Newbie looking for help with Honda GX240 that won't run

[PDX Man]

I am pretty inexperienced with engines, but I'm trying to fix my splitter's GX240 myself anyway. I've tried the easy stuff I can think of and am looking for ideas on what could be wrong and what to try next.

The background: It was running OK, maybe a bit hard to start, but it ran OK. Then it started stalling out when running. I could start it and it would die in a few minutes. Then it just would start with choke, but die as soon as the choke was opened.

I've disconnected the oil shutdown, so it isn't that. I've tried loosening the fuel cap to see if the vent was blocked. I've tried removing the air filter to make sure it isn't a clogged air filter. I've replaced the spark plug, the fuel filter and fuel line. I got a new chinese carb and tried that. It behaves pretty much the same. I'm not sure if those carbs are supposed to come properly adjusted. I saw reviews of the carbs on amazon that say they just bolted the carb on and it worked, so I'm assuming they come adjusted at least approximately. And it behaves pretty much like the original carb, so I'm thinking it is not the carb.

I've noticed now that it will actually run rough for a while if the throttle is set to idle, but it dies after a bit or immediately if the throttle is opened up at all.

I'd appreciate any ideas on what could be wrong and what to try next. Thanks in advance.

If it helps, I've put up some videos on youtube of how it is running now with the original carb and the new carb.

This one is it running with the original carb:

This is with the new carb:

https://www.youtube.com/watch?v=74qYKU7y6-w&feature=youtu.be

 

[Fish]

Open the drain on the bottom of the bowl, into a can, let it dribble a while.
See if the flow is constant, consistant..

 

[Fish]

Also, check your valve clearances.

 

[bill saf]

Im with fish on the no gas. but I would pull the gas tank clean screen and pull the fan shroud and clean the coil and re-gap clean mags in flywheel any rust will give you low spark. and one other thing you cant just unplug the yellow wire from the low oil unit unplug the lil silver box take it out of line to test. I have found that that box when it starts to go bad and it gets worm will ground the coil. DID you replace the carb gashets or reuse and look at the plastic carb insulator for a crack

 

[CR888]

^^^^it only takes a small leak from the carb/intake gaskets to give you trouble. I'd put new gaskets from the carb to the intake.

 

[bill saf]

Here is the service manual it has all the spec's hope it helps

 

[PDX Man]

Im with fish on the no gas. but I would pull the gas tank clean screen and pull the fan shroud and clean the coil and re-gap clean mags in flywheel any rust will give you low spark. and one other thing you cant just unplug the yellow wire from the low oil unit unplug the lil silver box take it out of line to test. I have found that that box when it starts to go bad and it gets worm will ground the coil. DID you replace the carb gashets or reuse and look at the plastic carb insulator for a crack

I had already pulled the oil alert wire.

By gas tank clean screen, do you mean the fuel filter? I don't see any other screen. I replaced the fuel filter with a new one and a new fuel line. I think the fuel flow is good - if I disconnect the carb, the fuel flows out of the line quickly.

The new carb came with cardboard gaskets. I used those when I mounted the new carb.

Anyway the engine runs about the same with old carb, old gaskets and new carb , new gaskets, so unless both sets of gaskets are no good, it shouldn't be the gaskets.
The new carb also came with a plastic insulator, but I didn't replace that, or of course it's gasket. I don't see any cracks on the old one. It looks to me like it just pulls off. Is that right? I pulled pretty hard on it and it doesn't budge. I couldn't find any instructions on how to remove it and I was afraid that it might be fastened in someway that I can't see.

 

[AVB]

Here's a thought it may not even be the engine that is the prpblem but instead the hydraulics malfunctioning. Try separating the engine from the splitter and test.

 

[PDX Man]

Here's a thought it may not even be the engine that is the prpblem but instead the hydraulics malfunctioning. Try separating the engine from the splitter and test.

That seems like a long shot to me, given that the engine will run for a while at idle and then die when the throttle is opened up.

 

[backhoelover]

need to check and make sure that the black insulator is not crack or missing (between carb and cylinder head) will not run with out it has a cut out grove to vent the carb bowl

 

[backhoelover]

also need to check valve like fish said. if there off then valve timing is off.

 

[backhoelover]

also need to make sure cam is not wore out. i seen alot of log splitters with high hour and cam wore out. they would idle and wouldnt take any throttle

 

[PDX Man]

...
The new carb also came with a plastic insulator, but I didn't replace that, or of course it's gasket. I don't see any cracks on the old one. It looks to me like it just pulls off. Is that right? I pulled pretty hard on it and it doesn't budge. I couldn't find any instructions on how to remove it and I was afraid that it might be fastened in someway that I can't see.

I got the insulator off and the gasket was brittle and fell apart - not surprising. After I scrape the remains of the old gasket off, I'll put on the new gasket and new insulator and carb. I'm wondering about the cardboard gaskets that came with the new carb. Are they any good? Should I get a better set of gaskets? Anyone know a good source?

 

[backhoelover]

can you get a pic of the gaskets. all my honda gaskets are light gray or green

 

[PDX Man]

... I would ... pull the fan shroud and clean the coil and re-gap clean mags in flywheel any rust will give you low spark. ...

I pulled the fan shroud and there is definitely rust. Where, though would rust be a problem? Just on the magnet? Or on the whole flywheel outer rim? Here are pictures of what I have:

 

[PDX Man]

can you get a pic of the gaskets. all my honda gaskets are light gray or green

Here are the original gaskets on the left and what came with my new carb on the right. One of the original gaskets is actually a metal plate with a rubbery insert. It is hard to believe that if Honda thought that was needed, that a cardboard gasket will do the job.

 

[Fish]

Take off your valve cover, and the spark plug out. Find TDC and snap a pic.

I am guessing that one of your valves has little or no clearance.

Did you check for fuel flow yet?

 

[PDX Man]

Take off your valve cover, and the spark plug out. Find TDC and snap a pic.

I am guessing that one of your valves has little or no clearance.

Did you check for fuel flow yet?

I checked fuel flow by removing the fuel line from the carb. Fuel flows quickly and steadily. I haven't tested by opening the carb bowl, but it seems unlikeley that both old and new carbs would have a fuel flow problem. If I should test that, I can do it as soon as I put a carb back on - it is off while I'm looking at the ignition coil and flywheel.

I'll need to search a bit on how to remove the valve cover and then I'll report back with a pic.

 

[Wonkydonkey]

My tuppence worth,

Do you leave the fuel tap on while not in use, ? What I'm about to say, can happen quicker if the tap is left on while not inuse, but can also happen but slower if the fuel tap is switched off after use.
The old carb, have you taken the bowl off, ?? If you have/haven't what does the inside look like? The reason is because when fuel sits around and evapourates, it leaves a varnish like substance. This. Can be cleaned off with a green scrubby thing. This varnish does flake off and can block the main jet, or in your case partly block it, and by using the choke. You richen the mixture and it will start but opening the throttle the air flow increases but the fuel does not.

So get a flat head screw driver and take out the jet and make sure it's clean you can use a thin bit of wire to poke out any crud or a blast of air but the wire is what I've used before.
As for you new carb, I don't think it's set up properly

I hope this helps
If you'd need help in locating the main jet. ask, but you should be able to see it in the manual

Ps I've fixed a few engines with this problem of a blocked jet

 

[Wonkydonkey]

So I looked thouht the manual
Here's the page,
Undo 9 the set bolt

As you can see it says clean with compresed air (main jet no11 and also 12