Boiling Gas on 122

[Nailhead]

I've had a running problem with my 122 that I think I finally found the cause of yesterday: while mowing a yard that gets pretty grown over (the owner only wants it mowed every two weeks and it is irrigated), my 122 will gradually lose power and die. If I let it sit for a few minutes, it will start up, and usually repeat the problem until I add gas to the tank (I don't keep it full so the gas doesn't sit too long & go off).

Yesterday, I didn't have a gas can, and for some reason, after it quit once, it decided to run without a problem until I got that yard mowed. When I got done, I noticed the gas was boiling in the inline filter (non-stock fuel plumbing) and in the tank. Like pasta boiling-- vigorous. This I think is the reason for the running problems.

How do I keep the fuel cool given it is sitting right above the engine?

I realize today's gas isn't that great, but we're stuck with it which tells me that fuel tank couldn't be in a worse location, and I might be stuck with mowing in fits & starts.

Any ideas appreciated.

[J-Mech]

The engine is overheating. Take the engine out, remove the engine tins and clean it. Then, tune the carb. It's likely a combination of running lean and being dirty. Gas shouldn't boil in the tank. Motor is too hot.

I'd also remove the online filter, run a new hose and install a sediment bowl, if it doesn't have one. If it has a sediment bowl with a screen, you don't need the filter anyway.

[jimbob200521]

For some reason, I am doubting that the gas was boiling. I'm betting you have a plastic gas filter and something tells me if the gas was boiling, the plastic may have a hard time dealing with that. Combine that with the fact that these machines were designed to run as they are, the gas tank is not so close to the engine that it would cause any adverse effects to the gas.

What I'm wondering is if you were seeing air bubbles and mistook it for boiling gas Check your gas lines to make sure they don't have any holes in them and maybe replace your filter, if they crack they can leak air and cause running issues.

Edit: I missed the part about it boiling in the tank, as well. However, something still seems off about this

[J-Mech]

Ryan, gas will boil. It does so at a much lower temp than water. Pretty unsafe really....Lots of vapors.

[jimbob200521]

Originally Posted by J-Mech

Ryan, gas will boil. It does so at a much lower temp than water. Pretty unsafe really....Lots of vapors.

Oh I know it'll boil, I wanna say somewhere around 190° (depending on additives) or so if memory serves. I had, however, missed the part in my original read about it doing it in the tank as well so in my mind, I was picturing bubbles in the air filter. I know some of the cheap filters people use (I'm guilty of it once or twice, as well) can crack if they have too much pressure on them or get an awkward bend or something. I was just going for the simple check first

[cubby102]

I had a k241 in a 102 that no matter what I did (at the time) it wouldn't stop doing it after running it for a hour or more mowing. I had taken all the shields off and cleaned out whatever was in there. Ended up loosing the pan gasket and front seal so I decided to freshen it up. I took a wire wheel to all the rust on the fins of the jug and when input it all bsck together I never had another issue with it. My guess is the rust scale was just enough to hold the heat in...

[zippy1]

What type of fuel filter you using?

[Nailhead]

Originally Posted by J-Mech

The engine is overheating. Take the engine out, remove the engine tins and clean it. Then, tune the carb. It's likely a combination of running lean and being dirty. Gas shouldn't boil in the tank. Motor is too hot.

I'd also remove the online filter, run a new hose and install a sediment bowl, if it doesn't have one. If it has a sediment bowl with a screen, you don't need the filter anyway.

I was in the local CC dealer to buy a gasket or something for the sediment bowl when the older gent behind the counter suggested the fuel components that I'm running: new rubber hose, an inline 90-degree shutoff valve, an inline fuel filter (conical in shape), spring clamps, and various barbs for adapting to the tank & carb. Lyle said this was an improvement over the stock hard line/glass bowl setup, that that's what he runs on his old CC's. I've heard from several people he knows his stuff so I took his word for it, but I'll reinstall the old parts if that'll help.

As for engine removal, at this very moment I can think of few things I want to do less. Maybe that'll change, probably will, but I have zero interest in it right now. I've had old Fiats that gave me less trouble than this thing.

Thank you very much for the help.

[Nailhead]

Originally Posted by jimbob200521

For some reason, I am doubting that the gas was boiling. I'm betting you have a plastic gas filter and something tells me if the gas was boiling, the plastic may have a hard time dealing with that. Combine that with the fact that these machines were designed to run as they are, the gas tank is not so close to the engine that it would cause any adverse effects to the gas.

What I'm wondering is if you were seeing air bubbles and mistook it for boiling gas Check your gas lines to make sure they don't have any holes in them and maybe replace your filter, if they crack they can leak air and cause running issues.

Edit: I missed the part about it boiling in the tank, as well. However, something still seems off about this

That gas was at a rolling boil, like when you cook ramen. If I was able to post a video here, I would have shot one for informational purposes.

As for air bubbles, being a gravity-fed fuel system any leak in it would just allow gas to drip out. It's fuel-tight, no leaks anywhere.

Thank you for the suggestions.

[Nailhead]

Originally Posted by zippy1

What type of fuel filter you using?

A little cone-shaped one with a metallic-looking element in it, like sintered metal or something. CC enthusiast recommended.

It works great until the gas heats up.