Tecumseh won't run past half throttle

[Roadrunner123]

Thanks for the reply. Ok so I made sure the high and low needles are in the correct position. Did that before today's previous post. The breather is something I've been meaning to check so thanks for reminding me. Also what product did you use to seal the welsh plugs that would be impervious to gas?
As far as the nylon ball is concerned, all I see is that it moves up and down and it took two magnifying glasses and a high powered light to see this. There is no way to remove it that I can see and it's not listed on any parts lists.

[Roadrunner123]

I pulled off the breather and cleaned it. One question I have is concerning the reed valve. This breather is once piece and I can blow through it fine but I'm not sure if the reed vavle is working properly. I can stick to small pieces of paper in between the reed and the body with very little resistance when I pull back. Should the reed be right up against the body do you know?

[bgsengine]

I pulled off the breather and cleaned it. One question I have is concerning the reed valve. This breather is once piece and I can blow through it fine but I'm not sure if the reed vavle is working properly. I can stick to small pieces of paper in between the reed and the body with very little resistance when I pull back. Should the reed be right up against the body do you know?

Not necessarily, reed just needs to be able to seal (for the most part) when crankcase vacuum pulls it closed, there's typically a little bit of air gap - one way to test , if you can find a piece of rubber hose big enough to seal around the breather (or you can install it and if there's no oil / low oil, or a dipstick tube) you can blow air through and out the breather then try and suck the same amount of air back - the breather should "flap" closed making it much more difficult to suck air out of crankcase - Breather is there to maintain a lower pressure in the crankcase as the piston moves up, it pulls a vacuum, it helps keep oil (and oil seals) from blowing out when the piston comes down on power and intake strokes by letting air out, then as piston goes up (compression/exhaust strokes) it pulls valve closed to create a negative pressure in the crankcase. It is not common to see them fail , and when they do, the typical obvious symptoms are oil pushing out past the oil seals, crankcase gaskets blowing out, and oil blowing out the crankcase breather (and if stuck closed or plugged, symptom is, it blows the oil seals out frequently)

[Roadrunner123]

yes I had the same thought as far as testing goes but haven't found a hose the proper size. I did try using a piece of pvc and could hear the flap opening and closing but the seal created by the pvc wasn't that great so I was sucking air in and couldn't tell if the reed was leaking.
One other thing I was thinking about was what you said about the engine running at 3600 rpm with no load and the idle circuit feeding it. Once I reinstall the carb and if problem still exists once I get it up to full speed with the high speed jet closed I will close the low speed adj and if it still runs I know I'm missing something. I want to seal that high speed welsh plug but not sure what the best sealant to use. I asked Arkie what he used but he hasn't responded yet. I do have gasket sealant and that may work but I haven't investigated it yet.
Thanks for your response.

[Arkie]

You also need to make sure that the breather assembly on the engine is back checking normally or not blocked. It will upset the pump pulses to a diaphragm type carb.

Huh? these tecumseh diaphragm carbs don't have fuel pumps integrated - they're gravity fed. But for a fuel pump (separate from the carburetor), good point.

Right: About gravity fed to this carb but just need to make sure that it's not completely blocked or completely open. (so as not any little bit of upset to the intake air flow thru this carb throat as the throttle butterfly is coming off idle for the transition to High suction thru the carb throat) Since the H jet is not having any affect, it's being bypassed or one of the transition ports in the carb or ????. Surely it's NOT porous casting or cracked?????????

Also I noticed he indicated in a previous post he did not see or find any float carbs that has both jets adjustable.
This link has several, the jet on the bottom of the bowl is the H jet.
https://www.ebay.com/b/Tecumseh-H35-Car ... 7023422684

The epoxy that I use for permanently sealing welch plugs is Brownells Acraglass gel that I happen to keep for other purposes such as glass bedding rifles. (cost about $25-30 a kit but also has a long shelf life) It can be removed by heat such as a soldering iron. Takes it about 24 hours to cure at low humidity at 75 degrees.

As a temporary test you can use JB weld or even fingernail polish and if you get a good run you can go back and re-do the plug. I think I seen several different kits for that diaphragm carb on-line with the welch plugs. at about $12 per kit.

Also when you seen that check ball move up and down did you see if the port is open (not clogged) thru the ball's orifice hole?

[Roadrunner123]

what the heck was I thinking about the two jets!!! I'm getting old, I totally forgot that the high speed jet is on the bottom of the bowl. I will seal the welsh plug and put everything back together after another inspection for any cracks or imperfections. If all fails I will look for a bowl carb.
Thanks

[Arkie]

I seem to think maybe I had to keep a heads up on Bowl type Tecumseh carbs CHOKE lever configuring due to the different types of breathers used so as the choke lever could be operated with the breather in place. Also measure your C-C mounting bolts. (some have a non standard spacing on the manifold)

A jaw dropper will be if you install a float carb and it still acts the same way.

I had a Tecumseh with similar issues that I won't forget. Kept flogging the little float type carb.
Engine would idle but not rev up smooth and sputter. Long story short. It was ignition. Was a bad points type magneto that was failing at higher rpms.
I've seen erratic condensers do about the same.

You said you like a challenge. Tecumsehs like a challenge also sometimes. That is another reason they get bad mouthed. They seem to like to play with your brain.

Stay patient.

[Roadrunner123]

I conversed with the people that sell the carbs from the link you sent me and they said they didn't have a carb that would fit my engine. I found one I thought looked exactly like my linkage and asked them what the distance was cc and they wrote back and said they didn't have that info. I sent them all my info. and they replied nothing would fit.
I'll keep looking.

[38racing]

early on you said you pulled the head to check valves but did yu actually check valve clearance? I had a 5 hp tec on an ariens blower. it would startand run but die when auger was engaged in snow. it was due to no clearance onthe exhaust valve.

[Arkie]

Some more Tecumseh carb info:
Scroll down to the bottom of the page for different types of selection links info part numbers updates, etc.

http://www.tecumsehcarburetorguide.com/ ... ification/