Custom engine

[bob58o]

Trying to run stock jets in the carb without the stock air box / restrictive exhaust you are going to be lean. You could drill out the jets. Or put stock components back on. I vote for stock.

Since the day of the 212, I dont think Techumsehs are worth putting more than $25 into.

If you can tune a carb, get the jets out. I think one is in the bowl bolt, if I remember right. I can check my old thread to see what sizes I used for the terrible intake and exhaust I made.

 

[Rat]

I did swap the exhaust on it should I go back to stock? I’m going to play around with it and find out and it’s powering a mini four wheeler

Again WHAT IS THE EXHAUST? [As in show a pic]

I wouldn't necessarily put the stock back on, but when you change the exhaust flow, you consequently change the intake flow needs.

A less restricted exhaust means more air can and will pass through the engine... everything is relative and interconnected.

The faster and more exhaust gas you can evacuate the more air the engine can draw in so the fuel rate must change to match or you go lean...in your case too lean to run. An air filter should help, but if it's that far lean it likely wont correct unless its a really restrictive one.

I ran into similar (expectedly) with my newly acquired Ducar 212 when I stuck a straight pipe on it.
I took a dirty old round Briggs filter, torched the paper out of it making it just a cage to put the prefilter on and put one of those aluminum velocity stack filter adapters... boom it runs just like that but needed further tuning of course

 

[Abe]

I don’t have the any airbox or anything

 

[Abe]

And don’t have a picture of the exhaust but once I get home I’ll send it

 

[bob58o]

I think I drill the pilot jet to 0.018”
I kept making the main bigger. I think I ended up at 0.051”

Here is a great breakdown of the carb and jets.
Also, this little bugger of a hole is notorious for clogging.

Disassembly, Cleaning and Repair of Tecumseh Carb 640017

outdoorpowerinfo.com

 

[bob58o]

This was just for fun. The video says I opened the jet to 0.055” from like 0.035” after changing intake and exhaust. Not sure it was tuned properly. I had to increase jet size way more than I thought I’d have to.

 

[Rat]

I don’t have the any airbox or anything

I won't use a stock airbox just because the are stuffy and in my way... same for stock fart boxes

 

[Rat]

This was just for fun. The video says I opened the jet to 0.055” from like 0.035” after changing intake and exhaust. Not sure it was tuned properly. I had to increase jet size way more than I thought I’d have to.

View attachment 144980View attachment 144981

The main in my Ducar measured at 030 (the bit slid through without resistance or wiggle room)

 

[bob58o]

The main in my Ducar measured at 030 (the bit slid through without resistance or wiggle room)

The Tecumseh has this terrible twisted intake manifold. I tried to port match and knock down edges in the casting. I don’t think fuel atomizes well in there so I just kept giving it more jet.

 

[Rat]

The Tecumseh has this terrible twisted intake manifold. I tried to port match and knock down edges in the casting. I don’t think fuel atomizes well in there so I just kept giving it more jet.View attachment 144984

Good God Man!!!

Basically the intake is too long and by switching the exhaust the intake pulse to carb time is tossed out if whack.

I can make way better (short or long) out of steel scrap!!!
Hell one of those 125 Honda dirtbike clone intakes would likely be better than that trash despite it would need cut and booted together to get the carb angle correct (unless you have the means to TIG sand cast aluminum)

 

[Abe]

What would happen if I just got rid of the intake manifold and just attached the carb? And tomorrow im ill mess with the jet

 

[bob58o]

You’ll need some type of angled manifold because these engines seem like they were built forgetting about the carb. Then they routed the carb manifold around the exhaust because they had no space.
(This might be on purpose to keep intake charge temps high so the fuel stays atomized.)

Tecumseh Powersport 6 HP OHV build

Many moons ago, I raced go karts and I ran Tecumseh engines. I started out running modded small block HS50's and later moved on to big H50's. When the Animals came out, Tecumseh had a Motorsports version of the OHV 195cc engine that had a billet rod, high compression head, stainless valves with...

www.diygokarts.com

 

[Rat]

You’ll need some type of angled manifold because these engines seem like they were built forgetting about the carb. Then they routed the carb manifold around the exhaust because they had no space.
(This might be on purpose to keep intake charge temps high so the fuel stays atomized.)

Tecumseh Powersport 6 HP OHV build

Many moons ago, I raced go karts and I ran Tecumseh engines. I started out running modded small block HS50's and later moved on to big H50's. When the Animals came out, Tecumseh had a Motorsports version of the OHV 195cc engine that had a billet rod, high compression head, stainless valves with...

www.diygokarts.com

View attachment 144987View attachment 144988

What an idiotic sh!t design

Would have made more sense to have had the studs positioned horizontally and done a set up a little more like a Briggs flathead which uses very close together ports.

No surprise Tecumseh went belly up making stupid designs like that.

I will say their 2cycle 196 is a brute that if given the standard procedural tuning and a few upgrades is a very scary engine

 

[Abe]

Is the fuel jet the one that screws in horizontally? I have seen a lot of people get the carb with the adjuster at the bottom and that seemed to fix there issue

 

[Rat]

Is the fuel jet the one that screws in horizontally? I have seen a lot of people get the carb with the adjuster at the bottom and that seemed to fix there issue

The main jet is the one screwed into the carb in the biddle of the bowl (above the bolt that holds the bowl on when theres a single center bolt)

The pilot (low speed jet) I'm not sure on that carb because I'm not hands on familiar with that specific turd. All the carbs for the GX, GX clones, Tillotson, Ducar, Predator, etc use a press fit plastic plug with a brass nozzle in it wedged under the idle screw.

I know nothing of any carb with an adjustment under them however the air/fuel bleed adjuster is always horizontal while idle speed adjuster screws can be at a slight angle up or down depending on the manufacturer although are also most often horizontal.

 

[Denny]

Haven’t you guys ever heard of a tunnel ram? That is basically what that is. Gasket match it, smooth out the inside with a long carbide burr on a die grinder. Do not polish it leave it rough. And richen up the mixture. Put the air filter back on or an air filter of some sort.

 

[bob58o]

Main jet is the bowl drain bolt.


Pilot jet seems to be this one, that screws in horizontally.





I’m not sure if an adjustable jet will fit in your carb or not.

 

[Rat]

Only a Tecumseh would be set up so convoluted

 

[bob58o]

If the techumseh carb with adjustable jet fits your engine, that is an option. I’ve never tried an adjustable jet.

I often recommend the PZ19 carb for techumseh because they are more adjustable. Swapping jets is harder than turning a screw, but if getting a different carb I wouldn’t get another techumseh carb. You may need a jet kit with the PZ19 (or drill bits). The intake manifold and exhaust might require larger than stock jets in the PZ19 as well

Honestly, just hog out that main jet you have to 3/64” with a drill bit.

It’ll get it going unless your air density is much different than 600 ft above sea level.

Insert drill bit here.

 

[bob58o]

I didn’t watch this video so forgive me if the video is trash.

Save your receipts.
I accept all credit for your successes, but any failures are entirely on you. lol

You may have to drill the manifold a bit to make the pz19 fit if you go that route.

(I did end up watching it. He starts out saying it’s a direct bolt on, then goes on to make minor modifications.)