How to make Tecumseh engine burn better?

[Fordiesel69]

I recently transplanted a Harbor Freight Predator engine onto an old vintage ariens snow tho. While most people talk about how smooth and awsome the power is, i am more impresed that my coat, scarf, and hat do not smell like choked exhaust. There is far less smell and emissions coming from the new engine. FAR LESS!!!!!!!!

I notice if you ever zip a throttle on a tecumseh, you will get large dropplets of fuel splashing back out the carb throat before the engine increased speed. On other engines like honda, kawasaki, and basically japanese based engines the carb appears to meter the fuel leaps and bounds better than lets say a tecumseh / briggs. There is not one single drop.

So is the carb the main reason why they burn so horrible? Can I have a fab shop make me up an adapter and simply put a more modern carb on my fleet or tecumseh engines to clean them up?

 

[K.Aoi]

Those Tecumseh engines were designed 50+ years ago and barely changed between then and when they stopped being made. The predators are one of the many honda-clones. They're also OHV and run leaner than older engines. There's not really anything you can do other than try replacing the carb but it's doubtful that will help. Being OHV will also help with the emissions aspect since the burn is more complete which means less unburned hydrocarbons and soot in the exhaust. Basically if you want cleaner running engines, replace the engines with modern ones.

 

[jeepman3071]

The modern engines do burn a lot cleaner, most of them run much leaner as well. The combination of leaner burn and OHV versus an old worn out flathead makes a big difference.

 

[K.Aoi]

For reference, I have a vertical shaft Tecumseh 3.8HP on a fb marketplace craftsman single stage. First flathead engine I've run in a while and yeah it definitely is more smelly than the OHV stuff I've used in recent years and also guzzles gas. I have a Craftsman FB marketplace lawnmower with the more powerful Briggs OHV engine and that thing burns nice and clean.

 

[jeepman3071]

The Chinese clones run pretty lean from the factory, so lean that sometimes if you put the engine on a snowblower it will hunt at full throttle unless you either install a slightly larger jet or put the choke partially on.

 

[Brian123]

I recently transplanted a Harbor Freight Predator engine onto an old vintage ariens snow tho. While most people talk about how smooth and awsome the power is, i am more impresed that my coat, scarf, and hat do not smell like choked exhaust. There is far less smell and emissions coming from the new engine. FAR LESS!!!!!!!!

I notice if you ever zip a throttle on a tecumseh, you will get large dropplets of fuel splashing back out the carb throat before the engine increased speed. On other engines like honda, kawasaki, and basically japanese based engines the carb appears to meter the fuel leaps and bounds better than lets say a tecumseh / briggs. There is not one single drop.

So is the carb the main reason why they burn so horrible? Can I have a fab shop make me up an adapter and simply put a more modern carb on my fleet or tecumseh engines to clean them up?

Probably a more efficient cylinder head, more efficiency more power, less smell since an efficient combustion chamber is burning more gas. More gas being burnt probably means less unburnt gasses which would lead to less emissions. All my small engine equipment has Honda Engines on it except my push mower from 1998 that has a Briggs Engine on it, every few years I have to clean the piston, meaning the Briggs, a few years ago I looked at the pistons on the Hondas and they were free of carbon.

Realize we all love the old equipment, but lets realize the engines were not as efficient. The best bang for the buck, old equipment with a new more modern and efficient engine. This scenario is better for our health and for the environment, also better for our wallet since a modern engine will take less fuel as opposed to an older engine.

 

[wag123]

The OHV engines have a much higher compression ratio, higher than 8.5:1 verses the L-head's less than 6:1, it makes a BIG difference in efficiency, and the carburetors are set to run much leaner for emission certification. Trying to install/adapt a different carb to your old L-head engines would be an exercise in futility.

 

[BlueOvalFitter]

Install a B&S engine.

 

[eljefino]

The Chinese clones run pretty lean from the factory, so lean that sometimes if you put the engine on a snowblower it will hunt at full throttle unless you either install a slightly larger jet or put the choke partially on.

Yup, when I put my chonda on I went 2.5 jets bigger:

One for the E10 gas
One for the air filter I deleted as unneccessary on a snowblower
One half for the lower temp vs the 60'F it was calibrated for.

Having done all that the surge is gone! Power curve of the typical chonda is great too-- when it bogs down it makes more torque and powers through. Tecumsehs, possibly sick, would just stall out. They are a trash motor that survived the longest on snowblowers vs other OPE due to intermittent, low-hours use.

 

[Duffyjr]

I recently transplanted a Harbor Freight Predator engine onto an old vintage ariens snow tho. While most people talk about how smooth and awsome the power is, i am more impresed that my coat, scarf, and hat do not smell like choked exhaust. There is far less smell and emissions coming from the new engine. FAR LESS!!!!!!!!

I notice if you ever zip a throttle on a tecumseh, you will get large dropplets of fuel splashing back out the carb throat before the engine increased speed. On other engines like honda, kawasaki, and basically japanese based engines the carb appears to meter the fuel leaps and bounds better than lets say a tecumseh / briggs. There is not one single drop.

So is the carb the main reason why they burn so horrible? Can I have a fab shop make me up an adapter and simply put a more modern carb on my fleet or tecumseh engines to clean them up?

I have a 1995 MTD with a 5 hp Tecumseh and I have never seen it spit fuel back out of the carb, sounds like you need to adjust it or take it apart and clean it or get a new one off Ebay.

 

[Rand]

build a larger fire before you throw it on top.

 

[Warlord]

When you smell of exhaust it lets others know you’ve been doing work. Mix a bit of castor based 2 stroke oil into the gas for a more pleasant aroma.

 

[walterjay]

Tecumseh was a pretty crude engine. I had one on an old Roto tiller. The instructions said to regularly stop working the engine and allow it to spin at fast idle to cool down.

 

[Slick3914]

There's a reason Tecumseh went out of business...their engines were J.U.N.K

 

[Kruse]

Many years ago, my mom had a riding lawn mower with a Tecumseh engine. It lasted more than 15 years without much trouble. Her next riding lawn mower had a B&S engine that lasted about 13 months, one month longer than the warranty. That being said, an old Tecumseh (Clinton, Montgomery Wards, etc.) engine is something you put on a shelf of your man cave for people too look at and admire, not to use.

 

[kschachn]

There's a reason Tecumseh went out of business...their engines were J.U.N.K

Makes me wonder how I've gotten 22 years out of my snow thrower so far? I've rebuilt the body of the thrower twice but not a thing to the engine, and that's using the dreaded E10 its entire life.

 

[AandPDan]

/\ I'm with you. Mine is 38 years old. Starts and runs great. Never had any engine problems.

 

[Wrenchturner44]

I have had two Tecumseh engines on two different OPE applications. Both ran great. I do think though Tecumseh carburetors were not the best. Both of these engines that I am referring to had float bowl type carbs which were notorious for getting sediment in the bowls and causing the float needles to jam. Briggs engines of the same era had suction diaphragm type carbs and seemed to be less problematic.

Moral of the story is, if you serviced the Tecumseh carb regularly and kept the float bowl clean, they seemed to run great.

 

[wag123]

There's a reason Tecumseh went out of business...their engines were J.U.N.K

There isn't anything at-all wrong with Tecumseh engines (they had a couple of lemons over the many years they were in business, every engine manufacturer has). I was not a fan of the ignition systems they used on their old cast iron block horizontal crankshaft engines.

 

[Lubener]

There's a reason Tecumseh went out of business...their engines were J.U.N.K

That's usually the comment made by someone who doesn't understand small engines and doesn't know how to work on them.