Bad gas?

[buckeyefarmer]

I have same engine on my husq. Yesterday, it started shutting off like it was out of gas, but had fresh gas bought the night before.

 

[GirlWhoWantsTractor]

I have same engine on my husq. Yesterday, it started shutting off like it was out of gas, but had fresh gas bought the night before.

One quirk these tractors have, if you mow in hot weather, after around an hour or so it starts sputtering and then cuts out, exactly like it's out of gas--but it's not. I was TOLD (have no way of judging if this is right or not) that they are prone to some kind of vapor lock due to the fuel *something* (line? filter? some other thingummy?) being too close to a part of the engine that gets hot. Flip the hood, let it cool off for a while and it's good to go again.....

What mine is doing is a little different; backfiring.

 

[buckeyefarmer]

One quirk these tractors have, if you mow in hot weather, after around an hour or so it starts sputtering and then cuts out, exactly like it's out of gas--but it's not. I was TOLD (have no way of judging if this is right or not) that they are prone to some kind of vapor lock due to the fuel *something* (line? filter? some other thingummy?) being too close to a part of the engine that gets hot. Flip the hood, let it cool off for a while and it's good to go again.....

What mine is doing is a little different; backfiring.

Heat and cutout is what it was doing. I opened gas tank and there was pressure released. I picked up a new fuel filter.

I have had backfire on other 1 cyl mower engines, not this one.

 

[plowhog]

they are prone to some kind of vapor lock ...

I was flying that same Beech Baron 55 over the Sierra Mountains when the right engine quit. It was over 100F when I took off, and heat build up from a maximum performance climb to clear the ridges boiled the fuel in the feed line to the right engine. Fuel starvation from too hot fuel lines leading to vapor lock killed the engine, despite full fuel tanks.

If you insulate your fuel line on your mower it should never do that again. I couldn't do that to the Baron as it was a "modification" to the aircraft so I just had to baby it a bit on a hot day.

 

[AWSubie]

I am unfamiliar with this engine, but it sounds as if you have a vacuum leak. Check the engine closely to see if the service people may have left a small hose or rubber tube off of a fitting (most likely at or around the carb). Check any hose clamps and tighten if loose.

 

[GirlWhoWantsTractor]

I was flying that same Beech Baron 55 over the Sierra Mountains when the right engine quit. It was over 100F when I took off, and heat build up from a maximum performance climb to clear the ridges boiled the fuel in the feed line to the right engine. Fuel starvation from too hot fuel lines leading to vapor lock killed the engine, despite full fuel tanks.

If you insulate your fuel line on your mower it should never do that again. I couldn't do that to the Baron as it was a "modification" to the aircraft so I just had to baby it a bit on a hot day.

What would you use to insulate it?

(Glad you made it!)

 

[GirlWhoWantsTractor]

I am unfamiliar with this engine, but it sounds as if you have a vacuum leak. Check the engine closely to see if the service people may have left a small hose or rubber tube off of a fitting (most likely at or around the carb). Check any hose clamps and tighten if loose.

Thank you. Will check everything tomorrow.

 

[GirlWhoWantsTractor]

Could not find our Sea Foam, and the problem with living in the boonies is the one store within an hour+ drive is closed on the weekend. So no progress.

Will get the Sea Foam on Monday and check everything and try to figure it out.

Thanks to everyone for your input. We'll see what happens!

 

[Maxify55]

Your overhead valves need to be regapped.

Remove the valve cover and reset the gap to both the intake and exhaust lifters.

It has to be done every now and then with OHV engines.

Consult your owners manual for the clearences. (Lash/Gap)

They're usually between ,004 and .007.

Your feeler gauge will be your new friend.

 

[plowhog]

What would you use to insulate it?

There are many products. Try something like this:

Fuel Line Heat Wrap | Fuel Line Insulation | Heatshield Products

Thanks for the kind thoughts. Having an engine quit at 12,000 ft was not as exciting as the (other) plane that had a fire in the dash panel at 17,000 ft. Takes a while to get on the ground from that altitude ... plus it was a pressurized cabin.

I think Summit Racing store should have a good selection of heat shield products.

 

[Rocky J]

I had a HOYT-CLAGWELL , mine was re-badged as a JINMA from Rural King , Is it possible one cylinder is not firing and pushing un-burnt fuel into the exhaust being lit from the good cylinder , only detectable as a backfire sound at a idle . No more then you get to use it you would not have a feel for the lack of power.

