Anyone familiar with small engine carbs?

[nine4gmc]

We have a Husky pressure washer with a Briggs and Stratton engine on it, the carb is a 795477 like the picture below. When we pull the string, it fires up but dies immediately. If I sit next to it and pump the primer, it will run a little longer but then dies again pretty fast. We removed the carb and shot carb cleaner through every orifice and it still does the same thing, like it's starving for fuel. I bought it used(like new) a year ago and all I did was dump out the old fuel, fill it up with new and clean the spark plug when I got it and it worked fine for the few times I used it. We ran it out of gas and stored it for the winter, now I'm not able to start it again. any ideas or recommendations?

TIA

 

[AndyCBR]

We have a Husky pressure washer with a Briggs and Stratton engine on it, the carb is a 795477 like the picture below. When we pull the string, it fires up but dies immediately. If I sit next to it and pump the primer, it will run a little longer but then dies again pretty fast. We removed the carb and shot carb cleaner through every orifice and it still does the same thing, like it's starving for fuel. I bought it used(like new) a year ago and all I did was dump out the old fuel, fill it up with new and clean the spark plug when I got it and it worked fine for the few times I used it. We ran it out of gas and stored it for the winter, now I'm not able to start it again. any ideas or recommendations?

TIA

My experience with these small carbs that act that way is the diaphragm has gotten stiff and will no longer pump fuel with the pressure pulse from the cylinder.

I have had several Echo weed eaters/edgers that act this way when they get to 5-7 years old. The constant contact with fuel hardens the diaphragm and they won't deliver fuel anymore.

Often, it is just a bit more money to get an entire carburetor assembly rather than a rebuild kit. Depending on how handy you are, how much you like to tinker with small carb parts, and how much your time is worth will decide whether or not you get the kit or the carb assembly.

Hope this helps...

 

[ron in sc]

Make sure the primer and hoses are not leaking, they often leak and fail if you use fuel with ethonal. use only 100% gasoline.

 

[Show7d3]

That style carb generally sells for $25-$30 and comes with a new diaphragm. You could try cleaning your carb and replacing the diaphragm.

 

[DenisG]

I have a similar carburetor on a Brute pressure washer that I'm fixing. It has a 10T502 5HP B&S engine. If yours has a plastic intake manifold, check that the manifold isn't cracked. Mine had a cracked manifold.

 

[tightwad_wrencher]

I've had fuel tanks create a vacuum and not vent. Causing fuel to not reach the carb.

 

[redmondjp]

You can buy that carburetor new for something like $25 on Amazon. But I'd try replacing the diaphragm as noted above (about $7 at big box store) first.

Then, go to www.pure-gas.org and find a station that sells alcohol-free gas and use only that. I have been doing so for the past two years and it is simply amazing to see what a difference it makes.

Two recent examples: Briggs Vanguard 18HP twin on a pressure washer, hadn't been used for almost two years, with alcohol-free gas left in it. Battery was bad, so the starter didn't even turn it over. I was crouched down over it, and gave the starter rope (18HP twin, not easy to pull-start) a half-pull just to verify that the engine wasn't locked. It started on that half of a pull (had to feather the choke a bit, but I couldn't even believe it)!

Then, same deal with an 8HP chipper/shredder that hadn't ran in about a year. Started on the second pull. No way no how this would have ever happened with 1+ year-old E10 pump gas in there. I would have spent an hour taking the carb apart and scraping all of the gum and corrosion out of it instead.

Yes, E0 costs a bit more per gallon, but when you don't have to fuss with your equipment for hours every season, it is well worth it.

 

[bassbone52]

"Then, go to www.pure-gas.org and find a station that sells alcohol-free gas and use only that. I have been doing so for the past two years and it is simply amazing to see what a difference it makes."


^^^^^THIS!

My example: Stihl straight shaft string trimmer. Would not accelerate or idle worth a damn. Got a new OEM carb for $18 shipped and started running 91 octane no ethanol gas. Starts on first pull. Idles perfectly and runs like new. Keep the ethanol out of your fuel on these small two-stroke engines!!!

