I would never use lag bolts where water splashes up and wicks into crevices.
Why not S S nuts, bolts and washers where needed ? I use Silicone sealant. Silicone is very gentile, when pulled apart with a hair dryer, to loosen it up. Done it.
How many tanks of gas have run thru the sparkplugs in the engine ? Pull them out See if they are coated a lot with black oil. You might just need new sparkplugs. Check and reset gaps BEFORE installing.
Maybe Depends on what the alarm module is feeling for water. Some, most, engines do not sound OVERHEAT at even 212 F. Steam can be coming out in cars. No alarm to warn you. They save pennies by telling you to watch the dash meter.
What evidence do you have that you need to tear apart the carbs ? If you just feel like doing it ? Take it apart and have real problems after you reassemble it. You can make a simple problem into a endless series of .....What Ifs.
Been there and screwed up perfectly good engines.
Both of my...
Excessively HOT engine. Crummy gasoline.
I would get a infrared dot thermometer. And check temperature as soon as you stop the boat. But before turning off the engine.
Next time. Before stopping the engine. In NEUTRAL hold the engine speed at a fast idle. To allow cool circulating water to...
Airshot
I had a driveway excavator reuse the stones in my 225' X 10' driveway. He then laid out a Recycled Asphalt mixture of small stones in the Asphalt. Packed it down 2 years ago. Has survived cars and smaller delivery trucks very well. $ 3,400.
ALL idle MIXTURE adjustment screws. Are adjusted by listening to the SMOOTHNESS of the engine warmed up in forward gear. While the boat is moving in water.
You are surprised by a 1986 engine having a problem ? Have a good mechanic check out the engine.
Before you do more damage to it.
Get the water out of all the cylinders. The Piston rings may be rusting now.