ym240 compression test

[jbrd]

First, Thanks for all the great information from you guys. What is the recommended way to do a compression test? Leave one injector in, or take both of them out. Thanks, jbrd

 

[clemsonfor]

in a boat motor i know your supposed to pull all the plugs. Tractor diesel? I would assume that would hold true but i have no idea? I think the reason for pulling spark plugs is to let the motor spinn up faster than wth compression an all cylinders.

 

[winston1]

Yes, according to a service manual for a ym220/226 you should take them all out and have a hot battery. Compression readings are to be taken at 300rpm. I'm assuming that is starter rpm. I know yours is a 2 cylinder and a different beast but I think same rules would apply.