We did some assessment on the 1971 SeaCamper’s MerCruiser 165 engine yesterday. This is a Chevy inline 6 built in 1970. Our first mystery to solve was the hour meter on the dash, which reads 4502. I had two AI’s debating each other on whether the last digit is tenths. Grok said it was, and that the meter truly reads 450.2. Claude was adamant that it reads 4,502, reasoning that the sweep hand on the dial negates having a tenths reel. Grok countered that at 4,502 hours the engine would either be scrap or have already undergone at least one, maybe two overhauls. There was only one way to find out for sure so I put 12V directly to the back of the meter to confirm the movement of that last digit.
Turns out Grok was right, the last digit is tenths, and the meter does truly only register 450.2 hours. But while R&R’ing the meter I discovered that the ground wire to it was broken, therefore rendering its reading a moot point. Who knows how long the engine ran without turning those dials? So it was time to look inside the engine itself and see what we could see.
It was New Tool Day so I pulled the plugs and used my new borescope to look around inside the cylinders. The good news is that they all looked about the same, with no obvious signs of breaks, cracks, gouges, etc. The bad news is, and please note that I’m not an expert in this, but it looks like a well-used engine in there. Moderate carbon buildup, some signs of vertical scoring, and even what looks to be some faint rust pitting though nothing actually looks “rusty” in there. The oil looks clean, like it was last changed before the boat got put away for the season over 25 years ago. So my best guess as a layman is that this just looks like a well used, high hours but probably regularly maintained engine. But it’s not in a condition that I would just try to get it running and leave it in there.
The engine has to come out, even if we keep it, for a proper overhaul. Which then begs the question, will it ever go back in? It will still be the low-cost option, to freshen this one up along with its outdrive and stick it back in there. Option 2 is the Volvo-Penta/Ford 5.8SFI V8 that’s currently sitting on my shop floor. It would also need to be gone through, I have the transom mount and gimbal for the outdrive but would still need to source the rest of the outdrive. Or do we go with Option 3, buy or build an outboard conversion bracket and try to find a good used 200 to 250 HP 4-stroke outboard? That would probably be the highest cost option but it would gain us a huge trunk space in the vacated engine bay.