Author Topic: Starting engine with low battery power  (Read 1007 times)

Peter Roach

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Starting engine with low battery power
« on: June 13, 2009, 01:12:21 PM »
The last post got me thinking about something that I have noodled over ever since I had a hand start Yanmar engine with the pressure relief valves on the top of each cylinder. If the batteries are low, the starter is acting funny, or some other reason the engine just does not want to start; is it possible to pull the compression relief lever to get the engine spinning and then push it back in to start the engine? This would give you some momentum to help you in the starting process.

My question is - can I damage the engine by doing this?

I tried having a bad day once but I did not like it

Warren Daniels

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Starting engine with low battery power
« Reply #1 on: June 23, 2009, 04:04:32 AM »
Peter,
Chances are very good to almost certain that the compression of the cylinders will be great enough to stop the pistons.

Steven Rice

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Starting engine with low battery power
« Reply #2 on: July 06, 2009, 09:16:27 AM »
It is possible IF you have a compression release system. I had a Volvo MD-40 (I think it was 26 hp?) in an Albin Ballad in Europe that I had to hand crank that way several times. It was actually fairly easy. I know there is no provision in the Perkins or Westerbekes, but there might be on a Yanmar. In the HP range of our engines, pure inertia and weight probably make it undesireable, even if it is possible! You have to get fairly high revs before you close the compression release lever - about as fast as I could crank when I was 45!

Peter Roach

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Starting engine with low battery power
« Reply #3 on: July 06, 2009, 10:02:48 PM »
Quote from: Steven Rice
It is possible IF you have a compression release system. I had a Volvo MD-40 (I think it was 26 hp?) in an Albin Ballad in Europe that I had to hand crank that way several times. It was actually fairly easy. I know there is no provision in the Perkins or Westerbekes, but there might be on a Yanmar. In the HP range of our engines, pure inertia and weight probably make it undesireable, even if it is possible! You have to get fairly high revs before you close the compression release lever - about as fast as I could crank when I was 45!

Steve - I had a Yanmar with compression release valves on each cylinder. You would open them all up and start cranking the engine. When you got sufficent rpms you would close the first lever. This would start a very rough running engine. The compression release valves would then automatically close to get the entire engine running. It was pretty easy. It was even easier if you had ANY battery power and could use the starter without a load.
I tried having a bad day once but I did not like it