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Author Topic: Carb cutting out.  (Read 16979 times)

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Offline berthyd

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Re: Carb cutting out.
« Reply #15 on: June 29, 2011, 08:16:42 pm »
Quote from: foolnhismoney on June 29, 2011, 08:40:46 am
Anybody got a picture of one they externally vented?

I have plenty of pix, but you can't see them :badgrin:

Put a fuel pump on it. If this is a "built" motor, gravity will NOT keep it fed.

And yes, all the needle and seats are the same in the OHV Tec engines.

Bert
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Offline trbinrat

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Re: Carb cutting out.
« Reply #16 on: June 29, 2011, 11:36:33 pm »
Well I took the carb apart and the o-rings were ok. Checked the main jet and it was clear and made sure that the float worked properly.

So it looks like it will get a external vent and after looking at it I figured it out.

 And after talking about it. It seems I was pushing the mower harder and harder into the corners at the end of the race trying to catch the front runner. This would correspond with the engine cutting out at the end of the race and not at the beginning when I started in the back and making my way through the pack.

Mark

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Offline trbinrat

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Re: Carb cutting out.
« Reply #17 on: July 10, 2011, 08:23:40 pm »
I installed a external vent.  put new o-rings in made sure that all the passages were clear. Checked the float and the gasket that the float needle seals on all ok.It was not idling very well and running lean. I opened up the low side jet .002 from stock and opened up the main jet to .046 to get it to run right. Took it to the track today and  it ran better but still lean. Still coughing in the corners.

Going to try a pump next.

Also did a leak down test that checked out ok and adjusted the valves to factory spec.

Anyone got any thoughts on this. seems that I shouldn't have to have the jet opened up that much.

Thanks
    Mark
 
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Offline trbinrat

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Re: Carb cutting out.
« Reply #18 on: July 16, 2011, 10:52:48 pm »
I put the fuel pump on and did some more tweaking on the carb. Took it to the track tonight and it ran like it should. no more falling on its face in the corner and more power out of the corner.
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Offline berthyd

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Re: Carb cutting out.
« Reply #19 on: July 17, 2011, 08:59:39 am »
Quote
Put a fuel pump on it. If this is a "built" motor, gravity will NOT keep it fed.

Bert
Ahem....when the old man talks, you may want to listen....

Bert
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Offline trbinrat

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Re: Carb cutting out.
« Reply #20 on: July 17, 2011, 07:45:13 pm »
Thanks Bert I never doubted you.  I did listen that's why it's on there. But if you don't go through the steps you will never find the route of the  problem. The lack of a pump wasn't the whole problem but was most of it.

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Offline justin case

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Re: Carb cutting out.
« Reply #21 on: July 20, 2011, 09:08:18 pm »
(Mod-Xr) :confused:

General Regulations .  Local Chapter

Stock.  •   The engine must be as delivered from the factory.
Governed engine- Single cylinder VIB or OHV    3650 RPM
17 HP and under.
NO modifications . :confused:
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Offline foolnhismoney

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Re: Carb cutting out.
« Reply #22 on: July 20, 2011, 09:12:37 pm »
the rules allow adjustable main jets on briggs whats wrong with changing jets in a tecumseh. Lots of motors run pumps. we have a bunch of them on modxr's
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Offline Burwell555

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Re: Carb cutting out.
« Reply #23 on: July 21, 2011, 12:50:33 am »
Some have pumps, some don't. How do you prove that 'my motor had a pump and his didn't'? Ya can't!
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Offline trbinrat

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Re: Carb cutting out.
« Reply #24 on: July 21, 2011, 11:06:22 am »
Quote from: justin case on July 20, 2011, 09:08:18 pm
(Mod-Xr) :confused:

General Regulations .  Local Chapter

Stock.  •   The engine must be as delivered from the factory.
Governed engine- Single cylinder VIB or OHV    3650 RPM
17 HP and under.
NO modifications . :confused:

Your allowed an air cleaner and pipe. So I can't rejet the carb and add a pump To prevent the motor from burning up.This motor was so lean at the start that it was running hot and wouldn't even color the plug one bit even after 50 laps.

Maybe Grubby will chime in on this
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Offline THawley08

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Re: Carb cutting out.
« Reply #25 on: July 21, 2011, 11:49:44 am »
Use stock jets there are quite a few and our tec came with a fuel pump.
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Offline George Herrin

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Re: Carb cutting out.
« Reply #26 on: July 21, 2011, 01:12:50 pm »
I have yet to see a single ohv not have a fuel pump and many are not on the motor butthe chassis which means it does not go with the motor when it's took off said junk mower and as many different jets and nozzles available with the carbs there is no way to tech them if you go by as delivered. Ain't gonna happen and I know what I am looking for to boot
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Offline GRUBDIGGER

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Re: Carb cutting out.
« Reply #27 on: July 21, 2011, 03:04:27 pm »
YOU ARE ALLOWED TO RUN AN ADJUTABLE JET. DOES NOT MATTER WHAT BRAND OF ENGINE.IF THERE IS NO ADJUSTABLE JET FOR YOUR CARB ,THE NEXT BEST THING TO DO IS DRILL IT OR INSTALL A LARGER EMULTION TUBE. THATS OK. ALL ENGINES WILL TAKE A FUEL PUMP. RULE # 1 IS YOU CAN USE AN AFTER MARKET AIR FILTER AND OPEN EXHAUST. AFTER YOU CHANGE THOSE 2 THINGS,IT WILL NEED MORE FUEL.
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Offline Honey Badger

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Re: Carb cutting out.
« Reply #28 on: April 05, 2012, 11:59:53 am »
So I know this is an old post and all, but I must ask about fuel pumps.  Is there a difference between the vacuum fuel pumps used on briggs singles/ twins compared to the tecumseh?  I see that the needle and seat are the same part numbers for the gravity and fuel pump set ups for the tecs.  So do tec's like a lower fuel pressure than a briggs?  I guess am I ok to use the briggs pump or am I going to load up my carb easier?  Thanks in advance. 
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Offline Burwell555

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Re: Carb cutting out.
« Reply #29 on: April 05, 2012, 12:38:37 pm »
I ran a Walbro pump last year. It was available new at the time in a pinch when my old pump went to crap. Which was a Mikuni that worked great until it for some reason got a hole in the diaphragm. I dont think youll notice any difference between the different pumps honestly.
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