H60 Tecumseh runs very poorly - Snowblower Forum : Snow Blower Forums
Reply
 
LinkBack Thread Tools
post #1 of 28 Old 12-11-2014, 05:44 AM Thread Starter
Senior Member
 
Join Date: Dec 2014
Location: Cape Cod, MA
Posts: 154
Post Thanks / Like
Thanks (Given): 5
Thanks (Received): 11
Likes (Given): 9
Likes (Received): 30
H60 Tecumseh runs very poorly

I have an old Ariens, probably late 60s or early 70s. It has a well worn H60 Tecumseh. It fires right off but runs poorly, firing very intermitantly and finally stops. It restarts right off and does the same thing.

First, let me say that I am a boat mechanic with 40 years in the business; and I have some fairly extensive personal experience with small four stroke power equipment. This one has me temporarily stumped, though!! What I CAN say:

Fuel system: Tank is clean, filter is clean, good flow available to carb. Carb has been cleaned and preset adjustments to 1 1/2 open. From there, I have messed with them either way, to no avail. Sitting at rest, not running, there is no overflow. Pulling float bowl off and operating float by hand, gas flows and stops as it should. Float level is parallel to housing. No fuel trapped in float. New mounting gaskets were installed and they are oriented correctly.

Ignition system: Tried three different plugs, including one brand new one. Condenser leak tests excellent on a magneto analyzer. Points have been cleaned like new and adjusted to .020". When engine runs, an inline neon spark checker never falters, even when engine is clearly not firing.

Fuel: No water in gas that is visable. It IS ethanol fuel but it's only a few weeks old.

Power head: 120 psi compression. Valve clearance about .008 on both valves.

Spark plug condition: Engine will run correctly for about 10 seconds on a clean plug; then it starts its bad stuff. Pull the plug and it is pretty black, right away.

I have an H80 of the same vintage that will do the same thing, but it takes half a driveway of blowing, before it happens. Any ideas how to trouble shoot this any further? I was thinking a leak down test, which I do have tool to do it with....Also, I will probably take the carb off again and check it over again; however, I am confident it's clean. So I would be looking for some other exotic problem, which some of you guys may have seen?

Last edited by bwright1818; 12-11-2014 at 05:53 AM.
bwright1818 is offline  
Sponsored Links
Advertisement
 
post #2 of 28 Old 12-11-2014, 06:10 AM
Senior Member
 
Join Date: Nov 2014
Location: Buffalo, New York
Posts: 257
Post Thanks / Like
Thanks (Given): 2
Thanks (Received): 6
Likes (Given): 0
Likes (Received): 3
Send a message via AIM to SteelyTim
First thing I do in this situation is grab a spray bottle of gas, shoot it a couple times into the carb, and then see if I can get it to run decently well while slowly spraying gas into the carb with a very light spray on the trigger. If it'll run that way, you'll know it's something with the carb.

If it's got a primer bulb, shoot carb cleaner into the primer hole (remove the primer hose and spray in there) to see if you can get gas coming out of the topside of the carb through the primer hole in the carb throat.

If you've got the time and are sick of screwing with the carb, pick up a carb for around $30 or so on ebay, slap it on and be done with it.

To me, H60s are a lot easier to get running than H80s when they have fuel issues. Let us know what you find.

Last edited by SteelyTim; 12-11-2014 at 06:21 AM.
SteelyTim is offline  
post #3 of 28 Old 12-11-2014, 06:35 AM
Senior Member
 
Join Date: Feb 2014
Posts: 864
Post Thanks / Like
Thanks (Given): 0
Thanks (Received): 17
Likes (Given): 0
Likes (Received): 79
Quote:
Originally Posted by bwright1818 View Post
I have an old Ariens, probably late 60s or early 70s. It has a well worn H60 Tecumseh. It fires right off but runs poorly, firing very intermitantly and finally stops. It restarts right off and does the same thing.

