Mercruiser startup

[jere1972]

Hey guys need some advice, picked up a used mercruiser setup, 7.4L bravo, engine has been dormant for over 5 years, I am a little reluctant on trying to start it without doing something, almost all the internal components have not seen oil in over 5 years, this is where my concern lies, I have replaced things like starter circ pump raw water kit, hoses, belts drained the oil (very black), put in fresh oil, new filter, swapped out the carb from my 7.4 yamaha engine (same carb but clean) should I do anything or spray any thing into the cylinders, thought about removing the distributer to spin the oilpump, i have not turned the engine over yet with the exception of turning it a few degrees with a breaker bar to make certain it was not froze

 

[AviatorJim]

Re: Mercruiser startup

My recommendation may result in your engine suffering a lot of wear due to rust in the cylinders!!! But I almost make a hobby of starting up engines that have spent a decade rusting.

But that being said, if you have rust in the cylinders, you already have a lot of wear, and not much to lose. You probably have stuck lifters, and maybe stuck valves. I like to hit the valve stems with a plastic mallet to make sure they move. A good shot of fogging oil in each cylinder, or a good shot of engine oil too, then remove the spark plugs and crank it over a few times until oil pressure is indicated should do it.

Cranking it over with the cylinders not firing won't put any real load on the bearings. It will scrape stuff off the cylinder walls, then blow it out the sparkplug hole. If you have real nerves of steel, you can crank it over using 2 12V batteries in series (24V). Lots more torque to the starter, and great airflow. Don't over do it, but cranking 10 sec at a time won't hurt. Be sure that you are only connected to the starter, and EVERYTHING else is disconnected from the starter, or you will burn up all your instruments and radios. Then put in the plugs and fire it up.

--Jim

Good luck

 

[tpenfield]

Re: Mercruiser startup

Over the winter . . . I usually remove the spark plugs and spray some fogging oil into the cylinders. Then with the plugs still out, I spin the engine with the starter and wait until I get some oil pressure reading on the gauge.

Soooo, you might want to try something like that with a 5 year layup . Then check to see if you got rust out of the cylinders, etc.

If all looks good, put the plugs in and see if it will fire up for real.

 

[Bondo]

Re: Mercruiser startup

Over the winter . . . I usually remove the spark plugs and spray some fogging oil into the cylinders. Then with the plugs still out, I spin the engine with the starter and wait until I get some oil pressure reading on the gauge.

Soooo, you might want to try something like that with a 5 year layup . Then check to see if you got rust out of the cylinders, etc.

If all looks good, put the plugs in and see if it will fire up for real.

Ayuh,.... Exactly,... Pull the spark plugs 'n crank it on the starter to build oil pressuse, 'n prime the fuel pump/ carb...