Tec. h70 idles way high then dies?????>??

wolfgang123 · 08-10-2008, 06:02 PM

ok so i finally got my h70 running almost good you see i have a 12hp carb on my 7 hp Tec i check on this site before buying it and you guys said i would work, so i got it...it is an older carb but this is the first time it has been run since its rebuild.. and let me say they guy that did the rebuild did an amazing job. so i got it running no air filter but when i go to turn the idle down she kind of sputters and dies and when i try to give her throttle to keep her going she still just dies out. any ideas or adjustments on the carb i should do,,,also this was without an air filter would haveing one on make a difference

Mikes Bikes · 08-10-2008, 10:18 PM

Is it running good @ high speed?

Air filter will make a slight difference.

Sounds like your idle mixture is off.

I quick way to tell if it wants more fuel is to play with the choke: If it runs good with part choke, then you know it needs more fuel, adjust the idle mixture accordingly.

If it has no choke, start by turning the idle mixture screw all the way in. Turn out 1 1/4 turns. This should get it running. Adjust the idle speed screw to the desired speed. Now turn the mixture screw in by 1/8th increments, letting the engine settle down between each turn. The engins should speed up as you do this. When it starts to run rough, back the screw out till it runs good again, usually no more than 1/4 turn.

Now reset the idle speed.

Good luck.

**jimh** · 08-10-2008, 10:51 PM

If that doesn't do it, the check valve in the idle circuit is stuck. No way to fix that, other than a new carb. If the idle circuit is bad, the best idle you're gonna get is a up and down idle. It will surge a little, then nearly die, then surge and nearly die. The only way I'd ever buy a used tecumseh carb is off an engine that was running great, and they decided to use a slide carb or something. If they've set up a long time, even a rebuild won't fix them, due to having the check valve, which is prone to sticking.

Mikes Bikes · 08-11-2008, 09:23 AM

Quote:

Originally Posted by jimh

If that doesn't do it, the check valve in the idle circuit is stuck. No way to fix that, other than a new carb. If the idle circuit is bad, the best idle you're gonna get is a up and down idle. It will surge a little, then nearly die, then surge and nearly die. The only way I'd ever buy a used tecumseh carb is off an engine that was running great, and they decided to use a slide carb or something. If they've set up a long time, even a rebuild won't fix them, due to having the check valve, which is prone to sticking.

A quick check for this is to remove the carb, remove the bowl and float assy. Now hold the carb up to your ear and slowly rotate it upside down. You'll hear the check ball fall as yo do this. It helps to have a known good one to train your ear on. If you don't hear it, the carb will never idle well.

A proper rebuild of a Tec carb includes COMPLETE disassembly. That means removing the welch plugs. Soak it overnight in real carb solvent & then reassemble. Most folks won't do this, as it's easyer just to get a new carb. Ask your rebuilder if he did this. If not, there's a good chance the idle circuit is plugged up.

wolfgang123 · 08-11-2008, 07:32 PM

ok then i will check all that but when i started it up it had a jumping idle and before everytime i accerlarate it would bog and die off