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BF50A Backflush

B

brunsonc

New member
"Just got done replacing old w

"Just got done replacing old waterpump and cleaning the carbs and the motor is running awesome. But, I'm pretty sure that some of the old impeller is still in the cooling system because every now and again the pee stream gets really weak. My question is, how exactly do you do a backflush to get this stuff out? Do I need to remove the lower unit and where do I back flush from. Thanks, any tips are appreciated."
 
"I would recommend pulling the

"I would recommend pulling the lower unit off and checking first under the water pump for any impeller parts that may have fallen in there between the intake and the water pump if you have not already checked there. That is normally where many pieces go. The pieces could be just partially blocking the intake at the water pump. Remove the intake grates and backflush from the water pump down.

While the lower unit is off, pull the thermostat (rear port top of the engine...you have to remove the timing belt cover to get to it) backflush with a garden hose from the thermostat. Check how the water is coming out the pickup tube and how it is coming out the telltail indicator. If the telltail is questionable, remove the telltail hose from the connector that goes through the cowling. It may be just a little piece in the telltail hose at the fitting. Hopefully, it is small enough to come out the hose or it is stuck in the cowling fitting. Make sure the fitting is clear (a paper clip works good)

Also check for debris in the thermostat while you are at it."
 
"Also a problem I had was I ha

"Also a problem I had was I had not done up the bolts tight enough when i replaced my impeller. Not being done up tight enough let air in so sort of caused an airloc esp as I was moving along at pace (water pump was prett much out of the water. After I sat at idle for a few minutes and tried to clear what I thought was a blocked tell tail it would piss out again.

Just a thought, cause I pulled all mine apart only to find nothing worked till I snugged the bolts down"
 
"I backflushed from the thermo

"I backflushed from the thermostat last night and only got one pea sized piece of debris to flush out. The water was flowing fine thru the pickup tube, but was weak out of the telltail. I checked the hose and the connector at the cowling and they were both clear.....I'm guessing my next step is to remove the nipple from the motor that the pee hose connects to and try to flush whatever is in there out...what do you guys think???"
 
"Try your backflush again and

"Try your backflush again and put your finger over the pickup tube to block its flow out there...that will create more pressure to the telltale area. More than likely, the flow will improve out the telltale.

If you have a source of compressed air...blowing it back through the telltale hose may help dislodge whatever may be in there if the flow does not improve when you plug the pickup with your finger."
 
"I have a BF50A that has been

"I have a BF50A that has been a great motor aside from the fact that the telltale is always getting plugged.
Recently had the lower unit removed and water pump serviced with new impeller thinking that would solve the problem.
No such luck.
I usually disconnect the water tube from the plastic fitting and poke a wire into the tube through the nipple into the engine.
Most often i can clear it, but sometimes it's a job.
I think the water passages are small enough that any small particles sucked up will lodge and restrict flow.
I know others that have had the same problem."
 
wonder if i could just drill o

wonder if i could just drill out the fitting that's on mine now? that could solve a lot of problems.
 
Anybody????........

I can't believe no one has drilled thier fitting out to match the newer one. I can't think of anything bad that could come from it.

Thoughts?

B
 
Seems to me like that would work too...
why bother replacing with a new fitting if it could be drilled out to create
a larger diameter flow through the existing one ?
 
I removed the fitting and sure enough it was plugged with bits of junk
cleaned it out and she pee'd like a race horse.
later on it plugged again , had to repeat the procedure.
the oriface is small enough that any debris will likely plug it.
 
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i'll check this afternoon. i don't remember off the top of my head.

i already had the nipple to the cowling removed, i had "straight piped" it a while back to cut down on that restriction. i also have my hose turned up so it pees straight back almost. i don't have to look back to check that it's peeing, just listen to the stream hitting the water (quiet 4 strokes are great).
 
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