Tecumseh leaking gas

Reply

  #1  
Old 12-11-06, 02:43 PM
Member
Thread Starter
Join Date: Dec 2006
Location: Upstate NY
Posts: 16
Question Tecumseh leaking gas

I have a Simplicity snow blower with a Tecumseh 7hp motor (HSK7). Every year when I bring it out of storage (the engine's run dry of gas in spring) I have a problem with gas pouring out of the carburator. It seems that the problem is the primer assembler, if I crimp the line coming from the primer the leak stops! It seems correct itself after a fair amount of gas has run through it and then it works as designed (gas even comes out of the little hole in the plunger when its leaking). Questions - Is this a common problem? Is there any way to fix it or do I need to buy a new primer assembly?
 
Sponsored Links
  #2  
Old 12-11-06, 07:13 PM
michaeljp86's Avatar
Member
Join Date: May 2005
Location: USA
Posts: 478
I had this problem this spring when I got my lawn mower out, its a 3.8hp techumseh. It wouldnt start like it used to so I looked and it was out of gas and I knew there was gas when I put it in the shed last. I dumped some gas in it then went to put the gas can back inside and when I walked back to the mower gas was running out all over the place and running out the hole in the primer bulb. I took the carb apart and cleaned it out with cyclo carb cleaner and but it back to gether and the problem was fixed. I think its caused by the needle valve onr the float no sealing when the bowl fills with gas so it lets gas flow past it.
 
  #3  
Old 12-13-06, 03:23 AM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
Michael is right, you need to soak and service the carburetor. The problem you're having is related to either the float or the inlet needle & seat OR both. The reason the leakage stops when you clamp off the primer line is because the primer line is also the bowl vent. Without atmospheric pressure (high pressure) the fuel can't possibly leak out but it also can't possibly run...for long. Rebuild your carb with the proper kit and also install a new float and mounting gasket and your woes will cease. Post back with all the engine ID numbers and I'll provide the correct part numbers you will need.
 
  #4  
Old 12-13-06, 07:33 AM
Member
Thread Starter
Join Date: Dec 2006
Location: Upstate NY
Posts: 16
Smile Engine Nos.

Thank You for the help. The specifics for the Engine are:

Model - HSK70
Ser. No. - 130286S (D)
D.O.M. - 4262R

Also, do you happen to know the proper RPM setting at wide open throttle?

Thanks again and have a great Christmas and New Year Season.
 
  #5  
Old 12-26-06, 01:38 PM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
Sorry to leave you hanging, Timmor, I thought I responded to your post but it was a similar one. Tecumseh part numbers: 31840, kit; 632802, float; 31688A, carb to spacer gasket; 27915A, spacer to block gasket. Top RPM is 3600 and idle is 1700.
 
  #6  
Old 01-12-07, 01:33 PM
Member
Thread Starter
Join Date: Dec 2006
Location: Upstate NY
Posts: 16
Tecumseh Carb rebuild - Float question

Float Number 632802 is a plastic float, Tecumseh float 632019 is the brass float that appears to be the one currently in the carb. Is there an advantage / disadvantage for using a plastic one vs. brass? Thanks again for your help!
 
  #7  
Old 01-12-07, 02:20 PM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
Honestly, I'm not sure there is any difference but I've never compared them side by side. Yours calls for the plastic one and if they are indeed the same specs, I'd opt for the plastic...less likely to spring a leak.
 
  #8  
Old 04-11-07, 11:00 AM
fzz
fzz is offline
Member
Join Date: Apr 2007
Posts: 7
Unhappy 3.8 Tecumseh, won't stay running, once leaky primer bulb

Wow! I had to check the post that michaeljp86 wrote a while back to see if I had posted in myself.

I'm having the same problem. Gas leaking out of the primer bulb. Engine will only stay running if the primer bulb is pumped or depressed. I've replaced the plug and cleaned the carb (by spraying carb cleaner while the carb was attached).

The engine is is a Tecumseh 3.8hp engine (sold on a circa '93 Craftsmen 3 in 1 mower). The model number is: Tecumseh TVS90-46016, Craftsmen 143.434312). Also, the primer bulb leaks has resolved itself but the engine still won't stay running.

Someone else suggested replacing the whole float, bowl..etc. with a Tecumseh Float Bowl Assemboy (Tecumseh #730235B) but I can't determine if this will fit my engine.

I have been able to find other kits for the motor. The kits seem to just include a highspeed valve, spring(s) and gasket. An example is this one from Stens: http://www.stens.com/dealernet/catalog.html?sType=3&part=520304

My question should I also replace the bowl, float and primer bulb too? If so, is there a complete kit for this (like the Tecumseh #730235B) assembly or do I have to buy individual components? Finally, are there any tips/advice for someone that's mechanically inclined yet hasn't actually performed a carb rebuild? Thanks in advance!
 
