How can I check cranking RPMs?

[phillipboggs]

I have a 1987 Evinrude 48 SPL that I need to check the cranking RPMs on. Can anyone tell me how to do this? Thanks in advance.

 

[ondarvr]

Re: How can I check cranking RPMs?

You can either use a tach, or learn to count very fast.

 

[Tim Frank]

Re: How can I check cranking RPMs?

A contact tachometer is what you want.
http://www.multimeterwarehouse.com/tahcometer.htm

 

[phillipboggs]

Re: How can I check cranking RPMs?

Thanks Ondarvr, but I only have 10 fingers and 10 toes, so that won't work for me....

 

[Lion hunter]

Re: How can I check cranking RPMs?

I'm curious as to why.

 

[F_R]

Re: How can I check cranking RPMs?

I would assume the "why" is because he read that it has to be cranking a minimum RPM in order to get an ignition spark.

Actually, if that is the reason, all he has to do is try it with the spark plugs removed. If it has spark with the plugs out, but not with them in, it is a cranking speed problem.

EDIT: ---OR a weak ignition problem such as bad charge coils.