How long does it take for water pump to cycle water up to thermostat hose?

[Augoose]

Hey all,
I've got a '89 4.3 merc with the Alpha 1, gen 1 lower. I'm summerizing and just put the lower unit back on today, along with some other maintenance.

My question is how long does it take for water to pump up to the thermostat hose in the engine? I connected new earmuffs, good seal, and ran the water at full pressure for about 2 mins before starting the engine. I allowed the engine to run no more than 10-15 seconds before cutting it off as the thermostat hose still had no pressure to it.

It has a new impeller with key installed an as part of summerizing, I poked a wire in all the system drain holes along with running a wet dry vac to suck out any debris, so I'm reasonably confident there isn't an obstruction.

Did I not give it long enough to cycle the water through?
thanks

 

[Don S]

Re: How long does it take for water pump to cycle water up to thermostat hose?

15 seconds is plenty of time to get water to the thermostat housing. If you don't have water to the housing, you have a problem.
Did you install new gaskets when installing the impeller?

 

[Augoose]

Re: How long does it take for water pump to cycle water up to thermostat hose?

Brand new. Also lubed up the impeller itself according to directions

 

[Augoose]

Re: How long does it take for water pump to cycle water up to thermostat hose?

Alright, false alarm. I removed the hose to the thermostat - it was indeed full of water. I suppose that since the engine was only running for a few seconds, no heat had yet built up and therefore, no pressure in the hose.
Sorry about that - just paranoid with the first startup this year.
Thanks Don

 

[Don S]

Re: How long does it take for water pump to cycle water up to thermostat hose?

You are never going to build up noticable pressure from the raw water pump while on muffs. It may also take longer than 15 seconds to fill the cooling system on a raw water cooled engine that has been drained for winterization.

 

[Augoose]

Re: How long does it take for water pump to cycle water up to thermostat hose?

thanks Don, I was just overly cautious and figured I'd ask a question before damaging something.

 

[Don S]

Re: How long does it take for water pump to cycle water up to thermostat hose?

thanks Don, I was just overly cautious and figured I'd ask a question before damaging something.

That's the best way to do it. Good luck with your boat.