Tecumseh OHH60 Problems After New Carb
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Hellion
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Without posting carb pics (seems a ridiculous request, right?) and explaining other symptoms in no-nonsense detail, this is a maddening ordeal. Still haven't seen your actual carburetor so for all we know, you could be running it with the choke closed. I'll take a shot in the dark:
Symptoms of Lean and Rich
Here are some basic symptoms, some duplicate:
Lean
Reduced Power - Sluggish at certain RPM's. Wide open throttle yields no power. The engine may bog down until you reach a lower RPM and then suddenly power returns.
Difficulty Starting
Spark plugs are clean - No residue. Insulator may be white.
Runs better at higher altitudes - Air/fuel ratio becomes normalized due to reduced atmospheric pressure allowing fuel into the venturi easier.
Backfires - Popping on deceleration for a lean idle circuit or backfires in general.
Runs on choke - The vehicle may run on choke when it's warm but stalls if the choke is turned off.
Idles poorly - Fluctuations in idle RPM, stalling
Engine runs hot - Due to more oxygen than fuel, combustion temperatures are hotter reflecting on a temp gauge.
Hanging idle - The engine idles high and then drops and stalls. Typically a lean condition caused by an air leak between the butterfly and the head or a vacuum line that is not attached.
Sharp Odor - The exhaust smell may be sharp and burn your nose. This is NOx or Nitrogen Oxide. It's created by high temperatures in the combustion process between nitrogen and oxygen. Although NOx is present in all exhaust it can be more pronounced in higher combustion temperatures associated with lean conditions with more oxygen. More oxygen=higher burn temp
Rich
Reduced Power - It has less power but seems to be OK and runs.
Reduced Fuel Mileage - You're using more fuel per cycle so your mileage becomes worse.
Rough Idle - Combustion takes a just a bit longer with more fuel and at lower RPM's the engine can idle rough. Unlike a miss-fire on a spark plug, this idle seems fine if the idle is turned up just a bit.
Spark Plug Black - Carbon buildup on insulator and electrodes of plug. Wipes off your finger as sooty and black. Carbon is a conductor of electricity and getting considerable carbon buildup from a rich condition will ground the inner electrode down the positive insulator. When this condition occurs there will be no spark. You can clean the spark plug with carburetor cleaner and re-use.
Exhaust Exit is Black and Sooty - Excessive carbon buildup in the exhaust is thick and overly grimy. A properly jetted carburetor will leave a nice grey scale color in the end of the exhaust pipe.
Odor of unburned fuel - In cases of a very, very rich mixture you may smell some unburned fuel coming out of your exhaust. This could be due to a grounded out spark plug from too much carbon buildup preventing the combustion process in a cylinder or so much fuel that complete combustion is not occurring.
Runs better with more air - If you remove your air filter and the engine begins to run a bit better with more oxygen in the mix it is likely you have a rich condition.
Runs worse at altitude - If the engine starts to run worse at higher altitude with reduced oxygen, it's likely a rich condition.
Black Smoke - If you have black exhaust when you rev it, it's rich. You can get a light colored rag and place it over the exhaust lightly and rev it to see if you get carbon/black residue on the rag.
Symptoms of Lean and Rich
Here are some basic symptoms, some duplicate:
Lean
Reduced Power - Sluggish at certain RPM's. Wide open throttle yields no power. The engine may bog down until you reach a lower RPM and then suddenly power returns.
Difficulty Starting
Spark plugs are clean - No residue. Insulator may be white.
Runs better at higher altitudes - Air/fuel ratio becomes normalized due to reduced atmospheric pressure allowing fuel into the venturi easier.
Backfires - Popping on deceleration for a lean idle circuit or backfires in general.
Runs on choke - The vehicle may run on choke when it's warm but stalls if the choke is turned off.
Idles poorly - Fluctuations in idle RPM, stalling
Engine runs hot - Due to more oxygen than fuel, combustion temperatures are hotter reflecting on a temp gauge.
Hanging idle - The engine idles high and then drops and stalls. Typically a lean condition caused by an air leak between the butterfly and the head or a vacuum line that is not attached.
Sharp Odor - The exhaust smell may be sharp and burn your nose. This is NOx or Nitrogen Oxide. It's created by high temperatures in the combustion process between nitrogen and oxygen. Although NOx is present in all exhaust it can be more pronounced in higher combustion temperatures associated with lean conditions with more oxygen. More oxygen=higher burn temp
Rich
Reduced Power - It has less power but seems to be OK and runs.
Reduced Fuel Mileage - You're using more fuel per cycle so your mileage becomes worse.
Rough Idle - Combustion takes a just a bit longer with more fuel and at lower RPM's the engine can idle rough. Unlike a miss-fire on a spark plug, this idle seems fine if the idle is turned up just a bit.