 

[nine4gmc]

Yeah, I found a carb for about $21 shipped but wanted to post and see if it may be something I could do without replacing a part. I know the hoses are not leaking, not sure about the intake being plastic or not so I will check it out along with the gas tank vent and diaphragm before ordering a new carb. Thanks for the advice and replies!

 

[bobcatdan]

If the carb has any adjustment, many new ones don't. Back the main screw just about all the way out and try to start it. If it starts then try adjusting it back in to a correct setting. If the jet is blocked at, this clear it out. I've done it many times and it worked like a charm.

 

[laser3kw]

Before you get to far, check the fuel flow through the fuel line. It should come out like a small fire hose. I had a pressure washer similar to yours acting up. It would start hard and die a couple of minutes under load. It turned out to be a in tank fuel filter that closed up under suction. Took it out and put a standard inline filter and fixed it.
Just to test, by pass the tank and feed the motor off a separate fuel tank.

 

[wafrederick]

Make sure the gas is not E85,Lucas does have an additive out now to put in E85 for small engine and other applications.

 

[nine4gmc]

Good info, I didn't check the fuel filter or hose and didn't think to check the gas station if its e85 or not but I get it at the same place every time so I'll check next time I pass.

 

[jkwilson]

Make sure the gas is not E85,Lucas does have an additive out now to put in E85 for small engine and other applications.

Can't imagine there is anything you could add to E85 except 15 gallons of straight gas to make it fit to burn in a small engine.

 

[TheEquineFencer]

The carb I just replaced is nothing like what you have, but here's how I looked at cleaning and repairing the one I had. A new one local was about $60, at kit was a lot less. If I took it apart and tried to rebuild it I'd have an hour or so in it screwing around with it. If I just replaced it and was done with it, I was done. If rebuilding it worked I'd be about $30-$40 ahead money wise, but I'd have 1-2 hours in it. If I just replaced it I'd have 20-30 Minutes in it. I opted to replace it. It cranked on the first pull after that and runs fine. Those plastic carbs can warp and have an air leak, been there, chased that gremlin before too.

87 octane or better gas and Sta-Bil is a good friend to have in the tank IMHO.

 

[Outlawmws]

I've had fuel tanks create a vacuum and not vent. Causing fuel to not reach the carb.

This is an easy quick check to make: leave the cap loose and see if it runs then...

 

[stihlntime]

I would take a torch tip cleaner and run it thru every orifice. Replace the diaphragm as other's have mentioned when reinstalling make sure you don't have an air leak caused by a bad intake gasket. Take your plug out and make sure its not fouled or wet from flooding. I usually blow out the cylinder with compressed air. Run 91 octane no ethanol fuel. We put Briggs and Stratton FUEl treatment in the tank of every mower/trimmer/saw that leaves the shop. We've tried all the additives and we get the best results from FUEL.

 

[Lx460]

Replace the carburetor. You will waste more in time and frustration than it is worth screwing with it, believe me.

 

[Wakefield]

A couple years ago someone had a new budget mower with a "Classic" style Briggs with a plastic carb on it new out of the carton-my 40+ year old series 92,000 with the pot metal "PulsaJet" carb (choke plate modified with holes bored in it) and a replaced pointless ignition device (made in Germany) outpowered it in heavy grass (I don't think the new one even had a speed control on it)
I wish Briggs would build something to go one on one with the cheaper homeowner Honda mower engine and also something to compete with the Pro quality Kawasaki lawnmower engine. I take it the Intek "Pro" and "Edge" models are gone? Did they ever solve the head gasket weakness?

 

[Wakefield]

If the engine had a float carb with a fuel line going to it instead of the suction carb sitting on top the tank it would be good to put a fuel shut off valve and a small fuel filter inline to the carb. I believe I heard that the small orange colored filters are for gravity feed systems. Fine screen mesh inside?

 

[wafrederick]

Can't imagine there is anything you could add to E85 except 15 gallons of straight gas to make it fit to burn in a small engine.

This is the additive Lucas sells, http://lucasoil.com/products/fuel-treatments/safeguard-ethanol-fuel-conditioner-with-stabilizers