I know a couple people who "fix" their own cars, houses, ect... bubble gum and duct tape, if it don't fit bust out the drill! If it don't run it was a POS from the factory...it's the enginers fault! They won't ever change. I always say double check everything twice (that's four times for those of you who are still enjoying the freedom of kindergarden) it's probably right in front of your face!
my friend was trying to get his chevy 350 working properly, he did everything, carb spacer, ignition system (everything, even the distributor) pulled the heads, fought that thing for 2 or 3 weeks, missing work the whole time...spent the better part of a grand.
Turned out to be a miss adjusted carbureator...a little on the lean side!
Someone else is working on their boat, same engine, but it gets hot, had it appart twice and spends $300 a month to keep it in the water, sitting for 2 years unused because he's frustrated, took it half way appart 3 times, but won't open it up and actually look at all the individual components, just conjectures, I got over being frustrated a long time ago.