# small engine help



## brushbuster (Nov 9, 2009)

I have 3.5 horse Honda engine on my cement mixer. one pull starts it right up. it runs for a minute and then sometimes it shuts down. I can pull forever and wont start. come back in a few minutes and it starts back up. Ive done all kinds of things, new plug, new plug wire, new gas filter, new air filter. One thing I have noticed and it seems to work, I can take the air filter off and it will stay running, I put the air filter back on and it will start to shut off, I quickly remove the air filter and it runs until im done mixing.
Any ideas?


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## d_rek (Nov 6, 2013)

brushbuster said:


> I have 3.5 horse Honda engine on my cement mixer. one pull starts it right up. it runs for a minute and then sometimes it shuts down. I can pull forever and wont start. come back in a few minutes and it starts back up. Ive done all kinds of things, new plug, new plug wire, new gas filter, new air filter. One thing I have noticed and it seems to work, I can take the air filter off and it will stay running, I put the air filter back on and it will start to shut off, I quickly remove the air filter and it runs until im done mixing.
> Any ideas?


Sounds like classic gummy carb to me. Possible clogged fuel line. Only reason it stays running with air filter off because it’s getting a little bit extra air without the filter on... but then the filter isn’t on... catch 22. 




Sent from d_mobile


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## d_rek (Nov 6, 2013)

You can pop the carb off (being careful to note how the gaskets go back on) and soak the whole thing in carb cleaner, but the best way to clean it would be in a ultrasonic parts cleaner. 

Also don’t try to force compressed air through the carb. You’re likely to make any clogs worse that way.


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## kroppe (May 7, 2000)

Sounds like a fuel problem. 

If it were mine I would let it run at idle and dose it with carb cleaner a shot or two at a time until the whole can was used. This might take a while. 

Also replace any rubber fuel line that is more than 5 years old. 

Lastly have a close look at choke and throttle plates and mechanisms to be sure they are operating properly.


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## CHASINEYES (Jun 3, 2007)

Sounds like an idle air port might be plugged. If fuel related, a classic flooded condition is come back later after some of the fuel has evaporated from the spark plug or pull the plug and dry it off yourself.

Should be an idle air port somewhere next to the venturi. Try to clean that circuit.


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## shanny28757 (Feb 11, 2006)

This is what I would do. But I’m not a contractor (Not sure if you are or not) so this advice may not work for you. 

Step 1. Sell cement mixer 
Step 2. Rent cement mixer Feom Home Depot $50/day the 2-4 times I’ll need a cement mixer throughout the rest of my life and let them do the maintenance on the machine 

In all seriousness, I’d tear apart the carb and clean the heck out of it. That’s the extent of my small engine repair knowledge though.


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## WALLEYE MIKE (Jan 7, 2001)

d_rek said:


> You can pop the carb off (being careful to note how the gaskets go back on) and soak the whole thing in carb cleaner, but the best way to clean it would be in a ultrasonic parts cleaner.
> 
> Also don’t try to force compressed air through the carb. You’re likely to make any clogs worse that way.


I'd go with that. Daughter had 2 engines with about the same problem. Took carbs to a buddy for ultrasonic cleaning. Cured the problem.


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## Fishndude (Feb 22, 2003)

shanny28757 said:


> This is what I would do. But I’m not a contractor (Not sure if you are or not) so this advice may not work for you.
> 
> Step 1. Sell cement mixer
> Step 2. Rent cement mixer Feom Home Depot $50/day the 2-4 times I’ll need a cement mixer throughout the rest of my life and let them do the maintenance on the machine


My wife and I put in an 800 sq ft patterned paving block patio some years back. We laid the base, and compacted, and put in the large patterns. Then we had to fit the background block in, cutting blocks to fit as we went. It took 2 weekends. I rented a wet saw from Home Depot each weekend, for $60/day. I burned up 3 saw blades that each cost $300 doing the job. Why buy?

Sorry to sidetrack the thread.

I agree with everyone else. Gummed up carb. My son would remove it, clean the ports with thin wire, clean the inside of the bowl, and have it back together in 20 minutes. He's real handy with that stuff.


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## brushbuster (Nov 9, 2009)

I think this was the problem. I replaced a hose that was cracked that led from valve cover plate to the air side of the carb, got it running doused the carb with sea foam, and then added seafoam to the gas. Been running all morning with no issues. Picture of hose won't post. Too big a file I guess


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## brushbuster (Nov 9, 2009)

Well. I may have spoke too soon. Just went to start it to finish my last batch after lunch. Started just fine, one pull, and the shut down. Almost makes me wonder if I have a electrical issue. Switch,coil. I don't know yet.