First, let me say that I am a boat mechanic with 40 years in the business; and I have some fairly extensive personal experience with small four stroke power equipment. This one has me temporarily stumped, though!! What I CAN say:

Fuel system: Tank is clean, filter is clean, good flow available to carb. Carb has been cleaned and preset adjustments to 1 1/2 open. From there, I have messed with them either way, to no avail. Sitting at rest, not running, there is no overflow. Pulling float bowl off and operating float by hand, gas flows and stops as it should. Float level is parallel to housing. No fuel trapped in float. New mounting gaskets were installed and they are oriented correctly.

Ignition system: Tried three different plugs, including one brand new one. Condenser leak tests excellent on a magneto analyzer. Points have been cleaned like new and adjusted to .020". When engine runs, an inline neon spark checker never falters, even when engine is clearly not firing.

Fuel: No water in gas that is visable. It IS ethanol fuel but it's only a few weeks old.

Power head: 120 psi compression. Valve clearance about .008 on both valves.

Spark plug condition: Engine will run correctly for about 10 seconds on a clean plug; then it starts its bad stuff. Pull the plug and it is pretty black, right away.

I have an H80 of the same vintage that will do the same thing, but it takes half a driveway of blowing, before it happens. Any ideas how to trouble shoot this any further? I was thinking a leak down test, which I do have tool to do it with....Also, I will probably take the carb off again and check it over again; however, I am confident it's clean. So I would be looking for some other exotic problem, which some of you guys may have seen?
see this thread

https://www.snowblowerforum.com/forum...ry-solved.html

there is a hidden passage in the Tecumseh carburetors that is very difficult to clean, see this thread. also there is a very tiny small passage in the main jet that feeds the idle circuit, it takes a .020" pin to clean it, a sewing pin. until you get all those passages cleaned out the carb many act up. there are 3 tiny idle/off idle discharge holes under the side welch plug, make sure they are clear- and there is 3 air bleeds in the entrance of the carb on choke side, make sure they are clear. best thing to do it soak the carb in a mixture of gasoline and mineral spirits for about a day or 2, then blow all those passages out with compressed air. you many have to drill the carb plug to get at the hidden idle jet passage and poke it out, then reseal it somehow.

or, just get a complete new or good carb somewhere.

it may also have intermittent spark problems i.e. points/condenser

on the Tec. engines, there is a filter screen in the bottom of the gas tank on the petcock, remove the entire petcock assembly and clean the screen- or remove the screen entirely and put an inline filter in.

on many of them the petcock itself is blocked with gunk and dirt.

old fuel lines on these machines disintegrate and the rubber pieces come through the line and clog up the carb.

you did put a needle/seat in, and check the float to make sure it's not filling up with gas inside ?

a quick carb rebuild/kit and quick cleaning usually gets these going, but if problems persist, EVERY PASSAGE MUST BE CLEANED- there's no way around it




just say NO to Chinese made ANYTHING !
1967 S-242 Snowbird 4/24
AMF Dynamark Luminaire 5362 8/26 3-stage
Craftsman Drift Breaker 10/32 3-stage
Gilson 55012 8/26 gear drive
Ariens 910010 8/32
Cub Cadet 268 8/26
Yard-Man Snowbird 7040-0 5/22
Ariens 10M-L35 3.5/24
New Holland/Gilson Unitrol 8/26
(2) AMF Polar Bear 7/26 3-stage project/parts machines

Last edited by greatwhitebuffalo; 12-11-2014 at 06:37 AM.
greatwhitebuffalo is offline  
post #4 of 28 Old 12-11-2014, 06:58 AM
Senior Member
 
Join Date: Dec 2013
Location: Massachusetts and Maine
Posts: 792
Post Thanks / Like
Thanks (Given): 3
Thanks (Received): 27
Likes (Given): 0
Likes (Received): 42
BrigTrht1818
Don't overlook the cap vent on the tank, particularly if it is the older steel tank cap. The vent hole in that type cap gasket is a pinhole in cardboard. Try running with the cap off to see if you are getting a vacuum lock. It definitely sounds like a fuel supply problem. MH