  #9  
Old 04-11-07, 02:32 PM
michaeljp86's Avatar
Member
Join Date: May 2005
Location: USA
Posts: 478
I would try cleaning it really good first, that fixed my problem.
 
  #10  
Old 04-11-07, 03:00 PM
fzz
fzz is offline
Member
Join Date: Apr 2007
Posts: 7
I will give cleaning a try

As far as cleaning goes, are there any pieces I should be paying special attention to? Thanks.
 
  #11  
Old 04-11-07, 04:44 PM
Azis
Visiting Guest
Posts: n/a
You can find the correct part directly from sears.
http://www3.sears.com/
 
  #12  
Old 04-11-07, 08:07 PM
michaeljp86's Avatar
Member
Join Date: May 2005
Location: USA
Posts: 478
Originally Posted by fzz View Post
As far as cleaning goes, are there any pieces I should be paying special attention to? Thanks.
take the float off and the needle valve and up inside where the needle seat is needs to be nice and clean for it to seal good.
 
  #13  
Old 04-16-07, 02:28 PM
fzz
fzz is offline
Member
Join Date: Apr 2007
Posts: 7
Took apart the carburetor

Tons of crud in the bowl. The carburetor gasket didn't make it through the strip down though -- So i'll definitely be needing a gasket kit. As luck would have it I think I also misplaced the dang inlet needle seat so I'll be grabbing one of those too.
 
  #14  
Old 04-24-07, 06:39 PM
fzz
fzz is offline
Member
Join Date: Apr 2007
Posts: 7
Good news and bad news!

First the good:

I purchased a carb kit (tecumseh #631021B) (needle valve, seat, float bowl gasket and washer), a carburetor gasket and a new length of gas line. Total cost for everything: $6

I reassembled and installed the carb but apparently have forgotten how the throttle linkages were connected. I made a best guess, put a couple of cups of gas in the tank, primed her up and she started on the FIRST PULL!!

Ok, now the bad:

I'm currently encountering two problems. When the mower is running it's running really fast. Obviously I don't quite have the right hook up between the govenor and the carb/butterfly and turtle/rabbit lever. When I move the lever between turtle and rabbit I see absolutely no movement of the govenor.

The second problem is that the float bowl is leaking out the bottom (through the highspeed bowl nut. I thought I might have over tightened it, so I tried backing it off a bit. No luck! I pulled the whole nut off and noticed that the washer seemed to be eaten a bit. Almost like the the gasoline dissolved it or something. I tried putting the old washer back on but it still leaks. A couple of questions:

1) how tight should I be socking down the bowl nut?
2) there are two tiny holes in the bowl nut and two tiny holes where the nut threads into the carb. Are these holes supposed to be alighned?
3) I've connected throttle linkage to the throttle lever (turtle/bunny lever) and the governor spring linkage to the middle (of three) holes on the throttle shaft lever. Am I even close?

Thank you to every who has posted on this thread! It's amazingly rewarding to get an otherwise dead engine going with one pull of the starter!
 
  #15  
Old 04-25-07, 11:39 AM
fzz
fzz is offline
Member
Join Date: Apr 2007
Posts: 7
Ok I know what I did

Regarding my last post (and my over-revving engine): I found that this helpful site (http://www.small-engines.com/tecgov.html) had an illustration of the correct hookup for the throttle linkage. Of course my "best guess" was completely backwards. Now my remaining problem is the slowly leaking (weeping) fuel bowl.
 
  #16  
Old 04-25-07, 11:56 AM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
Honestly, I don't know if there is a torque spec to tighten the bowl nut/main jet to. I just use common sense based on the fact that the jet is brass and you're threading into aluminum, both soft materials. If I had to guess the torque it may be around 75 inch pounds. As for the leak, did you remove (scrape) off the old gasket well enough so that it causes no interference with the new gasket? Is the bowl possibly pitted and leaking from a miniscule hole in such? In the hex end of the jet on most jets there may be a tiny ball bearing jammed into the jet. This is used to seal off the factory drilled passageway and have been known to leak. If so, you will need to replace the jet and is Tecumseh part number 632682 and goes for around $5.
 
  #17  
Old 04-26-07, 07:34 AM
fzz
fzz is offline
Member
Join Date: Apr 2007
Posts: 7
Bowl was pitted

Puey61,

You called it! The bowl turned out to be pitted. There was some oxidation which pitted the bottom of the bowl and I guess the carburetor cleaner stripped off whatever bit of crud or paint that was keeping the bowl sealed. I could barely spot the leak with the naked eye. Of course, under a magnifying glass it looked like the Grand Canyon!

One other question: I've read elsewhere that the float should by nearly level when the carburetor is inverted. Mine dips about (say about) 10-15 degrees.

Apparently, I can calibrate the float by using laying an 11/64" drill bit on the side opposite the float hinge and bending the tang that holds the inlet needle spring. Is this true or should I just leave it alone since it seems to be running ok?
 
  #18  
Old 04-26-07, 09:09 AM
Azis
Visiting Guest
Posts: n/a
I don't think this manual covers snow king engines specifically, but the theory and instructions for most procedures will apply.
http://www.cpdonline.com/692509.pdf
 
  #19  
Old 04-27-07, 02:06 AM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
To answer your question, 10-15 degrees sounds about right but using the drill bit trick is good measure to verify the setting. Did you get a new bowl?
 
  #20  
Old 04-30-07, 07:04 AM
fzz
fzz is offline
Member
Join Date: Apr 2007
Posts: 7
touchdown!

Azis, thanks for the very handy tecumseh manual link.

Puey61, I did the 11/64ths drill-bit procedure and readjusted my bowl (it was just slightly off). Bought a new bowl and voila! Mower starts easily on the first pull, runs great with no leaks!

Total outlay:
$0.70 - carburetor gasket
$5.30 - tecumseh carburetor kit (needle valve, seat, float bowl gasket, float bowl nut washer)
$2.19 - fuel bowl
$2.99 - carburetor cleaner
------
$11.18

Doing it yourself with help from friendly and knowledgeable people on the internet: PRICELESS!
 
  #21  
Old 05-26-08, 06:13 AM
Member
Join Date: May 2008
Posts: 1
Please post for me as it is important. I fell guilty for not sharing this earlier.

I had the same problem with a craftsmen lawn mower. (Runs for a few seconds and then stalls out) It has the cast aluminum carburetor with no adjustments. Once you fix the problem, you'll agree that it actually is a pretty clever design. I did absolutely everything (cleaning passageways, checking flatness of top and bottom mating surfaces of carb. etc.etc.etc.)

All you have to do is remove the large flat headed screw on side of carburetor. Inside, behind this screw, is the high speed jet. (A small white plastic molded part with a passageway through it) You blow through it, look through it and its clean, right?? Wrong. The dirt drops down into a recess within the passageway so you cannot see it. When you prime the carb. and start engine it will run, try to pull gas from tank, RE-SUSPEND this dirt which in turn plugs against screen inside this jet, and thus stalls engine. (no gas) All you need to do is poke a hole through screen with small nail or drill, clean with spray, and re-install jet.
Don't even need to take the damn carb. off engine, although you're probably real good at it by now!
The in-line (spinning top shaped) filter (if you have one in the rubber gas line) is really just a strainer (fine screen). The screens in these may not be fine enough to prevent the screen in the gasoline jet from plugging. I put an in-line paper type filter in the rubber gas line. I've read (or been told) that these will not work due to the additional resistance they create on a gravity fed system. It worked great for me. You would want one with enough filter in it and when installed that it would not raise the hose level very much. (The gas tank must be able to gravity feed the carburetor) I had a similar situation with a car one time.
Did everything, finally replaced the needle seat in carburetor just for the heck of it. (Usually you only do this when the float in carb. is sticking) When I removed the seat, it had a screen on it! (What the h---) You tear it off and use an in-line filter (with a paper pleated element). Carburetor manufacturers do this to keep their device clean, itís up to the lawn mower (auto) assembler to remove it and install an in-line filter.

For air, oil, gas filtration, pleated paper filter media (Fram, Purolator, etc.) is the best.
The more filter area, the better. (Doubling your filter area will more than quadruple the usable filter life!!) Filter paper stops microscopic particulate, protecting your engine. One brand, in particular, really gets me. In fact it's hard to believe there full of it when you see that they are 3 times more expensive. (They're in auto parts stores) They have very little filter and in order for them to work (not cause a big pressure drop) is to have large pores in the filter media. The scam is that: when you spend this much money, you'll swear it's great (more H.P.,nah,nah,nah) By the time fine silica sand damages engine, the car will be worn out anyway. (i.e. You'll never notice)

Have a Great Day!

JFC

And if I was a nice guy fixing lawnmowers, you could spray the carb.
with cleaner (make it look new), poke the hole through screen on high speed jet, and charge for whole new carb. and labor. (i.e. ask for your old carbuerator back after you get bill)
 
  #22  
Old 05-26-08, 08:44 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,815
Geez...you think us lawnmower shops are spraying off old carbs and charging customers for new ones? I don't think anyone would get away with that for very long.

Proper cleaning should get this jet area clean. The carb in question is different from the one you're describing though...You've got the plastic bowl carb that's probably as much problem as any other carb tecumseh has made over the years.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes