Tecumseh HH100 carb problems?

[ArturHawk 174]

Good morning! At least it would be, but i'm going crazy trying to get the carb adjustment right on my Raider 10 with a HH100 10hp engine.

 

I've pulled the carb and cleaned it a few times, adjusted float to 11/64" (.171"), new fuel filter, reset idle adjustment needle to 1-1/4 turns and high speed to 1-3/4 turns out. Everything looks good, adjustment needles don't have rings, float needle seals properly (when there's no dirt).

 

I start the tractor, then tune the idle until it sounds good (is in leaner and out it richer?). Then I bring it to high rpm and tune until it sounds good as well, then make a little richer so it doesn't go lean on me when under load.

 

The problem is after running it for a little bit it will start to die on me (usually under load) and i'm back at the adjustment needles fiddling around to get it running right. One day it will be running fine after adjusting it once or twice while mowing, then i'll be out a couple days later and it's rough again.

 

Any ideas what to look for?

[ArturHawk 174]

I forgot to add I have been using the manual in this link as my reference.

 

https://www.manualslib.com/manual/408796/Tecumseh-Hh100.html?page=8#manual

[roadapples 6,981]

New fuel lines???

[wallfish 15,918]

3 hours ago, ArturHawk said:

Any ideas what to look for?

1)Spray carb cleaner around throttle and the gasket areas with the engine running. If it changes rpm when you spray then it's sucking air where it shouldn't.

2)Remove the float and shake it to see if there's a pinhole and gas inside if it.

3)You can change the carb to a Kohler type Carter N or Walbro.

[ArturHawk 174]

1 hour ago, roadapples said:

New fuel lines???

All lines just replaced a month ago.

[ArturHawk 174]

1 minute ago, wallfish said:

1)Spray carb cleaner around throttle and the gasket areas with the engine running. If it changes rpm when you spray then it's sucking air where it shouldn't.

2)Remove the float and shake it to see if there's a pinhole and gas inside if it.

3)You can change the carb to a Kohler type Carter N or Walbro.

1) I'll try this when I get home. Gaskets looked good, but it doesn't hurt to try.

2) Float was good. Made sure to give it a good shake when I set the height.

3) This is my last ditch option. I'd prefer to make what I have work.

[Tractorhead 8,607]

 

My first thing on such machines are allway‘s 

 put an inlinefilter into fuelline, to see if some dirt or rust out of the Tank clogged the carb again?

check Tank cap if ventilation is clogged

at least @wallfish advice, spray arround on idling Engine with carb cleaner or wD40 if nothing other available

and listen if engine changes it‘s sound.rmp drop or raise.

 

Edit

on my HH60 on the right side of Carb flange i got a rpm change,

after closer investigation i found it loosened the Screw.

I just have to retighten it and all was done.

 

 

Edited August 31, 2020 by Tractorhead

[cafoose 3,135]

Throttle shaft bushing?

 

 

[ArturHawk 174]

Took a while to get time to work on it. The throttle shafts are solid. I sprayed starter fluid around the carb and got some rpm changes. 

When I got the new engine I used the carburetor of the old one because the PO said the new one leaked and I knew the old one was good.

 

What I didn't realize was the spacers between the engine and carb were two different sizes. Using my old carb and the new spacer made the float bowl touch the breather and prevented me from getting a good seal. The spacer accounts for the difference in offset of the float bowls on the two carbs.

 

While I had everything apart, I also took the head off, cleaned the chamber and checked the valves. The exhaust only had a .016" gap, so I increased it to .020" to meet spec. Probably won't make much of a difference, but it makes me feel better.

 

Once everything was back together, it fired up with no problems. I still get a stumble every once in a while. It's just a single hollow "fup" sound every once in a while that I can't seem to tune all the way away. I redid the starter fluid test and didn't find any leaks.

 

It was too late tonight to go for a joyride. I hope to see how it handles working under load tomorrow. I need to mow my grass!