1960 Ariens 45-10M
1961 Ariens 10M55
1977 Ariens 22000
1972 Ariens 10000
1990 Ariens ST724
1987 Toro 724
Murray Ultra 522
MTD Single stage
8 hp MTD hybrid plow
motorhead64 is offline  
post #5 of 28 Old 12-11-2014, 05:50 PM Thread Starter
Senior Member
 
Join Date: Dec 2014
Location: Cape Cod, MA
Posts: 154
Post Thanks / Like
Thanks (Given): 5
Thanks (Received): 11
Likes (Given): 9
Likes (Received): 30
Talking

Quote:
Originally Posted by motorhead64 View Post
BrigTrht1818
Don't overlook the cap vent on the tank, particularly if it is the older steel tank cap. The vent hole in that type cap gasket is a pinhole in cardboard. Try running with the cap off to see if you are getting a vacuum lock. It definitely sounds like a fuel supply problem. MH
Thanks to all! The gas cap was a great idea....but, coincidentally, I had just put a new one on during all this, because a critter had chewed on it. At any rate, I can pull the new fuel line off the carb, hold it over a container, open the fuel valve and gas flows enough to run a small car engine.

I do know about the tiny passage in the main jet, as well as I am aware of the by pass holes under the welch plug. I rechecked the tiny jet in the main jet last night, with a bristle of a wire brush. It was okay. I have to admit that also last night, I reset the high speed jet to 1 1/2 again, just as a check. However, it didn't feel real difinitive when it bottomed out. Maybe something's going on there....something split and cracked, maybe. Although I can make it go too lean or too rich by messing with that needle, there does still seem to be some sort of fuel deal going on. If it were sucking oil around a loose valve stem, I don't THINK it would be fouling a clean plug within the seconds that it does, right?

I bet, in my life time, I have cleaned about 500 carbs. Seriously. But I know I still may have missed something. The older you get, the more you realize how dumb you really are...at least, I do.

I hope to mess with it again, this weekend. Thanks again! Keep those ideas coming!
bwright1818 is offline  
post #6 of 28 Old 12-11-2014, 06:12 PM
Senior Member
 
scrappy's Avatar
 
Join Date: Dec 2014
Location: New Jersey
Posts: 550
Post Thanks / Like
Thanks (Given): 6
Thanks (Received): 41
Likes (Given): 42
Likes (Received): 98
My 2cents is weak spark. I never trust the neon type. Have had this adjustable gap Thexton for 20 plus years. My dads 1967/8 Tec will show 20kv with hand pulled and spark plug removed.

This little tool has worked on cars trucks quads old harleys and it always shows the true spark. always a blue color spark, if yellow it's weak.

Also with points, I have found the points have to be free of oil & grease..



scrappy is online now  
post #7 of 28 Old 12-11-2014, 06:45 PM Thread Starter
Senior Member
 
Join Date: Dec 2014
Location: Cape Cod, MA
Posts: 154
Post Thanks / Like
Thanks (Given): 5
Thanks (Received): 11
Likes (Given): 9
Likes (Received): 30
I didn't mention that I also have an open gap checker...one that looks like a spark plug with the ground electrode removed and an alligator clip, to hook it to ground. On that test, the spark is reliable and blue. I actually took the points right out and carefully refaced them. I do this all the time on my own stuff and have great success with it. I then reinstalled them and reset them. This caused zero change in behavior of the engine. I admit that it SOUNDS as if the ignition is clearly dropping out sometimes. But again, the neon remains steady AND BRIGHT. The funny thing about single cylinder engines is that it's all or nothing. There is no comparing compression readings or doing a balance test! They can be tougher than muliti-cylinder engines because no matter what the problem is, it's either firing or not! That's one reason I will sometimes resort to the neon checkers; but I agree, that is only after an open gap test.

