My Tractor Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter #1
Good news my brother picked up a plow (black painted) for 20 bucks at a local flea market but my wife killed the 1556 later in the afternoon. She was mowing and it stopped liked it ran out of gas. Tank was half full when checked. Motor turned over very smoothly like no compression. Spark at plug tested good when checked and compression did not register on the test gauge. What would be the first thing to check and is there any manuals for the HH 150 motor?
thanks
jason
 

·
Registered
Joined
·
1,639 Posts
I am a newbie and have exactly the same motor and problem, so I will follow this thread with great interest. First I am fixing the wiring because it will not spin the engine, but then I am working on no compression.

The "HH" is an old designation, newer model code is HO150, same engine. I found a complete parts list and diagram:
http://www.m-and-d.com/pdfs/Tecumseh/HH150-170001.pdf

-DougL
 

·
Registered
Joined
·
1,639 Posts
Thank you Dave. What motion would indicate it dropped an exhaust valve seat? And if so, what is the fix?

also up too early,
DougL
 

·
jbs1257
Joined
·
436 Posts
If your trying to check compression with a guage you are not going to be able to. It has a compression release. I believe engine needs to be spun backwards to get compression with a compression release. If it is a dropped valve seat you won't have compression anyway. Take off the head and pull the valves out. The seat can be repaired sometimes. I do believe there is a head on E-bay right now if you need one.
 

·
Registered
Joined
·
66 Posts
If your trying to check compression with a guage you are not going to be able to. It has a compression release. I believe engine needs to be spun backwards to get compression with a compression release. If it is a dropped valve seat you won't have compression anyway. Take off the head and pull the valves out. The seat can be repaired sometimes. I do believe there is a head on E-bay right now if you need one.
Hes right, most of the heavier duty tecumsehs are equipped with an MCR (compression release mechanism) so you wont be able to tell if you have compression unless you do what he says. The mechanism is spring driven and is located on the inside-facing part of the camshaft gear.
 

·
Registered
Joined
·
62 Posts
If you can get a leak-down tester rather than compression tester, you will be able to easily determine if the issue is valves (intake or exhaust), or piston/rings.
 

·
Registered
Joined
·
1,639 Posts
Thank you for the link and other info. This forum is incredible.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #11
finally got a chance to work on the old bolens. removed the rocker arm cover and found that one rocker was not moving up and down and can also pull out the push rod. the rod looks fine and not broken. would this be a sign of dropped valve seat?
thanks
jason
 
1 - 11 of 11 Posts
Top