Tecumseh OHH60 Kickback when trying to start

[leroy157]

I have a Tecumseh OHH60 engine I rebuilt. The engine runs but when I start it it sometimes has extreme kickback. I have double checked the timing, removed the flywheel and checked the condition of the key, I have set mag gap, and spark plug gap according to specks. I have triple checked everything. I am wondering if a weak mag could cause this problem becouse I noticed that the mag has a very faint spark, and you can only see it in low light. Any help would be appreciated.

 

[Russ2251]

What kind of equipment did engine power before you received it?

 

[leroy157]

Tecumseh Engine kickback

It came with the go kart frame I have modified into an AT Wheelchair but the engine needed some work to get it back up. When running it burns no oil and does not leak oil.

 

[Russ2251]

I asked the question because some powered equipment require a lighter flywheel than might be considered normal which would cause the kickback described.

 

[BriggsTwins]

these engines can be tricky or finicky. take off the valve cover, and check the valve lash. they may be out of spec for the engine. TDC valve lash spex say .004" maybe check the flywheel key while servicing the engine. it may have sheared or been knocked over a little bit.

 

[leroy157]

I have checked the flywheel key and that is in perfect condition no nicks or bending but I have not checked valve lash although upon rebuilding the engine I noticed it lose( I am an old Ford man and the old OHV1950s engines were better off with some valve lash.) But I will adjust that tonight and retry it in the morning. Thank you

 

[BriggsTwins]

Yeaa that sounds like the culprit! these little boogers run tight as all get out. I agree, first time I reco'd one of these, and left about 15 thousandths of lash, she ran as well as a two legged dog. Good luck and keep us informed!

 

[leroy157]

Tecumseh Update

I adjusted the valve lash to about .006 becouse the engine was cold and I figured more than that might cause problems when engine warmed up. After adjusting the valves I noticed that the decompression mechanisim was working properly when I slowley rotated the engine I could see the valve open slightley on the compression stroke as it should, and now the engine pulls much easier now. I will be mounting and testing tommorow. Thank you for the advice.

 

[BriggsTwins]

Awesome! glad to hear it!

 

[leroy157]

I mounted the engine today. turned on the switch and pulled the rope it fired and ran about 2 seconds. I pushed the prime button 3 times, set at 1/4 throttle, pulled the rope and it was running. It is starting on first pull but I must say that with out a choke it runs rough for a couple minutes, Temp here was 34 F when I started it. BriggsTwins you were 100% right. They run great once the valve clearance is set correctley. Thank you again.

 

[slideways]

The OHH tecumsehs run like crap until they are all warmed up. Typically i had to stand behind the kart working the throttle slowly until it would take throttle smoothly for about 5 minutes.

In some of the air cleaners there is a little red plastic baffle that is supposed to help in cold conditions if you slide it into a different slot.

 

[leroy157]

The air filter was missing on mine, there was nothing but the frame that bolted to the carborator. That was the main reason I rebuilt it. I know what running with out a filter will do to cylinder and rings. I built a filter bracket for it and I have thought of adding a butterfly type of choke to it that I could manualy control.

 

[Russ2251]

I adjusted the valve lash to about .006 becouse the engine was cold...

Lash should be .004" cold (ambient) for both valves closed at TDC.
.006" is just too wide.
The most important part of any rebuild is to have everything in spec.
From the manual (p.85):

 

[leroy157]

Russ2251: You are exactley right, But I thought I would run the engine untill it gets warm then adjust Valve Lash as I worrey about them warming up and being over tight causing valve problems. I have everything else set to specs, Mag, Spark Plug, and Carborator float level. It has a non adjustable carborator so float level is important. I also have a Briggs 6 Hp cast iron commercial engine I am rebuilding and I am debating on using it instead. It is much heaver but has adjustable carb and choke. I dont need high RPM as much as I need torque. I am undecided at present.