The funny thing with this neon test is that, usually, if the plug is fouling, the KV will go down and you can kind of see and interpret that, in the intensity of the flash. THIS flash remains bright, whether, skipping or not. Normally, that would mean lean misfire...but the plug comes out black and sometimes quite wet. I do have a squirt can with gas in it. I guess I should try that, even though I was thinking too rich.

This old blower is probably not worth the powder to blow it to ****....but now I HAVE to know the answer!
bwright1818 is offline  
post #8 of 28 Old 12-11-2014, 06:59 PM
Senior Member
 
classiccat's Avatar
 
Join Date: Mar 2014
Location: Albany, New York
Posts: 1,741
Post Thanks / Like
Thanks (Given): 231
Thanks (Received): 199
Likes (Given): 2041
Likes (Received): 517
I recently had similar problems with my HM80; started-off strong at 1 1/2 turns-out and started running like butt when warm...Plugs foulin and all of that mess. Once I leaned-out the main mixture valve (bowl) 1/2 turn (from 1 1/2 to 1 turn out), it ran strong. ...that was before I ripped the head-off

You sound like you know this but just in case...make adjustments on a warm engine & do 1/8 turn at a time and wait for the engine to respond.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
('89 Toro 824)

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
('70 Allis-Chalmers Tracker-7)

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
('80 Toro 724)

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
('71 Ariens 910965 SnoThro 524)

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
('87 Toro 38150 826)
classiccat is offline  
post #9 of 28 Old 12-11-2014, 07:08 PM
Senior Member
 
Join Date: Dec 2013
Location: Massachusetts and Maine
Posts: 792
Post Thanks / Like
Thanks (Given): 3
Thanks (Received): 27
Likes (Given): 0
Likes (Received): 42
bwright1818
I would have to know, too. I would pull the head and eyeball the state of the combustion chamber. It may be in severe need of decarbonizing. If your plug is fouling in such a short run, everything is black in there. I would also adjust your float to a slightly lower setting...it should be a little lower than level to insure it is not flooding the cylinder. While the head is off, see if you have excessive wear on the valve guides which is not uncommon on older H60 engines. MH

1960 Ariens 45-10M
1961 Ariens 10M55
1977 Ariens 22000
1972 Ariens 10000
1990 Ariens ST724
1987 Toro 724
Murray Ultra 522
MTD Single stage
8 hp MTD hybrid plow
motorhead64 is offline  
post #10 of 28 Old 12-11-2014, 07:34 PM
Senior Member
 
scrappy's Avatar
 
Join Date: Dec 2014
Location: New Jersey
Posts: 550
Post Thanks / Like
Thanks (Given): 6
Thanks (Received): 41
Likes (Given): 42
Likes (Received): 98
Quote:
Originally Posted by bwright1818 View Post
I didn't mention that I also have an open gap checker...one that looks like a spark plug with the ground electrode removed and an alligator clip, to hook it to ground. On that test, the spark is reliable and blue. I actually took the points right out and carefully refaced them. I do this all the time on my own stuff and have great success with it. I then reinstalled them and reset them. This caused zero change in behavior of the engine. I admit that it SOUNDS as if the ignition is clearly dropping out sometimes. But again, the neon remains steady AND BRIGHT. The funny thing about single cylinder engines is that it's all or nothing. There is no comparing compression readings or doing a balance test! They can be tougher than muliti-cylinder engines because no matter what the problem is, it's either firing or not! That's one reason I will sometimes resort to the neon checkers; but I agree, that is only after an open gap test.

The funny thing with this neon test is that, usually, if the plug is fouling, the KV will go down and you can kind of see and interpret that, in the intensity of the flash. THIS flash remains bright, whether, skipping or not. Normally, that would mean lean misfire...but the plug comes out black and sometimes quite wet. I do have a squirt can with gas in it. I guess I should try that, even though I was thinking too rich.

This old blower is probably not worth the powder to blow it to ****....but now I HAVE to know the answer!
OK We are on the same page. A dead mis-fire is a no start. LOL
post up what you find.

~scrappy
scrappy is online now  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Snowblower Forum : Snow Blower Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome