Carb Help Needed

[McGrew 460]

Hi Guys,  First, I hope everyone had a good Thanksgiving!  We had a big turkey lunch, and then I spent all afternoon on my Raider 10 moving 5 yards of hardwood mulch.   A little background on the tractor, then my question.  The 10 hp Tecumseh was replaced by a 14hp Tecumseh (HH140).  The engine was rebuilt when it was installed several years ago and has had little use since.  The engine runs great, but starting is a bit of an issue.  The engine fires up normally when cold.  Pull the choke, turn the key and it comes to life.  What is odd is that even when fully warmed up, I have to choke the engine to get it to fire.  I had this problem when I first acquired the tractor this Summer, I went through the carb and cleaned it out, and rebuilt the fuel pump.  I adjusted the carb, replaced all the fuel lines and put on a new fuel filter.  I only run non-ethanol gas.  I was taught you never choke a warm engine, but I believe I could spin the warm engine until the battery died without it firing.  But pull the choke, and it fires right up.  What is going on?  The carb is the original Walbro LMH dated 4-1-74.   Is it time for a new carb?  If so, which one?  I see many carbs on EBay, but don’t know if they will work on my Techy without modification.  Most say they fit Kohler.  If this were a V8 with a Holley, I would be a lot more comfortable... Any advice greatly appreciated!  Thanks!  Danny

[Ed Kennell 40,841]

Sounds like air may be leaking in around a worn throttle shaft bore or a leaking carb gasket.     With the engine running, spray those areas with carb cleaner.  If the RPM increases, you have a leak.

[McGrew 460]

Thanks Ed!  I will give it a shot tomorrow.  Danny

[oliver2-44 10,445]

I've never hear of not chocking a warm engine.  However I was taught to that over doing it could easily flood or vapor lock a warn engine. 

i would think a one crank with choke when warm would be OK, just something to not overdo. 

I'll be interested to hear what others have to say about chocking a warm engine.

[McGrew 460]

Oliver2-44, I am not sure where I got that information.  Probably my Dad, as he taught me a lot!  That said, I do believe there is something wrong with the carb.  I can run the tractor for 15 minutes and shut it off for 5 seconds, and it will not restart without choking it...   I too am looking forward to hearing the responses of others regarding choking a warm engine.  It would not be the first time I believed something for years only to find out it was wrong!  Thanks for your response!  Danny

[ebinmaine 71,194]

Danny... While I agree with you that it's a bit odd to need to do that... I hadn't heard of Never choking a warm engine.

 

My Kohler 8 will sit for a couple hours then I need to choke for just a split second.

Trina's 657 with the temporary Briggs 8 is much more needy of the choke.

If it's sits more than a few minutes you need to start it with the choke 1/2 on for maybe 2 to 5 seconds.

My chainsaw is the same way.

 

I'll be interested in seeing the outcome of the testing you do.

 

 

[Pollack Pete 2,273]

My Cyclone Rake that has  a Tecumseh engine does the same thing.Use it for hours.Engine good and warm.Shut it off and I have to apply the choke to re-start it.I don't lose any sleep over it.Not a real big deal for me to slide the choke lever over.Other than that,it runs great.I figure,it ain't broke......don't fix it.

[pacer 3,176]

Not choking a warm/hot eng??? While I dont have any "facts" to back it up but from my some 60+ years of fooling with small engines --- that sounds bizarre!! Of my dozens of engines over the years I maybe had a handful that would start hot. Now mind you, by choking I mean applying he choke very briefly, through 1-2 revolutions. Any thing more than that indeed may indeed indicate a problem. Of my 4 tractors I now have its necessary to do the 'quick' choke to start.

[oldredrider 2,553]

About half of my herd requires a short shot of choke when hot. No big deal.

