Anyone a Marine Mechanic?

I have a boat and lookin for some clues on how to fix a small but minor problem I have lol

I rebuilt my 14 boat with a 50 horse merc o/b that i have and now im working on an 18 foot 140 horse merc i/o what you trying to fix??

Well, I have a 71 Glastron 16' I/O with a Volvo Penta 4cyl (AQ130C) Dual carb 3.0l. And Im having overheating issues!!

Im very mechanically inclined. And When I got the boat I didnt know it overheated til I took it on the water, Lol, Found out the hard way. It got hot FAST, And it dieseled out everytime I shut it off. So I figured timing, I took it to my shop, Adjusted the timing, And adjusted the carbs. Seemed to run fine and rev fine, However still overheated, Figured Impeller was old or broken, Got a new one, Old one ended up being dried out. So it needed replaced. Replace it and had GREAT water flow.. However still overheated (Mind you testing out of water with a hose hooked to the inlet on the water pump before the impeller). The gauges were factory, So OLD. haha, and they were VDO gaues. I figured maybe the sending unit or gauge, Grabbed an Autometer temp gauge and installed it with new sending unit. A LOT more accurate, it takes a while to get hot but still gets hot. I pulled the thermostat housing and there is no thermostat. I figure without one it should just run cold...

I went on craigslist and called a "Marine mechanic" Whom had worked on this exact model engine many a time, HAHA, The previous owner told me the motor was recently rebuilt, I relayed that to this machanic, and he thought it to be possible that whoever rebuilt it messed up on the timing and put the chain a tooth off or so. I said okay feeseable. UNTIL..... I went to look at my boat today to figure out where Im moving my stereo too and where Im putting my other speakers and subs in there, and checked out if the chain is up front behind the water pump or in back where the transom bolts up.. low and behold its not on either. lol, there is no timing belt or chain haha its a push rod engine. So Im totally flabbergasted to whats wrong lol

My friends dad owns a marina, I can ask him about this tomorrow and see what he thinks.

Dude elbine that would be SuWEEET
Seriously, I feel like I explored everything, Oh and after adjusting the timing and making it right, Took it to the lake and it had a hard time firing up, Had to just start moving the dizzy around to find the sweet spot for it to start... And once I did that the friggin thing started missing at 1300rpm so I had to just cruise no wake style all over the lake. hehe wtf?!

Heres the engine, The yellow cap is where I have installed a fitting for a water hose to hook up to for out of water operation..

Im sure you have, but I have to ask. Have you looked to see if there is any water in the oil?

Biggest outboard they made I guess? its a 270 Everyone says its the best one for that era?