Scrounging Firewood (and other stuff)

[JimR]

So a question for those familiar with engines on riders. ( I'm a 2 stroke only guy) I've been roped into working on a rider and it's giving me fits. My question is, knowing the case got flooded with gas due to a bad carb seal, could there be valve and or push rod damage and could it cause a " runs only on choke situation?"

Anytime I have this problem it is a collapsed fuel line from the tank, a bad fuel pump or suction line from the pump to the motor or a plugged up main jet passageway. I have done plenty of fixes on mowers and snowblowers with that same problem.

 

[diver64]

Check your fuel and air lines. Make sure where they attach from the tank to the carb are not loose or the line damaged. The line itself may be old and need to be replaced. I just went through the exact thing you did and ended up replacing all the lines. I also found a little chunk of bug in the fuel line at the same time as well as the line rotting out under a clamp. All fuel and air lines.

You might want to check the fuel tank if you haven't already. My had a bunch of earwigs in it. How they got there I don't know but I removed the tank and cleaned it out at the same time.

 

[sean donato]

Don’t know if it’s an option but I’ve seen some shops with lights part way down on the walls, really helped with more light at floor level.

Yes, it could be. Basically don't have any power ran to anything other then the air compressor and main shop lights. Could run some zip cord and hang a few lights to see how it works.

 

[diver64]

Don’t know if it’s an option but I’ve seen some shops with lights part way down on the walls, really helped with more light at floor level.

I've also seen lights mounted vertically down the walls every few or several feet.

 

[bob kern]

It's possible there's a fuel supply issue too. Screen in the tank clogged up slowing fuel flow. Would be helpful to know what it's on/ what engine it is. Possibly point you in a better direction. There are some passages you won't be able to rod out depending on the carb configuration. Makes it difficult to diagnose. Does it surge while running without the choke, or on partial choke or just not run at all without the choke?

11 or 12 hp Briggs single cylinder.
Good flow to the carb.
Smooth with choke on but dies quickly if I try to back in out of the choke position.
Only other thing I could possibly imagine is the float not pulling the needle up high enough.

 

[bob kern]

Check your fuel and air lines. Make sure where they attach from the tank to the carb are not loose or the line damaged. The line itself may be old and need to be replaced. I just went through the exact thing you did and ended up replacing all the lines. I also found a little chunk of bug in the fuel line at the same time as well as the line rotting out under a clamp. All fuel and air lines.

Hmmm I could try the fuel line. Not much for an air line except a breather tube.

 

[bob kern]

You might want to check the fuel tank if you haven't already. My had a bunch of earwigs in it. How they got there I don't know but I removed the tank and cleaned it out at the same time.

Thanks. Good flow to the carb.

 

[MechanicMatt]

11 or 12 hp Briggs single cylinder.
Good flow to the carb.
Smooth with choke on but dies quickly if I try to back in out of the choke position.
Only other thing I could possibly imagine is the float not pulling the needle up high enough.

How full is the bowl when you lower it?

The float may not be adjusted correctly allowing adequate fuel

For giggles, did you do a compression test?
Air/Fuel/Spark

Compression falls under Air in my mind…

 

[bob kern]

How full is the bowl when you lower it?

The float may not be adjusted correctly allowing adequate fuel

For giggles, did you do a compression test?
Air/Fuel/Spark

Compression falls under Air in my mind…

I have not done a compression check. Do you believe that could cause running on choke only?

 

[bob kern]

It does seem to have plenty of resistance on the starter. I put back in the old needle and float which it had been running fine with and no change.

 

[Lee192233]

It does seem to have plenty of resistance on the starter. I put back in the old needle and float which it had been running fine with and no change.

There almost has to be something blocked in the carb. There often are passages that can't be cleaned without taking plugs out. My two cents, hard to diagnose like this.

 

[Lionsfan]

There almost has to be something blocked in the carb. There often are passages that can't be cleaned without taking plugs out. My two cents, hard to diagnose like this.

I agree. Are there any welch plugs in the fuel chamber you can pick out?

 

[bob kern]

I agree. Are there any welch plugs in the fuel chamber you can pick out?

There was one Welch plug . I removed it and there was no crud under it. Out of curiosity, I ordered a new one. I hear it's a crap shoot on those replacements, but for $20 , I'll give it a shot.

 

[Lee192233]

@bob kern I just had a thought. Have you checked the muffler to ensure it flows? Maybe a mud dauber decided to build a nest in it.

 

[diver64]

Thanks. Good flow to the carb.

If you have good flow then it's either air or the carb imho. Carbs are cheap but first replace the lines then look at either rebuilding the carb or buying a new one. That would be my course of action. Interested in what you find out

 

[diver64]

The rider I referenced is a Briggs. I'm going out on a limb and considering what you are saying that you have a carb problem or a carb gasket.

 

[chipper1]

11 or 12 hp Briggs single cylinder.
Good flow to the carb.
Smooth with choke on but dies quickly if I try to back in out of the choke position.
Only other thing I could possibly imagine is the float not pulling the needle up high enough.

You sure the choke cable is on properly, some can be put on backward and you'd basically be choking it when you shut and opening the air when it's not choked.
You seen the one I was dealing with this weekend, I've seen some odd stuff.
One I've only seen once was an engine that ran perfectly most the time, then it would spit and sputter, but with no consistency.
Ended up having about a teaspoon worth of water in tue fuel tank that would cover the outlet, although everytime I checked the fuel filter it was full. I just happened to catch it perfectly over the outlet one time.
Hope you figure it out soon.

Post a picture of the carb so I can see the bowl, maybe I'll remember another odd experience.

 

[bob kern]

@bob kern I just had a thought. Have you checked the muffler to ensure it flows? Maybe a mud dauber decided to build a nest in it.

Thanks!
Yet another good thought but it flows well. It blows right on my knee when I'm mess ing with the carb!

 

[chipper1]

Thanks!
Yet another good thought but it flows well. It blows right on my knee when I'm mess ing with the carb!

I thought of another odd one. A friend of ours had a push mower I had cleaned the carb on, fast forward a few yrs and someone else cleaned it again in the spring(I was busy). She calls me and says it will only run on either, so I head over. Pull the carb and it was really clean, then I remembered that dang thing, it had done the same thing to me that the new guy was having a problem with. Ends up the fuel flows into the bowl thru a hole in the bowl screw/bolt, if the bolt isn't clocked properly, you get no fuel into the bowl.
But, that was a smaller engine, and I don't think it even had an emulsion tube, odd one though lol.

 

[bob kern]

This is the demon carb in question!