoorpowerinfo.com/repairs/briggs_pulsa-jet_horiz_adj.asp


The spring comes from the governer...

   I call BS on this !!  there is NO grass in AZ.   What are you doing with that mower ?  Leveling off the gravel in your yard ?  Grinding up a cactus ?  Killing cats ??   

To Funny!      Cats move too dam fast or they  would be far game.  Gravel is more my speed.  Come to find out there is a little tiny air/fuel mixture screw on the bottom of the carb. in the idle circuit i believe and it had vibrated all the way in and caused the whole problem.  I turned out 2 1/4 turns and lock tited it in there and its good as new.