300/440/550 Js440 impeller not center in jet unit. Looks like it's been hitting top of housing

80degrees

80degrees

Location
Australia
I bought a js440 and I keep finding things wrong with it.
The latest is the impeller is close and just hitting the top of the jet unit. The bottom of the jet unit and the impeller has about a 3 mill gap. I spun the motor and the gap didn't shift so it's not a bent shaft. What could cause this to happen?

Thank you
 
dbattersby20

dbattersby20

Location
New Jersey
im assuming the pumps are a similar design to the 650 pumps. cause the lining in the pumps can get warped, especially if you're using it in salt water. and then the impeller will rub. There's a list of things you can do. if it's very minor and your just want to get back out on the water quick you can try to sand/grind down the bump in the liner, best option is probably to replace the pump with a good quality used pump from the forsale section. there are also some shops that can replace the liner and it's like you get a new pump, but it ends up being way more expensive.
 
80degrees

80degrees

Location
Australia
Oh yeah I'll look around for one.
I don't think it has a bump it almost looks like the housing is sitting to low and need to be lifted up some how? I havnt pulled it appart yet so I'm not sure how it works
 
j2the-e

j2the-e

Location
AZ
You're not going to like this. First get a repair manual. You need to start over. In the 440, everything needs to be shimmed and aligned properly. First remove engine, pump and driveshaft. You install the driveshaft first, measuring and shimming it to make sure its centered. The book shows you how. Then pump goes in with shims where necessary, then engine with shims where necessary. Do it once and do it right. This is critical on the 440
 
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screaming440

screaming440

The Old Skool Professor
Location
KC/Lake of The Ozarks
80degrees said:
Any one know if they can be aligned?
Click to expand...

the 440 is not like the 550 650 ect. that have a prop shaft that the prop treads on to and splines into the drive shaft. the 440 has the prop in mounted on the drive shaft with a bushing in the pump to support the end of the drive shaft.

so it is important that you get the pump shimed or it will wear out the pump. so you got to put shims on the pump ears to get an even prop clearance.
 
80degrees

80degrees

Location
Australia
Okay so I had the pump off today I bought the bolts and shims from the wreckers. However... After I removed the pump I found there were no shims. I cleaned off the corrosion off the pump mounts and tryed to fit the shims.. If I put the shims in it makes it worse! I'm thinking it's had a thick paint job some time in its life and now does not need one. I managed to get it to fit with a little more clearance though I was to machine a little off the pump or the ski it's self I think it would fit perfectly.I also noticed that the pump bearing seal is shot! Where can I get a new one? Could this affect the center of the prop?
 
d_moss

d_moss

Location
Rexburg, ID
Convert it to a 550 pump and you will be much happier. Way easier to align and you can shim the prop tighter. The 440 pump is not really tapered and when the wear ring wears out and or the prop you just need buy new. Or get a 550 pump and shaft and throw it in. It wasnt designed in 73 more like 83 so its a better design. It also doesnt crack your bulk head like the 440 pump will.
 
screaming440

screaming440

The Old Skool Professor
Location
KC/Lake of The Ozarks
d_moss said:
Convert it to a 550 pump and you will be much happier. Way easier to align and you can shim the prop tighter. The 440 pump is not really tapered and when the wear ring wears out and or the prop you just need buy new. Or get a 550 pump and shaft and throw it in. It wasnt designed in 73 more like 83 so its a better design. It also doesnt crack your bulk head like the 440 pump will.
Click to expand...


the 550 pump is a mixed flow pump. the 440 is an axial flow pump and way better than a mixed flow pump. yes the 550 pump has some advantages but at the cost of performance.


i would not spend the money to change the driveline to a 550. just fix what you got
 
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