[ArturHawk 174]

Ok, so a lot happened between my last post and this one, but I wanted to report my findings in case someone else has issues. Techumsehs don't seem to have as much info around as the Kohlers.

 

First off, I ran into an issue where gas was squirting out of the side of the carb! I've had it leak out of the front, but not literal jets of gasoline shooting like a water pistol directly onto my muffler! 

 

Gas was coming out of the tiny hole right below the ridge...I didn't even know there was a hole there before.

 

My first thought was to check the float needle for garbage...and that was the problem. I had replaced all fuel lines and added an in line fuel filter when I did the engine swap. Maybe there is some dirt in the fuel pump that i've been freeing up with use.

 

I also learned I was not using full throttle. The cable sleeve was hitting the side of the throttle lever when engaged and it wouldn't pull the lever to full throttle position. 

 

I also adjusted the clamp for the throttle cable so when the cable is pulled to full throttle, the governor linkage would rest against the stop screw. Previously, I had set it so when the throttle cable was in the idle position, the linkage would let the carb plate close against the idle rpm screw. This new setting keeps the carb slightly open when the engine is off, but it closes against the idle rpm screw when it is on due to vacuum in the carb. The engine also runs at a higher rpm at full throttle (no way to check actual rpm right now, just going by ear) and sounds much better.

 

I'm sure trying to tune the carb previously with the high speed screw and not having the tractor at high speed was giving me some issues.

 

Back to tuning...still getting that same "fup" noise every once in a while. Also happens when i'm just driving around. More so driving downhill than on level ground. It goes away when the engine is asked to work...pulling loads uphill, mower deck engaged, etc. I am also no longer having problems with stalling/stumbling under load.

 

At this point, starting has a very interesting procedure. When cold, full choke, crank, at first "pop" go down to choke in lowest or second lowest position.

When warm, full choke, crank, at first "pop" turn choke off as fast as possible. Will not start without choke to get first cylinder fire.

 

When warmed up, it runs mostly fine without choke, but sometimes likes to be in lowest choke setting. I'm going to try to richen up a tiny amount and see what happens.

 

Big question! Do you guys tune the idle mixture screw first, then full speed? Or do you tune full speed mix, then idle?

[ebinmaine 63,079]

On 10/13/2020 at 9:27 PM, ArturHawk said:

report my findings in case someone else has issues

@ArturHawk

 

How's this tractor been running?

Were the adjustment issues fixed?

 

[Handy Don 10,586]

On 10/13/2020 at 9:27 PM, ArturHawk said:

tune the idle mixture screw first, then full speed? Or do you tune full speed mix, then idle?

Yes, I see this was a really old thread.

 

Warmup. Then main, idle, high rev limit, idle limit. 

 

My HH60 won't go chokeless unless thoroughly warmed up and rarely in real cold weather.

Just got an HH100 and still in the cleaning stage so haven't tried to run it yet.

 

That hole you are pointing to is intended to provide the carb with an atmospheric air pressure reference letting the carb properly meter fuel into the jets (deep technical explanation deleted ) -- it is NOT a fuel path. Fuel coming out of there means your float and or needle valve are not keeping the fuel level at the proper height inside the carb and the fuel pump is just pushing the fuel out and/or another air passage in the carb is blocked. Not good at all!

Edited September 7, 2021 by Handy Don

[lynnmor 6,765]

4 hours ago, Handy Don said:

That hole you are pointing to is intended to provide the carb with an atmospheric air pressure reference letting the carb properly meter fuel into the jets (deep technical explanation deleted ) -- it is NOT a fuel path. Fuel coming out of there means your float and or needle valve are not keeping the fuel level at the proper height inside the carb and the fuel pump is just pushing the fuel out and/or another air passage in the carb is blocked. Not good at all!

 

I believe that the float and/or needle valve was the problem from the beginning.