Advice Requested About Restart

[DennisM]

My boat is scheduled for relaunch next week. Over the winter, the maintenance I performed on the engine (Yanmar 3GM30F) drained out quite a bit of the antifreeze that would normally be in the hoses and other areas of the cooling system. I gooped up the impeller with Vaseline, in the hope that it will run dry for awhile without disintegrating, but my questions are these:

Should I simply try and restart the engine after launch despite the additional amount of air in the cooling system? If not, is there some way I should add water or antifreeze? If it's okay to try to start the engine as is, is there an amount of time I should not crank it past? Should I try to advance the flywheel manually to fill the cooling system?

All advice welcome. Thank you in advance.

[Sailmonkey]

If your impeller isn't nitrile rubber or other similar oil resistant material you'll want to take it back out and replace it without the Vaseline.

Other than that, fill it up with coolant, start and run for a minute, shut off and check the coolant level. Of there is a water heater on the circuit, is it higher or lower than the engine?

[DennisM]

Originally Posted by Sailmonkey

If your impeller isn't nitrile rubber or other similar oil resistant material you'll want to take it back out and replace it without the Vaseline.

Other than that, fill it up with coolant, start and run for a minute, shut off and check the coolant level. Of there is a water heater on the circuit, is it higher or lower than the engine?

Thanks, Sailmonkey! The impeller appears to be EPDM (artificial rubber). I'm pretty sure it's oil-resistant. The water heater is higher than the engine. What should I know about that?

Upon re-examining my initial questions, I realize I may not have been clear. The system with additional air is only the raw water system: intake to raw water strainer (which is full of antifreeze), strainer to pump, hose from pump to heat exchanger, probably the heat exchanger itself.

[Sailmonkey]

Don't worry about the raw water system. Impeller pumps are self priming (within reason) and will just do their thing.
I only asked about the water heater as they're a pain to purge air out of the heat exchange loop when they're above the engine.

[DennisM]

Originally Posted by Sailmonkey

Don't worry about the raw water system. Impeller pumps are self priming (within reason) and will just do their thing.
I only asked about the water heater as they're a pain to purge air out of the heat exchange loop when they're above the engine.

Thanks again! Your advice is very helpful. I'll crank it, and see what happens.