# Engine surging - getting better or worse?



## jakew8 (Jan 3, 2019)

After just one season, my HS720 engine was surging without the choke. I guess I left E10 fuel in the engine for too long into the spring last year. A local Honda repair shop suggested trying Seafoam for now (since they're backed up with repairs).

So I put a couple of ounces of Seafoam into the tank, ran it for a few minutes, and waited a week. After a week, the engine still surges without the choke, but it surges more frequently. If there were roughly 60 surges per minute before, there are 120 now. I can still use the choke to even out the mix. 

My question: Does the increased surging frequency without the choke mean that the Seafoam helped the fuel system, or made it worse?


----------



## Toro-8-2-4 (Dec 28, 2013)

It probably loosened some crud that effectively made the problem worse.



You need to either take the carb off and give it a good cleaning or buy an new carb. Check out ebay for a new carb and i bet it will be half or less than what the dealer will charge you for cleaning the one you have now.


----------



## tdipaul (Jul 11, 2015)

.

The dealership was brushing it off because they are busy. 

IMO Seafoam is not the "mechanic-in-a-can" like lots of people claim it to be. Ive soaked individual carb parts in it for days and it did nothing, nada. 

Its time to drain the gas, remove the carb float bowl and clean it, and then remove the main jet and run a small wire through it. 

start over with fresh fuel in the tank and dump the old in the car

the first time is the hardest but there's nothing more rewarding than fixing it yourself

those beers are the best

remove #6 with a 10mm box end wrench, tap on the bowl to dislodge it. Try to not disturb #1.

Then use a very good properly sized screwdriver to remove #30. The size of the driver and applying firm pressure is key so as not to slip and strip it. #11 might fall out and thats okay as long as it is put back the same way




#30



.


----------



## jsup (Nov 19, 2017)

Make sure there's no vacuum leaks. Check the gasket, spray carb cleaner around the carb, see if it clears up.


Check the spring on the governor. It goes from the governor rod to the carb throttle, next to or over the linkage.


Tighten the screws that hold the carb in place, make sure they are good and tight.


If you are running the carb "naked" without the cover on it, put the cover back on.


If none of that works, go to Amazon and buy a $15 carb, replace it, and never look back.


----------



## tdipaul (Jul 11, 2015)

. 

Yes, but if he has the ability to swap out a carb he should try cleaning it first. It is much easier because there's no messing around with the fragile linkage rods and springs that, if disturbed, can really throw things off. 

If the carb is super dirty and corroded then a new carb is a must but since its getting enough fuel to run, the float system is working. The machine is only a year old so it cant be that bad 

.


----------



## tdipaul (Jul 11, 2015)

.

edit

you might not even need to remove #30

Just remove the float bowl and run the wire through it with it still in the carb!

.


----------



## tabora (Mar 1, 2017)

Surging sounds like either a partially blocked main jet or some crud keeping the float valve from seating properly. Both problems can cause surging, but for different reasons. Water in the bowl can also simulate a partially blocked main jet.


----------



## Toro-8-2-4 (Dec 28, 2013)

If JSUP is right and a new carb is $15 it is no brainer. Get one that comes with new gaskets. Sometimes they do and sometimes they do not. You can clean the carb but sometimes it does not get it clean enough and you have to repeat it. Maybe more than once. Unless you have a good ultrasonic tank to soak it in with the sonics and heat on. You dont need heat but it helps. The tiny inexpensive type for cleaning jewelry are not that good. I tried one once and it did not work.


I would remove the idle and main jets. It gives you the best chance of success. As suggested above you do need a very good fitting flat blade screw driver to remove the main jet (30). It is brass and you can strip it very easily if you are not careful. I have ground down the edges of a good flat bade screw driver so that I can make the most contact with the jet slot and have it so it just fits into the bore. In other words, use the largest screw driver you can.


Another approach is to soak it in Kroil for a few hours then clean it in carb cleaner and blow it out with air. I have found the Kroil is an excellent solvent and I have had good success using it when just carb cleaner alone did not work.
Also, make sure you remove item 11. It is the emulsion tube and it has small holes in it that run perpendicular to the main jet hole. You want to make sure that they do not get plugged. by removing it, It will also help you better clean the passage way to the idle jets.


Cleaning it is not hard but very time consuming. It comes down to how much do you value your time. Good luck and a very solvable problem.


----------



## orangputeh (Nov 24, 2016)

i wouldn't buy a new carb for it since this machine is fairly new.

have run into this problem dozens of times and the first thing I would do is drain gas, remove bowl.get some carb cleaner and push straw up pick up tube and spray. follow with compressed air if you have it. I use a can ofcompressed air people use to clean their keyboards with. now i have a compressor to do that.

this usually works for me. otherwise the next stepwould be to take out the jets and clean them and/or spray all the passages out.

replace gas with E Free gas ( ethanol free gas )or gas treated with Stabil and /or Seafoam.Do not use toomuch Seafoam or else you will damage the O rings .


----------



## jsup (Nov 19, 2017)

orangputeh said:


> i wouldn't buy a new carb for it since this machine is fairly new.
> 
> have run into this problem dozens of times and the first thing I would do is drain gas, remove bowl.get some carb cleaner and push straw up pick up tube and spray. follow with compressed air if you have it. I use a can ofcompressed air people use to clean their keyboards with. now i have a compressor to do that.
> 
> ...





I do the same thing, all that can be done without taking it off the machine. When it gets to the point of taking it off the machine, new carb.


----------

