valve adjust

OHH engine valve adjustment

(in a nutshell)

To set the tappet gap:

Make sure the piston is on T.D.C. of compression stroke.
Intake valve: 0.005(cold).
Exhaust valve: 0.010 (cold)
Use flat feeler gauge.

From Ted Hathaway (bolenstractorsclub @ www.yahoo.com )
regarding hard starting, slow to turn over.

Last summer I overhauled my OH150. Prior to overhaul, it was extremely hard starting, even with new starter and battery. To get it to turn over, I had to spin the engine backwards by hand until it hit the backside of compression. Then the starter could get enough momentum to turn the engine over.

What I discovered during the overhaul was a worn compression release.

To check if your compression release is working, try the following.

Remove the valve box cover -
With both valves adjusted to specs, turn the crankshaft to the beginning of the compression stroke.
As you rotate the crank through the compression stroke, you should see the exhaust valve momentarily open (this limits the peak compression pressure during cranking only, making the engine easier to turn over).

It should shut before you reach TDC.

It doesn't open much, just a few thousands.

I don't have an exact spec on how far it should open. If your exhaust valve doesn't open at all on the compression stroke, you have found the problem.

The compression release mechanism is built onto the camshaft. In my engine, the pin that runs through the centre of the camshaft and actually contacts the lifter was worn to short.

I didn't want to spend the long bucks to replace the camshaft assembly, so I cheated a little…..

I added a small puddle of braze onto the lifter end of the pin.
I then lengthened the pin by approx. 0.010"- 0.015".
Next, smoothed over the top with an extra fine file.

After reassembly and adjustment of the valves, I get about .010" lift on the exhaust valve during compression.

My engine starts like new now. Please be advised that all dimensions are variable, subject to the amount of wear in your engine. My engine was a very worn out unit when I overhauled it (30 years of continuous, year round service- Bravo Bolens!). I hope these suggestions may be of help, Ted.

A problem with my personal machine (HH140).

Slow to turn over, hard to start.

Regardless of the battery and charge, the old girl would just not spin like it used to.

I dismantled the starter motor. Upon inspection of the starter, I found the brushes down to nothing.

I cleaned the armature up.

I then metered the continuity of the windings. The commutator showed fine, but looking closer, I found a broken wire on the armature. Soldered it up and things have been fine since. The break was not easy to spot. So be careful when doing any inspections.

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