# honda gx160 engine



## bluejean (Mar 26, 2020)

I have a Honda gx160 engine and will only run on choke. I replaced the carb set the governor, and stills only runs on choke. Help!


----------



## paulr44 (Oct 14, 2008)

Did you use an OEM carb or an online x-brand? That alone could be the issue.
You're basically describing fuel starvation and/or vacuum leak, but it could be the intake valve isn't seating properly as well or even a cracked cylinder head.

Does it run fine for a few seconds then require choke? If so, the tank screen or fuel line could be restricted and it leans out once the feed tube is evacuated of raw gas and doing it's emulsion thing.
Vacuum leak testing: while it's running, spray some carb. cleaner around the insulator/manifold area, looking for a change in RPM. Careful not to hit the throttle shaft area, that will usually get a response which is a false-positive.

Unlikely but a valve issue could be the cause. If you get nowhere with the above, start by checking valve lash. Testing compression on an engine with a compression release isn't quite accurate, but typically you'd expect to see 60-80 lbs.


----------



## bluejean (Mar 26, 2020)

No only runs on choke. It did this on the original and new carb. It will die off choke. I have no backfiring. Are these heads known to crack?


----------



## Milton Fox Racing (May 27, 2014)

How long are you letting it run before you turn off (reduce) the choke or it runs through its auto adjustment phase?


----------



## bluejean (Mar 26, 2020)

I let it warm up, but it will die right away when I take it off of choke. I also adjusted the valves, its not a genuine Honda engine. It came off of a Coleman minibike.


----------



## Milton Fox Racing (May 27, 2014)

Did you change the spark plug or ignition? How about the plug wire is it moving with the chock and grounding out somewhere?


----------



## bluejean (Mar 26, 2020)

Milton Fox Racing said:


> Did you change the spark plug or ignition? How about the plug wire is it moving with the chock and grounding out somewhere?
> [/QUO


----------



## bluejean (Mar 26, 2020)

Nope. I'm going to try a different gas tank and fuel line.


----------



## bluejean (Mar 26, 2020)

I changed the fuel line and tank again it runs on choke but dies off of choke.


----------



## paulr44 (Oct 14, 2008)

The fact that it does it with the orig. and replacement carb. is why I pointed you away from the carb. itself - like a vacuum leak or other problem. Symptom vs. disease.


----------



## bluejean (Mar 26, 2020)

paulr44 said:


> The fact that it does it with the orig. and replacement carb. is why I pointed you away from the carb. itself - like a vacuum leak or other problem. Symptom vs. disease.


If I do a leakdown test to see if the valves are seating, how much pressure do I test it with?


----------



## paulr44 (Oct 14, 2008)

Any typical 4-stroke engine should not see more than a 10% loss. Usually you use 100psi air in, so anything below 90psi is NG. But, a compression test with most smaller engines such as this that have a compression release should see about 60-80psi comp. such as B&S engines.
See pic, Honda cites 85psi min.
Valve lash is .006" and .008' +/- .001"
Did you check for a vac. leak with brake clean spray?


----------



## bluejean (Mar 26, 2020)

Yes I used brake cleaner with the straw. Kept away from the throttle shaft from having a false reading. Sprayed it around gaskets and insulator, and engine revved. I got a new one coming.


----------



## paulr44 (Oct 14, 2008)

Important: While the rubber-coated metal intake plate _looks _like it should go between the insulator and carb., it doesn't. It goes on the choke side.


----------



## bluejean (Mar 26, 2020)

Yes I used brake cleaner with the straw. Kept away from the throttle shaft from having a false reading. Sprayed it around gaskets and insulator, and engine revved. I got a new one coming.


paulr44 said:


> Important: While the rubber-coated metal intake plate _looks _like it should go between the insulator and carb., it doesn't. It goes on the choke side.


Ok, now that new isolator and gaskets are in. It will run out of choke, but will die at idle right away. At full throttle (out of choke), It will surge up and down any ideas?


----------



## paulr44 (Oct 14, 2008)

I'm assuming this is with the new carb. The old carb. could have a restriction.
First, how did you come upon the new carb., i.e. did you go by the numbers, or just bought one that's known to fit a GX160? I ask this, as even within the series of a particular Honda engine, the carb. jetting can vary greatly. That's the first thing to address. After that, a vacuum leak may still exist, or it may be a fuel flow problem from the tank.

If the jetting is suspect, usually you'd have to remove both jets to read the number, as Honda usually stamps it in the side of them, above the threads.

Surging could be from a lean condition (fuel delivery or vac. leak), but also you may want to reset the_ governor static setting_. Search this forum you'll find that setting explained.


----------

