Re: Just bought a boat and having bad issues
WELL........................
It just don't work to buy a misfunctioning bote, yell to a bunch of friendly good guys for help, and expect a cheep silver bullet to get you in the tournament in a day.
You start with a compression check, and maybe peek in the bores, a borescope helps, and see if the motor is in general good health, or if it has major mechanical problems.
Then you check out the fuel system. You put some pressure on it with the primer bulb, (a hard squeeze is about 6-7 lbs pressure) and check for leaks, carbs flooding, stuff like that. Replace the fuel filter, all old hard fuel lines, and throw a kit into the fuel pump.
If the plugs are old, dirty, or gummed up, replace them.
Then you do a formal link n sync on it to be sure all the timing is right, both spark and throttle advance.
If it'll run pretty good on the cuffs about now, it's time to do a decarbon job on it.
Then you can start to troubleshoot faults. Until this point, you are working with a completely unknown engine, and you have no way to decide if something is significant, and what the fault might be. If it's the victim of long term lazy maintenance, you may have already fixed it by now.
I believe you have either a 2.4 or a 2.5 carb'd V6. These are some of the strongest, most reliable motors Mercury made. The race boys like to push them to over 9000 rpm and 300 + ponies on their skipstones. They don't last long at that, but at 5500 rpm, they are just loafing.
The lower unit is another story. On an engine this size, a water leak that is an inconvenience on a 25 horse engine will put the pinion out the side in a heartbeat on this one. Preventative maintenance, proper adjustment, and good lube are required. They can live forever on a fishin' motor if well cared for, and they can trash in an hour if not.
Good Luck
John