HH100 Losing Power When Hot

[ChiefRider 0]

My Charger 9 runs like a new machine for the first 40 or so minutes that I use it. Without warning, the engine will cut out unless I either quickly choke it, or disengage the hydro trans and/or drive to the mower, thereby relieving it of its load. It will continue to operate at this point at about half choke, and I can re-engage the trans to get back to the garage. The fuel tank is clean, I have new fuel line and an inline filter. The engine is equipped with a fairly new Tecumseh carb that I have just cleaned. My cleaning amounted to removing the carb, removing the bowl and float, remove the idle needle valve. I used compressed air to blow thru any internal passages, wiped needle valves clean with lint free cloth and reassemble with new bowl gaskets. I did not remove the main jet, although I think this is only critical on the Walbro carb. Any thoughts? I'd like to be able to use the tractor for more than 3/4 of an hour at a time!

Thanks!

[tunahead72 2,334]

A bunch of questions for you, just to get the discussion started:

• [*:25yzs7yg]How was it running before you cleaned the carb? Has it always run like this?[*:25yzs7yg]Did you soak the carb in anything when you cleaned it, or use a spray carb cleaner?[*:25yzs7yg]Can you see anything nasty in the fuel filter?

[ChiefRider 0]

I last used the tractor about a year ago, and it ran fine- no problems. I was surprised, as my dad (previous owner) told me that it would only run choked. This year, it would only run choked, so I pulled the carb. It was surprisingly clean inside, a little fine sediment in the bowl, no sign of varnish. I didn't use any cleaner just air. I'm puzzled because this happens consistantly after 40+- minutes. I'm assuming this may be a threshold as to when the engine is heat-soaked, instigating a change.

I can't ask my dad, as he is no longer with us, but I think he replaced the head, and I see in his notes he had valve clearance specs written down. The engine runs great, no smoking at all, but I think the valves sound a little noisy, maikng me think too much clearance. I'm wonderng if heat expansion of the block could increase clearance and cause this? I'm just hoping to zero in on this quickly so I can get back to work!

Oh and the fuel filter is clean and clear.

[tunahead72 2,334]

I'm not familiar with the Tecumseh carbs on these machines, so I'll have to let some of the more qualified experts on this forum weigh in on this problem.

My initial thought is that your carb might be set too lean, which would explain why it runs better with the choke partially closed. It doesn't explain why it ran better for you last year, unless your carb isn't as clean as it appears. How fresh is the gas that's currently in it? Does the engine appear to be overheating at all? That could indicate a too lean mixture also.

Personally, I would make sure it has fresh fuel, and then try adjusting the carb if that's possible (engine warmed up, both main fuel & idle air mixture screws, if it has both). If that doesn't help, I would probably pull the carb and give it a thorough soaking and cleaning -- I would wait to hear from others here for more specific advice on these carbs.

Somebody with more expertise should be along shortly.... :hide:

[algrc120man 0]

:WRS: is the carburetor fixed or adjustable jet if you have a fixed jet carb there are holes in the bowl nut that have a small clog causing a lean run if it is an adj jet try one and a half turns out and se if it clears the problem if not you will need to soak or use spray cleaner in every possible spot in the carb these tec carbs are very very very sensitive to even the finest dirt if all checks out in the fuel system start checking ign componets. also loose valves wont effect warm running conditions in this case it will be the tight valves that will swell and create to much valve lift resulting in loss of power and compression but i thnk mostly you have a fuel problem. hope this helps :disgust:

[Kelly 1,028]

Have you checked the carb to block gasket? you did install a new one when you had the carb off right??

[ChiefRider 0]

Thanks guys, some good points. Gas is clean and fresh, idle jet out 1.5 turns, hi-speed at about 2, and I don't believe it is running too hot. Currently, it only needs choke after 40 minutes- Prior to that it runs great with no choke at all. I will be pulling the carb again and soaking it, being especially thorough in cleaning. And no, I didn't replace the carb to block gasket- I will now, though!

[puddlejumper 67]

I have never had a bigger techy but if it was a kohler my money would be on a bad fuel pump.

[rmaynard 14,865]

Hmm...have you checked for a blocked gas cap vent hole? Try running it until it dies, then loosen the gas cap and see if it returns to normal.

[puddlejumper 67]

BOB, you could definitely be on to something. That one has bit me several times. And that answer always seems to come to mind after I have completely confused myself and take time to kick back and calm my nerves.

[ChiefRider 0]

I made sure the cap was fine when I replaced the fuel line, but I haven't checked at the point it starts to act up- I'll add that to the list for tomorrow.