Tip For A Small Engine That Won't Start

[raffy]

We have a Craftsman 26" rototiller (bought new in 1997, I think, so it's about 14 years old) with a 5 HP Briggs and Stratton horizontal shaft engine that would not start a couple of days ago. This thing has a manual choke. Pulled and pulled and pulled, and still no start. I tried all different choke settings, and it would not kick. So I removed the spark plug and noted that it was dry, with the plug itself looking good, very little wear on the electrodes. So I poured in a small amount of gas into the spark plug hole, replaced the plug, pulled a couple of times and then it kicked for a second or so. OK, so it's obviously not getting gas into the cylinder, which probably means a carburetor problem. So I removed the air filter and sprayed some Amsoil Power Foam carb cleaner into the throat. Pulled again. Again it kicks but no start. I figured the carb was bad, so I decided to leave it and started looking online for a new carb.

Fast forward to the next day. I decided to go out and give the tiller another whirl. Guess what? It fired right up! Obviously the carb cleaner I put in there soaked for a while and cleaned out the carb overnight! So if you have a no start condition caused by a faulty carburetor, give it a few shots of carb cleaner (and Amsoil Power Foam is a good one), pull the starter cord a few times to suck it through, and let it sit overnight if it doesn't start. Then try again the next day and it just might fire up for you!

I always use some kind of fuel stabilizer with all the gas I put in my small engine equipment, but the tiller apparently does not get enough use to keep the gas fresh even with stabilizer. I guess I'll start siphoning out the gas and running it dry if it is not going to be used for a long while.

 

[eljefino]

 

[tommygunn]

I usually "fog" my small engines - even car engines with MMO or Seafoam before storage......sounds like the Power Foam worked about the same as the MMO does.......only, the MMO being a preventative, I add it to the gas and oil BEFORE storage.....not after storage, when I want the engine to work

Surely MMO, or even the Power Foam itself would have been better in the spark plug holes rather than straight gas though; but glad to hear your success story and that you got it running.

 

[ARCOgraphite]

I prefer to keep tcw3 oiled gas in the carb rather than dry to prevent aluminum rust - but both dry or wet storage seems to work for guys here if you run the engine at least once a year and get fresh gas in there.

 

[Donald]

Glad you got the engine started. But I would assume in most cases, when its a carb problem, its either in the float needle valve or jet, neither of which will see much action by spraying any cleaner down the throat of the carb.

 

[GMBoy]

I would still take the carb off and do a good soak if you have the time. That way you'll be able to take it apart and clean in the small passageways.

 

[GMBoy]

Originally Posted By: Donald
Glad you got the engine started. But I would assume in most cases, when its a carb problem, its either in the float needle valve or jet, neither of which will see much action by spraying any cleaner down the throat of the carb.



Right. That's why I was recommending the real cleaning by disassembly.

 

[Nick R]

I've had to pull the carb bowl off our 675 Briggs a few times to clean dirt out of it that plug up the jet. At least it's an easy, quick fix. Still annoying though.

 

[Donald]

Originally Posted By: GMBoy
Originally Posted By: Donald
Glad you got the engine started. But I would assume in most cases, when its a carb problem, its either in the float needle valve or jet, neither of which will see much action by spraying any cleaner down the throat of the carb.



Right. That's why I was recommending the real cleaning by disassembly.


As a somewhat quick fix, you can pull the fuel bowl, remove the float and needle valve and spray some carb cleaner via straw into the fuel inlet and jet. This would save removing the carb from the engine.

 

[Donald]

Originally Posted By: ARCOgraphite
I prefer to keep tcw3 oiled gas in the carb rather than dry to prevent aluminum rust - but both dry or wet storage seems to work for guys here if you run the engine at least once a year and get fresh gas in there.


I did this recently with snowblower, ran the gas tank dry, drained fuel bowl then added maybe 1 pt of 2 cycle fuel.

Maybe the best would be to use some of the "pure gas" one can buy at OPE dealers. its pure gas, not E10. Use it to make 2 cycle fuel.

