Engine advice needed!Volvo MD3//Yanmar 3QM30

[geoleo]

I have a older 1971 wood ketch with a original Volvo MD3. It doesen run -seems the fuel injector pump is faulty--1 cyl squirts feebly-another barely and the third not at all from the ports where the injector tubes are connected to the pump.With the boat comes a "spare engine for parts -however this engine is in Tennessee and Im in Tampa.Im thinking of going there and stripping the heads,and of course the injector punp--however this is still a old engine and may do lotsa work and still not work!(old story I know)Im concerned that I wont get the timing right when I switch injector pumps(flying blind here).Today a new possibility sprang up- I can get a Yanmar 3QM 30----for $1500 however it has a transmission problema in that at slow speeds it jumps out of forward gear! Does anyone here know what the cause and fix is for this?I had a yanmar engine like this before and it worked perfectly for 12 years and I had bought it used too...............HELP!