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## brushbuster (Nov 9, 2009)

Got it fired up again and able to keep it running to finish putting my anchor bolts in. The more I screw with it the more I think it is a gummy carb. The sea foam seems to clean it up enough to keep it running. When I get time I will have to tear into it and cleaner up. Another project.


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## Nuggets (Oct 7, 2017)

Honda has a autochoke system check out this utube video

Sent from my SM-J727T using Michigan Sportsman mobile app


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## So-hooked (Jun 16, 2009)

Gummy carbs had always been my problem with the start issues as described, no matter what is was. 
1oz seafoam per gallon of gas and never any issues for the last 4 years, even if it sits an entire year like my power washer.
Buying my dad and FIL both a gallon tomorrow so I don't have to clean their carbs anymore LOL 
Gift plus an investment for me


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## sparky18181 (Apr 17, 2012)

brushbuster said:


> Got it fired up again and able to keep it running to finish putting my anchor bolts in. The more I screw with it the more I think it is a gummy carb. The sea foam seems to clean it up enough to keep it running. When I get time I will have to tear into it and cleaner up. Another project.


I know it’s not the same but kinda had the same issue with a snowblower. I cleaned it and all the stuff you did. I ended up buying a new carb for like 15-20 bucks and works perfect now.


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## Bandit67 (Nov 10, 2019)

Non ethanol "Recreational fuel" and Sea Foam will keep small engines running great for many years.


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## CHASINEYES (Jun 3, 2007)

Bandit67 said:


> Non ethanol "Recreational fuel" and Sea Foam will keep small engines running great for many years.


Might be what happened to that blow by hose. Wonder what side of the air filter that hose is. Could be particles in the idle circuit. Not part of the fuel system, but blow back from the carb and probably even blow by contains some unburnt ethanol.


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## thumbgoodfisherman (Dec 6, 2005)

brushbuster said:


> I have 3.5 horse Honda engine on my cement mixer. one pull starts it right up. it runs for a minute and then sometimes it shuts down. I can pull forever and wont start. come back in a few minutes and it starts back up. Ive done all kinds of things, new plug, new plug wire, new gas filter, new air filter. One thing I have noticed and it seems to work, I can take the air filter off and it will stay running, I put the air filter back on and it will start to shut off, I quickly remove the air filter and it runs until im done mixing.
> Any ideas?


Sounds like your air filter needs to be blown out or replaced with a new one. Mixing mortar or cement can plug the filter very easily with the dust when your mixing. Had a tamper that started doing the same thing you are saying and you don't think it would get plugged from tamping sand but it did and put a new one on and it ran like a champ. All my concrete power tools have Hondas on them and very air filter sensitive. I replace all filters at the end of my work year. Sounds like what your describing with running then shutting down it is flooding the carb.
I am no mechanic per say I'm just a mason. LOL Good luck.


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## brushbuster (Nov 9, 2009)

Thanks for all the replies guys. I was determined to keep the thing running till I finished my project. I have quite a few cement projects lined up after my garage blocks which is now totally done. Gas engines have always been my curse, I know just enough to keep the things running but not enough to keep my sanity.


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## sherman51 (Oct 28, 2018)

the 1st thing id do is clean the breather. the 2nd thing id do is replace the gas line. a dirty breather could be causing the motor to not be getting enough air. on the older gas lines has an inner liner which separates from using ethanol gas.

get a bottle of gum out complete gas treatment. add about 1/3 of the bottle to 6 gallons of gas. then run it until the cleaner has a chance to work. I had a 03 Taurus that started missing badly when I would start around a car. it ran ok around town. I changed the plugs and wires but it still missed. I added a bottle to a full tank of gas. I used about a half tank of gas and started around a car. it ran great, it didn't miss at all. and never missed again as long as I had the car.


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## d_rek (Nov 6, 2013)

brushbuster said:


> Thanks for all the replies guys. I was determined to keep the thing running till I finished my project. I have quite a few cement projects lined up after my garage blocks which is now totally done. Gas engines have always been my curse, I know just enough to keep the things running but not enough to keep my sanity.


An easy trick is to add a little bit of fuel stabilizer to gas cans and tanks every other time you too them up. That way if they sit for a bit the fuel doesn’t start to go bad. 


Sent from d_mobile


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