[McGrew 460]

Thanks to everyone for the responses!  It seems that not choking a hot engine is one more “fact” going down in flames!  I too have been fooling with engines big and small for 50+ years, and this is the first one I have owned one that needed to be choked to start when warm.  Maybe I have been lucky?  Regardless, I will check the carb for air leaks today and report the results.  If there are no leaks, I can live with it!  I agree, if it ain’t broke don’t fix it!  Thanks again for all the responses!  Danny

[Jakeshorsetuff 36]

I have a Kohler that when is cold you have to choke about 1/2 way and fires up with one crank, when its hot you don't have to choke at all. Over the years of working on small engines the ethanol content just eats away the insides of carbs of all brands and they start flooding the engine and won't start, that being said I shut the gas off to all my tractors gravity or pump fed and I don't have to choke when warm.

[McGrew 460]

OK guys, I finally got around to spraying carb cleaner on the carb and gasket.  Absolutely no change when spraying around the gasket, but the engine stumbles when spraying the throttle shaft.  Not a huge stumble, but noticeable.  I guess that is to be expected of a 44 year old carb!  One day I might see if I can insert bushings in the carb body and replace the shaft, but for now, I will live with it.  Or maybe replace the carb with one of the Chinese versions.  Thanks again for all the responses and setting me straight on choking a hot engine!  Danny

[pfrederi 18,407]

I would get a new carb. Many Techy Walbro LME carbs have very little casting around the throttle shaft.  not enough "meat" to drill out and put in  bushing like the Kohler Carbs....

This is the carb on an HH100

[McGrew 460]

Thanks for the information.  The carb on my HH140 looks similar to yours.  I will replace rather than repair.  Do you have any suggestions on which carb to use?  Most of the ones I found on EBay are for a 10 horse engine, although I am sure I can make it work on my 14.  Thanks!  Danny

[ZXT 2,401]

My C120 with a HH120 requires brief choking whenever I go to start it, even when warm. The same is true on my GT-14. 

 

It makes sense that they'd be this way, at least in my mind. When you shut it off and let it sit there, what little residual fuel is present in the mouth of the carburetor (if any) will evaporate, and then there's nothing for it to fire on, and not enough vacuum to pull more gas through the carb. It's not like a down-draft carb on a car where you have some level of fuel seepage into the intake while it's sitting there, or an accelerator pump to give it an extra shot. The choke basically takes the place of the accelerator pump.

 

In your searches, if you come across a fairly cheap aftermarket carb, be sure to post about it. The throttle shaft on mine is extremely worn, and has had some brazing done to it where someone apparently broke the shaft. Like you, every one that I've seen has been for a 10hp, which I'm sure is too small for a 12hp, let alone a 14.

 

Edited December 3, 2018 by ZXT

[McGrew 460]

ZXT, Thanks for the reply.  I did an EBay search for “tecumseh 14HP carburetor”, and hit pay dirt.  Well sort of...  They have a ton of carbs listed for engines from 10-16 HP.  The prices ranged from $10-15.  Certainly cheap enough!   Every one of the carbs appear identical in the pictures.  I am sure I can make one work, but there are several things I don’t like.  One, the bowls are plastic.  And the fuel inlet appears to be a nipple on the bowl.  My engine uses a diaphragm fuel pump (the old metal version) that attaches to  the side of the existing carb with 1/8” NPT.   I could make it work, but it would not be as clean as the original design.  I would have to make a bracket to mount the fuel pump, and run a hose from ithe male 1/8 NPT to the carb.  I could also do away with the old fuel pump,and buy one of the new versions.  Until something better comes along, I will live with what I have.  Let me know if you find anything.  Thanks!   Danny

[McGrew 460]

ZXT,  I have been thinking about your last response, and wanted to post a follow up, and a thank you. What you said about the lack of an accelerator pump in the carbs on these tractors is absolutely correct.  I had never given any thought to that.  Almost every carb I worked on (and it has been many) all have accelerator pumps.  That makes a huge difference in how well an engine starts.  Your reasoning is spot on.  Thank you for pointing that out!  Danny

[ZXT 2,401]

No problem! I'm not sure if my logic was correct, but it at least makes sense in my head. 

 

I need the weather to cooperate... It's rained just about every day since I bought my C120 and I havent been able to run it since the day I brought it home!