 

[Rocky J]

As much electrical problems as you have had I would remove the shroud from the flywheel and un plug both kill wires from the coils , replace the shroud and test . They used a diode in each coil kill wire before they joined them together then into the harness, when good this only let the electricity go one way, if one of them opens it will not shut that cylinder off with the key , if it shuts and lets electricity go both ways this would allow that cylinder to see the other cylinder firing ,

 

[GirlWhoWantsTractor]

Okay, so turns out both Husq tractors were doing it, both had a recent service, and someone else put gas from winter into both of them......so seems likely bad gas.

Put some Seafoam in both tanks overnight. Today, both tractors still running rough, surging, although much less backfiring.

Next step, check if the plugs are fouled? Anything else? Should we try to drain the gas? More Seafoam?



(Rocky, I'm afraid I have no idea what you're talking about; no mechanic here. )

 

[GirlWhoWantsTractor]

There are many products. Try something like this:

Fuel Line Heat Wrap | Fuel Line Insulation | Heatshield Products

Thanks for the kind thoughts. Having an engine quit at 12,000 ft was not as exciting as the (other) plane that had a fire in the dash panel at 17,000 ft. Takes a while to get on the ground from that altitude ... plus it was a pressurized cabin.

I think Summit Racing store should have a good selection of heat shield products.

Sorry, which size? and with velcro closure or not? Do you use this on your tractor too?

 

[aczlan]

Okay, so turns out both Husq tractors were doing it, both had a recent service, and someone else put gas from winter into both of them......so seems likely bad gas.
Put some Seafoam in both tanks overnight. Today, both tractors still running rough, surging, although much less backfiring.
Next step, check if the plugs are fouled? Anything else? Should we try to drain the gas? More Seafoam?
(Rocky, I'm afraid I have no idea what you're talking about; no mechanic here. )

Fill them up with fresh high test (to dilute the old gas) and run them hard. If you have one, you could siphon the old gas out first, but its up to you.

Aaron Z

 

[GirlWhoWantsTractor]

UPDATE:

Okay, fresh gas and Seafoam a week ago took care of the backfiring, but both tractors continue to surge, with loss of power overall. One has now developed a strong smell of gas when running. Changed out the spark plugs today. Tips WERE coated with carbon, but the new plugs made little to no difference.

Sounds like back to the dealer. Imma seriously kill Jay.

 

[GirlWhoWantsTractor]

FINAL UPDATE:

Both tractors were still running like cr@p despite new fuel filters and spark plugs. Dealer said if you just drain out all the gas and replace the fuel filter, that fixes it 90% of the time. So, disconnected the fuel lines and drained all the gas out of both tractors (messy job, resulting in 9 gallons of good/bad gas mixture--to be used on a bonfire). Replaced the fuel filters again (both showed a lot of varnish and gunk). This seemed to fix it on the newer Husqvee. But the older one was still backfiring and surging, so it was obviously the 10% that needed more work. New carb was $250 and the old thing is probably only worth about that. So took off the carb and the dealer put it in an ultrasonic cleaner. Cost $50. He said the carb was "uncommonly dirty." Replaced the carb and it is running like new again. Probably had years of buildup from bad gas (it came with the house).

Fuel filters only around $2.50 each so bought a bag of them to keep on hand.

So, success at last, and I learned how to do some new things. Thanks everyone for the help.

 

[joecoin]

FINAL UPDATE:

...drained all the gas out of both tractors (messy job, resulting in 9 gallons of good/bad gas mixture--to be used on a bonfire).

So, success at last, and I learned how to do some new things. Thanks everyone for the help.

Nice to know you got them both fixed.

Don't burn that gas, filter it and put it in your car or truck.

 

[ChiefBodie]

So took off the carb and the dealer put it in an ultrasonic cleaner. Cost $50. He said the carb was "uncommonly dirty." Replaced the carb and it is running like new again. Probably had years of buildup from bad gas (it came with the house).

Never heard of an ultrasonic carb cleaner, but compared to taking one apart that sounds very desirable.

 

[GirlWhoWantsTractor]

Never heard of an ultrasonic carb cleaner, but compared to taking one apart that sounds very desirable.

Yes! My brother (shade tree mechanic) had never heard of it either. He was gonna help me "rebuild" the carb. This was cheaper AND easier. I did learn how to remove/reinstall a carb, so win-win.