BF45 overheating help needed

Hi all,
i have a BF45 honda she has been sitting for a couple years and i wanted to get her running to go out fishing, she always ran with no problems, so i charged up a battery i had and fired her up when i did i used water cups and hose for cooling but nothing was coming out pee tube. i ran it for a little bit but didnt want it to overheat after running for a bit i could tell it was getting hot and shut it down. i figured i needed to replace impeller anyway so i dropped lower end and sure enough it was shredded and looked a little burnt and melted. i cleaned everything out and ran water down from thermostat and water ran down tube into lower unit i had to unplug pee tube to get it to flow out that side but it does. i installed new Impeller/pump kit (was not honda OEM because was in a hurry to get before weekend) i fired her back up and same thing no water through pee tube so i loosened the thermostat housing with no thermostat in it and just air is blowing out. i have engine lowered into tub now just to make sure it has water. what could it be?

sorry for such a long post i just wanted you to get all the info

Note there is a water intake in the lower unit right above the prop that's difficult to see. If the water supply going to the cuffs is weak, this intake will suck air, allowing the pump to overheat.

If running the motor on cuffs, you need a water supply that will have no trouble supplying a LOT of volume with good pressure - like you might have on a city water supply. And even then you don't want to rev the engine much over an idle.

Pretty sure they sell a LOT of water pumps for this engine (all Honda 35-50hp) because of this extra water intake.

The better plan is to back the motor into a lake to a depth that allows for a couple inches of depth above the pump -OR- cur down a trash can to fit and use that - with the same caution the water level MUST be above where the pump is located in the lower unit.

Regarding to pee tube (pisser), sometimes a piece of weed trimmer line can be used to clear it. On occasion, I've had to pull the fitting from the block, leaving a much bigger hole for the water and any crap to escape. Once that is clear, water will be shooting everywhere, so you'll need to keep an eye on it and be prepared to shut it down quickly.

Well, basically....what Alan said.

But you say you have tried it in a tub? If so, good move.

But do you have the water level in the tub high enough? I like to see the water at least 1" above the anti-cav plate but higher is even better.

Sorry to say that you may have doofed your new pump already by starving it. It only takes a few seconds running without water and prime to kill a pump.

I would be going back and at least looking at it. And, while in there, inspect CLOSELY the drive key for being out of place or cocked over and for wear if you didn't replace it before.

Also, make sure that no critters got in to the water intake and built some sort of scary nest during the long layup. Hopefully you did account for as much of the old impeller as you could before...right?

Good luck.

thanks for the replies
i made sure everything was cleaned out of all screens and water in tub is above fins and above pump, what i dont get is where is all the air coming from? if the lower end is totally in water you would think if submerged water would have to at least spit out but nothing but air...i have taken back apart 4 times and put back together with same result.....i guess i take it to the lake and make sure there is plenty of water but i am sure that the tub is deep enough.