Impeller overheating

[Gantz6]

I have a 2001 bf50a which had a weak tell tale so i decided to replace impeller. With one intake blocked with tape, as i always do when using muffs, i started motor after reassembly and zero water from telltale and smoke from lower unit by shifter after 10 seconds or so, i shut down took it apart and impeller melted! I ordered another but in meantime I reinstalled old one and tried again, no water and light smoke i shut it down quickly. This time old impeller looked ok, not melted like the first. What now should i flush from thermostat to be sure nothing is blocking?

 

[ThomW]

Definitely make sure no rubber pieces are caught up in the water tube if the other impeller got smoked. Did you ensure the key that holds impeller in place was installed back on the shaft? If the impeller was destroyed, it would seem like it wasn't getting water...
Most muffs pump water through only one side. Was the tape on the opposite side or the side you taped?

 

[MattFL]

There are 3 water intake vents; one on each side of the lower unit, PLUS one on the bottom of the anti ventilation plate just above the prop. You've got use ears that flow enough water that you have water pouring from that vent over the prop. Alternatively you can block that vent with tape, but it's not necessary if you have good ears. Also when you re-assemble the water pump, use grease in the cup and on the wear plate. Now that you've melted things, look carefully under the wear plate to see if any of the plastic also melted. Replace anything melted.

 

[Gantz6]

Definitely make sure no rubber pieces are caught up in the water tube if the other impeller got smoked. Did you ensure the key that holds impeller in place was installed back on the shaft? If the impeller was destroyed, it would seem like it wasn't getting water...
Most muffs pump water through only one side. Was the tape on the opposite side or the side you

There are 3 water intake vents; one on each side of the lower unit, PLUS one on the bottom of the anti ventilation plate just above the prop. You've got use ears that flow enough water that you have water pouring from that vent over the prop. Alternatively you can block that vent with tape, but it's not necessary if you have good ears. Also when you re-assemble the water pump, use grease in the cup and on the wear plate. Now that you've melted things, look carefully under the wear plate to see if any of the plastic also melted. Replace anything melted.

I always tape bottom of plate when flushing and its been fine. I just dont understand how the impeller overheated with water running. Now i feel i need to reverse flush thru thermostat and teltale before installing new one

 

[Gantz6]

Definitely make sure no rubber pieces are caught up in the water tube if the other impeller got smoked. Did you ensure the key that holds impeller in place was installed back on the shaft? If the impeller was destroyed, it would seem like it wasn't getting water...
Most muffs pump water through only one side. Was the tape on the opposite side or the side you taped?

It does seem like it wasn’t getting water which is where im lost. I flush motor the same way on muffs all the time the taped is over intake above prop on my motor thats fine.

 

[Gantz6]

It does seem like it wasn’t getting water which is where im lost. I flush motor the same way on muffs all the time the taped is over intake above prop on my motor thats fine.

Key was in also

I have a 2001 bf50a which had a weak tell tale so i decided to replace impeller. With one intake blocked with tape, as i always do when using muffs, i started motor after reassembly and zero water from telltale and smoke from lower unit by shifter after 10 seconds or so, i shut down took it apart and impeller melted! I ordered another but in meantime I reinstalled old one and tried again, no water and light smoke i shut it down quickly. This time old impeller looked ok, not melted like the first. What now should i flush from thermostat to be sure nothing is blocking?

i removed thermostat and flushed from top thank God because pieces of hardened rubber came out and also blew clear telltale line which also seemed restricted. I guess ill just wait to install impeller and hopefully thats it! Not sure why it melted to begin with tho but lower unit is also running clear with hose

 

[ahicks]

While you have it apart, look UNDER the water pump to make sure there are no restrictions on the intake side of the pump - like more impeller pieces.

 

[Gantz6]

After removing thermostat and flushing motor from top and telltale hose, I reinstalled everything including old impeller which was ok for testing, ran motor on muffs and pump is not moving water! Could base be warped or bolts not tight enough to seal housing? Dont want to overtighten and crack something but thats the only thing i can think of. The old impeller overheated like the other one and zero water from peehole which is clear.

While you have it apart, look UNDER the water pump to make sure there are no restrictions on the intake side of the pump - like more impeller pieces.

when i took pump apart originally i noticed one gasket, which is supposed to be under the base was on top of it over O ring under plate, also after looking closely the impeller cup was installed with locking notch in wrong place. I bought motor used last year and it ran great but i never liked the strength of the exit stream now maybe i know why. Also the housing base seems slightly uneven near shaft maybe thats reason for extra gasket? Could that cause suctioning problem with impeller? The outer rim seems to be fine. I ordered new pump base anyway and a little worried to try another impeller but thought if i ran it in bucket instead of on muffs it might at least pump water. Seems to me the base of pump has to be the issue

 

[Gantz6]

After removing thermostat and flushing motor from top and telltale hose, I reinstalled everything including old impeller which was ok for testing, ran motor on muffs and pump is not moving water! Could base be warped or bolts not tight enough to seal housing? Dont want to overtighten and crack something but thats the only thing i can think of. The old impeller overheated like the other one and zero water from peehole which is clear.

when i took pump apart originally i noticed one gasket, which is supposed to be under the base was on top of it over O ring under plate, also after looking closely the impeller cup was installed with locking notch in wrong place. I bought motor used last year and it ran great but i never liked the strength of the exit stream now maybe i know why. Also the housing base seems slightly uneven near shaft maybe thats reason for extra gasket? Could that cause suctioning problem with impeller? The outer rim seems to be fine. I ordered new pump base anyway and a little worried to try another impeller but thought if i ran it in bucket instead of on muffs it might at least pump water. Seems to me the base of pump has to be the issue

 

[Gantz6]

Does that look like enough to cause a problem?

 

[ahicks]

If you're asking would I reuse it, the answer would be no. While you have that off, did you look to make sure there was nothing between it and the intake screens?

I've seen that pump get hot enough to melt the upper plastic piece, to the point where the stainless cup is riding hard on the drive shaft, to the point it will wear a groove in it.

 

[Gantz6]

If you're asking would I reuse it, the answer would be no. While you have that off, did you look to make sure there was nothing between it and the intake screens?

I've seen that pump get hot enough to melt the upper plastic piece, to the point where the stainless cup is riding hard on the drive shaft, to the point it will wear a groove in it.

I took the screens off and everything is clear up to pump. I saw video of a guy who tested pump with a drill on the drive shaft seems like a good idea before putting lower unit back on. Could tell right away if pump is working how does that sound?

 

[ahicks]

Sure!

 

[Gantz6]

Sure!

Should be Such a simple project!!

 

[Gantz6]

Well i reassembled with another impeller and greased Orings and seals and put new gaskets in the proper places and its works better then it ever did. Im sure it had blockages so overall being forced to flush everything from thermostat down and seeing what came out and the difference it made made all the frustration worthwhile. I really appreciate the help thanks!

 

[ahicks]

Love these happy endings!

Thanks for getting back with us on your results! -Al

 

[ThomW]

Glad you're up and running again!