 

[raffy]

Thank for all the comments and advice! I may go ahead and remove the carb for cleaning in the fall or winter after the garden peters out for this season. But then again, after the Power Foam treatment it seems to be running just fine and the engine seems to be putting out plenty of power while tilling. You know what ol' Murphy says: never mess with a working system!

Looking at the Briggs and Stratton Single Cylinder L Head engine repair manual though, it seems that this carburetor does not have a float. It is mounted directly to the fuel tank and has a pickup that extends into the tank. It has a main jet and a choke mechanism and the idle and mixture screws and that's about it. So I think the Power Foam solved whatever was preventing fuel flow into the carb. It seems that, looking at the diagram, most of the working components of the carb lie downstream of the throat. It is quite a bit different from the carbs on my lawnmowers and generator, which definitely do have floats.

I did go ahead and add a small amount, maybe a tablespoon or so, of MMO to the gas currently in the tank. Tommygunn mentioned "fogging" the engine with MMO or Seafoam. What exactly does that involve? Do you run the engine for a bit to distribute the MMO into the cylinder, or squirt it directly into the cylinder through the spark plug hole before storage?

 

[Donald]

You can get fogging oil at boat dealers. You typically spray it down the carb throat until the engine stalls at fast idle. On V8 engines one needs two cans going at once. You can also spray it down the spark plug hole but that does not coat the intake manifold (on a boat engine). Fogging oil is an oil with a "tacky" component. So when it hits the cylinder and covers it, it will not run down and puddle on top of the piston.

Forget about MMO, it might have been useful in the 60s, but there are far better products now. For fuel, blue StaBil or Startron gas treatment. Both are sold at Walmart.

 

[FNFAL308]

You got lucky, these carbs can be a real PITA and the fact that you got this one to run w/out taking it apart is simply a roll of the dice..

More times then not this is simply not the case..
Take the carb/tank assy off, clean everything including the fuel pick-up inside the tank. You will see the "bowl" inside the tank when you get it apart and these are often full of nasties.. Tank itself may be rusted (seen it many times) so plan on having some nuts and bolts you can throw in there and toss around to clean it up..
Get the Mod/Type/Code from your engine and hit your local small eng shop for a diaphragm kit. Going through the trouble of removing the carb/tank and not replacing the diagram is a BIG mistake.

Pay particular attention to the linkage and gov assy, this parts trips a LOT of peeps up..

 

[raffy]

I've been starting and running this tiller's engine every day this week so far to keep it honest and make sure that getting it to start was not just a fluke. So far, so good and yesterday it started on the first pull. So I think the Power Foam treatment followed by adding some MMO to the gas really has helped a lot.

FNFAL's suggestions to clean the tank and replace the diaphragm are good ones - the diaphragm has already been replaced once and might be due again.

 

[2cool]

Is this a 4-stroke engine?

 

[FNFAL308]

Originally Posted By: 2cool
Is this a 4-stroke engine?


YES...

Good deal RAFFY..
I'm glad it's running well for you..

 

[andyd]

I used to have to mess with carbs evry spring to get my OPE running. Since I started adding MMO to the tank at evry fillup, Way less carb troubles. I can only get 87 octane with 10% ethanol Sometimes you can clean out a carb by shooting cleaner into to keep it running. After a few minutes the cab would clean out well enough to run on gas, Then I would add some Chen-tool B12 to the gas for additional cleaning. The idea of letting it soak over night sounda like a good 'un too.

 

[raffy]

Interesting point about the gas with 10% ethanol. When I bought a Honda generator from Mayberry's, they strongly recommended using 89 or higher octane gasoline. Their view was that this gas had less ethanol in it and would therefore be less troublesome to carbs. After this episode with the tiller, I have just about decided I will use 89 or maybe even 91 octane premium gas for all our OPE, after I use my current supply of 87.

Any info on whether or not 89 or 91 gas is better for OPE carbs than the 87 stuff?

And yes, the tiller engine is a 4-stroke, 5 HP Briggs and Stratton with a horizontal shaft and manual choke.