Re: 1978 105 chrysler
The '78 Chrysler 105 does not have the failure prone Magna Power II ignition, so you should be ok on that point. The basic block is the lowest horsepower offerred in the 4 cylinder block so it is less stressed than higher HP models. If not abused, it will be relatively trouble free. If it is running, it will be a relatively inexpensive entry into boating.
The basic test you need to do is to remove all the spark plugs and turn over the flywheel by hand. It should turn freely and easily and you should be able to feel slight crancase compression, indicating the reeds are good and the crankcase seals are ok. Hopefully it hasn't been sitting too long and will show signs of retained oil. You might even hear the reeds "honk" a little. Then, while turning the flywheel by hand put your thumb over each plug hole. Each cylinder will either have compression or not. If any one does not have compression, the piston is damaged--walk away--the engine needs rebuilding.
However, if it does need repair and you get it for next to nothing, a complete rebuild, if you do the work yourself, will cost around 800 in parts. And most parts are available. You may not be able to get them locally, but you will certainly be able to get them on line. The engine is almost dirt simple and very easy to repair. People tend to scorn them and they have a bad reputation because they never put out the same horsepower as a Merc or Rude, but they really are no better or worse that most engines. As inexpensive basic transportation, they can't be beat. I own somewhere between 15-18 Chryslers and Forces of all sizes. My primary engine is a '79-'80 Chrysler 140 pushing a 21 foot cuddy.