Spark Plug Black - Carbon buildup on insulator and electrodes of plug. Wipes off your finger as sooty and black. Carbon is a conductor of electricity and getting considerable carbon buildup from a rich condition will ground the inner electrode down the positive insulator. When this condition occurs there will be no spark. You can clean the spark plug with carburetor cleaner and re-use.
Exhaust Exit is Black and Sooty - Excessive carbon buildup in the exhaust is thick and overly grimy. A properly jetted carburetor will leave a nice grey scale color in the end of the exhaust pipe.
Odor of unburned fuel - In cases of a very, very rich mixture you may smell some unburned fuel coming out of your exhaust. This could be due to a grounded out spark plug from too much carbon buildup preventing the combustion process in a cylinder or so much fuel that complete combustion is not occurring.
Runs better with more air - If you remove your air filter and the engine begins to run a bit better with more oxygen in the mix it is likely you have a rich condition.
Runs worse at altitude - If the engine starts to run worse at higher altitude with reduced oxygen, it's likely a rich condition.
Black Smoke - If you have black exhaust when you rev it, it's rich. You can get a light colored rag and place it over the exhaust lightly and rev it to see if you get carbon/black residue on the rag.
chancer
ɔ ɥ ɐ u ɔ ǝ ɹ
Yeah, I bet its that.
It is a new carb
Sorry for that. Crap..... Flywheel and coil is clean too im thinking. Tecumseh. Never liked them myself. I got lucky with mine. But then again I haven't even started yet this year.
---------- Post added at 01:20 AM ---------- Previous post was at 01:18 AM ----------
Get rid of the governor!!!!!
---------- Post added at 01:20 AM ---------- Previous post was at 01:18 AM ----------
Get rid of the governor!!!!!
Denny
Canned Monster
Pull the float bowl and make sure the jets are clear and there is no crap in there. With the goat urine they sell now called gasoline I have seen the inside of the fuel line start to break down before the outside does. Once you disturb the line all kinds of crud breaks free. Good Luck.
Denny
Denny
Poboy kartman
Senior Moments Member
He is in Maine, Send Mindy over there.
With a selfie stick?
james200017
Engine Chump
I'll post pics later today. I'll try to get lots of them.
---------- Post added at 06:10 AM ---------- Previous post was at 05:59 AM ----------
---------- Post added at 06:10 AM ---------- Previous post was at 05:59 AM ----------
And who is this Mindy you speak of?He is in Maine, Send Mindy over there.
Hellion
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Forum member.
james200017
Engine Chump
james200017
Engine Chump
Anything guys?
Poboy kartman
Senior Moments Member
I don't do 3rd party hosting sites with huge pictures. If you post thumbnails here, you'll probably get more help.
bob58o
SuckSqueezeBangBlow
I hope you didn't press the RED button!
https://www.youtube.com/watch?v=3YmMNpbFjp0
https://www.youtube.com/watch?v=3YmMNpbFjp0
james200017
Engine Chump
I can get it to idle, although it idles odd. The big problem is that I can give it no gas whatsoever, it just surges. Here are some pics on Imgur:
pics look fine as far as connections go. I say back out the screw that was under the black cap 1/8 of a turn at a time and see if you can get it to idle better and give it gas.
I know mine was finicky. One of them ended up being lost and I replaced it with a regular old 10-32 thread screw and it runs perfectly.
My other engine I added a spring to the screw that came with the carb because it kept unscrewing itself out just with engine vibrations, probably how I lost the other one.
I know mine was finicky. One of them ended up being lost and I replaced it with a regular old 10-32 thread screw and it runs perfectly.
My other engine I added a spring to the screw that came with the carb because it kept unscrewing itself out just with engine vibrations, probably how I lost the other one.
Hellion
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Surging can also be due to a governor setting
james200017
Engine Chump
Just to inform all that helped (thank you) that I took the easy way out and bought a Predator 212cc. After getting fed up with the Tecumseh and its support or lack thereof, we got it taken to a small engines mechanic we know. He said the carb was junk, and that when they formed the metal, the part where gas comes into the carb had been covered. He fixed it. That little repair was $50. Thinking to myself that $50 more could have gotten me a new engine, but oh well. I get home, unload it, start it up as normal. I ease on the gas, gets up to top speed, then surges. I was done. Today, I bought a Predator 212, installed it in 15 minutes (boy was that easy) and let it break in for 3 hours at 1/3 throttle. After some trouble with the throttle linkage (not loosening the 10mm throttle bolt) it works perfectly. Haven't been able to test it out yet as it's too dark. The Tecumseh had an alternator of some sorts that would give power to some lights up on top of the kart. I'll have to find a way to add the alternator to the predator, but in due time. Just wanted to update and say thanks to all that helped with this annoying (and costly) endeavor.
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